WorldWideScience

Sample records for registry-based twin study

  1. Heredity In Sarcoidosis - A Registry-Based Twin Study

    DEFF Research Database (Denmark)

    Sverrild, Asger; Backer, Vibeke; Kyvik, Kirsten Ohm

    2008-01-01

    BACKGROUND: Sarcoidosis is a multiorgan, granulomatous, inflammatory disease with unknown aetiology. Familial clustering of cases and ethnic variation in the epidemiology suggests a genetic influence on the disease susceptibility. AIM: This paper reports twin concordance and heritability estimates...... of sarcoidosis in order to assess the overall contribution of genetic factors to the disease susceptibility. METHODS: Monozygotic and dizygotic twins enrolled in either the Danish or the Finnish population-based, national Twin Cohorts (61,662 pairs in total) were linked to diagnostic information on sarcoidosis.......012. Compared to the general population we found an 80-fold increased risk of developing sarcoidosis in co-twins of affected monozygotic brothers or sisters. The increased risk in dizygotic twins was on the other hand only 7-fold. Aetiological model fitting gave a heritability of sarcoidosis of 0.66 (95% CI 0...

  2. Academic performance in adolescents born after ART-a nationwide registry-based cohort study.

    Science.gov (United States)

    Spangmose, A L; Malchau, S S; Schmidt, L; Vassard, D; Rasmussen, S; Loft, A; Forman, J; Pinborg, A

    2017-02-01

    Is academic performance in adolescents aged 15-16 years and conceived after ART, measured as test scores in ninth grade, comparable to that for spontaneously conceived (SC) adolescents? ART singletons had a significantly lower mean test score in the adjusted analysis when compared with SC singletons, yet the differences were small and probably not of clinical relevance. Previous studies have shown similar intelligence quotient (IQ) levels in ART and SC children, but only a few have been on adolescents. Academic performance measured with standardized national tests has not previously been explored in a complete national cohort of adolescents conceived after ART. A Danish national registry-based cohort including all 4766 ART adolescents (n = 2836 singletons and n = 1930 twins) born in 1995-1998 were compared with two SC control cohorts: a randomly selected singleton population (n = 5660) and all twins (n = 7064) born from 1995 to 1998 in Denmark. Nine children who died during the follow-up period were excluded from the study. Mean test scores on a 7-point-marking scale from -3 to 12 were compared, and adjustments were made for relevant reproductive and socio-demographic covariates including occupational and educational level of the parents. The crude mean test score was higher in both ART singletons and ART twins compared with SC adolescents. The crude mean differences were +0.41 (95% CI 0.30-0.53) and +0.45 (95% CI 0.28-0.62) between ART and SC singletons and between ART and SC twins, respectively. However, the adjusted mean overall test score was significantly lower for ART singletons compared with SC singletons (adjusted mean difference -0.15 (95% CI -0.29-(-0.02))). For comparison, the adjusted mean difference was +2.05 (95% CI 1.82-2.28) between the highest and the lowest parental educational level, suggesting that the effect of ART is weak compared with the conventional predictors. The adjusted analyses showed significantly lower mean test scores in mathematics

  3. Nordic registry-based cohort studies: Possibilities and pitfalls when combining Nordic registry data.

    Science.gov (United States)

    Maret-Ouda, John; Tao, Wenjing; Wahlin, Karl; Lagergren, Jesper

    2017-07-01

    All five Nordic countries (Denmark, Finland, Iceland, Norway and Sweden) have nationwide registries with similar data structure and validity, as well as personal identity numbers enabling linkage between registries. These resources provide opportunities for medical research that is based on large registry-based cohort studies with long and complete follow-up. This review describes practical aspects, opportunities and challenges encountered when setting up all-Nordic registry-based cohort studies. Relevant articles describing registries often used for medical research in the Nordic countries were retrieved. Further, our experiences of conducting this type of study, including planning, acquiring permissions, data retrieval and data cleaning and handling, and the possibilities and challenges we have encountered are described. Combining data from the Nordic countries makes it possible to create large and powerful cohorts. The main challenges include obtaining all permissions within each country, usually in the local language, and retrieving the data. These challenges emphasise the importance of having experienced collaborators within each country. Following the acquisition of data, data management requires the understanding of the differences between the variables to be used in the various countries. A concern is the long time required between initiation and completion. Nationwide Nordic registries can be combined into cohorts with high validity and statistical power, but the considerable expertise, workload and time required to complete such cohorts should not be underestimated.

  4. Radiotherapy for bone metastases - Practice in Norway 1997 - 2007. A national registry-based study

    Energy Technology Data Exchange (ETDEWEB)

    Sande Laugsand, Tonje [European Palliative Care Research Centre (PRC), Faculty of Medicine, Norwegian Univ. of Technology and Science (NTNU), Trondheim (Norway)], e-mail: tonje.laugsand@ntnu.no; Kaasa, Stein; Lund, Jo-Aasmund [European Palliative Care Research Centre (PRC), Faculty of Medicine, Norwegian Univ. of Technology and Science (NTNU), Trondheim (Norway); Cancer Clinic, St. Olavs Hospital, Univ. Hospital of Trondheim, Trondheim (Norway); Romundstad, Paal [Dept. of Public Health, Faculty of Medicine, Norwegian Univ. of Technology and Science (NTNU), Trondheim (Norway); Johannesen, Tom Boerge [Cancer Registry of Norway, Oslo (Norway)

    2013-08-15

    Numerous randomised clinical trials have shown that the efficacy of single fraction radiotherapy for metastatic bone pain corresponds to that of multiple fractions of radiotherapy for the majority of patients. It is not clear to which extent single fraction radiotherapy has been implemented into clinical practice. Material and methods: A Norwegian national registry based study was conducted, including all radiotherapy schedules of 8 Gy x 1 and 3 Gy x 10 delivered to bone metastases in 1997 - 2007. Binomial regression analyses were used to study whether treatment centre, primary diagnosis, anatomical region irradiated, age, sex, and travel distance, were associated with the choice of fractionation. Results: A total of 14 380 radiotherapy episodes were identified. During the period 31% of the treatments were delivered as 8 Gy x 1. The proportion of single fraction treatments increased from 16% in 1997 to 41% in 2007. There were substantial differences in the proportion of single fraction treatments between the treatment centres (range 25 - 54%). These differences persisted after adjustment for sex, age, primary diagnosis, anatomical region, and travel distance. Conclusions: The study demonstrates an under utilisation of single fraction treatment for bone metastases in Norway during the study period.

  5. The effect of enteral tube feeding in cystic fibrosis: A registry based study.

    Science.gov (United States)

    Libeert, Denis; Declercq, Dimitri; Wanyama, Simeon; Thomas, Muriel; Van Daele, Sabine; De Baets, Frans; Van Biervliet, Stephanie

    2018-03-01

    Long-term effect of enteral tube feeding (ETF) in cystic fibrosis (CF) remains equivocal. A Belgian CF registry based, retrospective, longitudinal study, evaluated the pre- and post- ETF (n = 113) clinical evolution and compared each patient with 2 age, gender, pancreatic status and genotype class-matched controls. At baseline ETF had a worse BMI z-score (p ETF, had already a significant worse nutritional status and pulmonary function at first entry in the registry. Both parameters displayed a significant decline before ETF-introduction. ETF had more hospitalization and intravenous antibiotic (IVAB) treatment days (p ETF introduction hospitalizations and IVAB decreased significantly. After ETF-introduction BMI z-score recuperated towards the original curve before the decline, but remained below the controls. Starting ETF had no effect on rate of height gain in children. The pre-index FEV1 decline (-1.52%/year (p = 0.002)) stabilized to +0.39%/year afterwards. Controls displayed decline of -0.48%/year (p ETF introduction improved BMI z-score and stabilized FEV1, associated with less hospitalizations and IVAB treatments. Higher mortality and transplantation in the ETF cases, leading to drop-outs, made determination of the effect size difficult. Copyright © 2018 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

  6. Low Apgar score, neonatal encephalopathy and epidural analgesia during labour: a Swedish registry-based study.

    Science.gov (United States)

    Törnell, S; Ekéus, C; Hultin, M; Håkansson, S; Thunberg, J; Högberg, U

    2015-04-01

    Maternal intrapartum fever (MF) is associated with neonatal sequelae, and women in labour who receive epidural analgesia (EA) are more likely to develop hyperthermia. The aims of this study were to investigate if EA and/or a diagnosis of MF were associated to adverse neonatal outcomes at a population level. Population-based register study with data from the Swedish Birth Register and the Swedish National Patient Register, including all nulliparae (n=294,329) with singleton pregnancies who gave birth at term in Sweden 1999-2008. Neonatal outcomes analysed were Apgar score (AS)neonatal encephalopathy (e.g. convulsions or neonatal cerebral ischaemia). Multivariate logistic regression was used to calculate adjusted odds ratios (AOR) with 95% confidence intervals (CI). EA was used in 44% of the deliveries. Low AS or encephalopathy was found in 1.26% and 0.39% of the children in the EA group compared with 0.80% and 0.29% in the control group. In multivariate analysis, EA was associated with increased risk with low AS, AOR 1.27 (95% CI 1.16-1.39), but not with diagnosis of encephalopathy, 1.11 (0.96-1.29). A diagnosis of MF was associated with increased risk for both low AS, 2.27 (1.71-3.02), and of neonatal encephalopathy, 1.97 (1.19-3.26). Diagnosis of MF was associated with low AS and neonatal encephalopathy, whereas EA was only associated with low AS and not with neonatal encephalopathy. The found associations might be a result of confounding by indication, which is difficult to assess in a registry-based population study. © 2015 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  7. "Inclusive working life in Norway": a registry-based five-year follow-up study.

    Science.gov (United States)

    Foss, Line; Gravseth, Hans Magne; Kristensen, Petter; Claussen, Bjørgulf; Mehlum, Ingrid Sivesind; Skyberg, Knut

    2013-07-08

    In 2001, the Norwegian authorities and major labour market partners signed an agreement regarding 'inclusive working life' (IW), whereby companies that participate are committed to reducing sickness absence. Our main aim was to determine the effect of the IW program and work characteristics by gender on long-term (>8 weeks) sickness absence (LSA). Self-reported data on work characteristics from the Oslo Health Study were linked to registry-based data on IW status, education and LSA. From 2001-2005, 10,995 participants (5,706 women and 5,289 men) aged 30, 40, 45 and 60 years were followed. A Cox regression was used to compute hazard ratios (HR) for LSA risk. The cohort was divided into an IW group (2,733 women and 2,058 men) and non-IW group (2,973/3,231). 43.2% and 41.6% of women and 22.3%/24.3% of men (IW / non-IW, respectively) experienced at least one LSA. In a multivariate model, statistically significant risk factors for LSA were low education (stronger in men), shift work/night work or rotating hours (strongest in men in the non-IW group), and heavy physical work or work involving walking and lifting (men only and stronger in the non-IW group). Among men who engaged in shift work, the LSA risk was significantly lower in the IW group. Our results could suggest that IW companies that employ many men in shift work have implemented relevant efforts for reducing sickness absence. However, this study could not demonstrate a significant effect of the IW program on the overall LSA risk.

  8. Maternal Risk Factors for Preterm Birth in Murmansk County, Russia: A Registry-Based Study.

    Science.gov (United States)

    Usynina, Anna A; Postoev, Vitaly A; Grjibovski, Andrej M; Krettek, Alexandra; Nieboer, Evert; Odland, Jon Øyvind; Anda, Erik Eik

    2016-09-01

    Globally, about 11% of all liveborn infants are preterm. To date, data on prevalence and risk factors of preterm birth (PTB) in Russia are limited. The aims of this study were to estimate the prevalence of PTB in Murmansk County, Northwestern Russia and to investigate associations between PTB and selected maternal factors using the Murmansk County Birth Registry. We conducted a registry-based study of 52 806 births (2006-2011). In total, 51 156 births were included in the prevalence analysis, of which 3546 were PTBs. Odds ratios with 95% confidence intervals of moderate-to-late PTB, very PTB and extremely PTB for a range of maternal characteristics were estimated using multinomial logistic regression, adjusting for potential confounders. The overall prevalence of PTB in Murmansk County was 6.9%. Unmarried status, prior PTBs, spontaneous and induced abortions were strongly associated with PTB at any gestational age. Maternal low educational level increased the risk of extremely and moderate-to-late PTB. Young (<18 years) or older (≥35 years) mothers, graduates of vocational schools, underweight, overweight/obese mothers, and smokers were at higher risk of moderate-to-late PTB. Secondary education, alcohol abuse, diabetes mellitus, or gestational diabetes were strongly associated with moderate-to-late and very PTB. The observed prevalence of PTB (6.9%) in Murmansk County, Russia was comparable with data on live PTB from European countries. Adverse prior pregnancy outcomes, maternal low educational level, unmarried status, alcohol abuse, and diabetes mellitus or gestational diabetes were the most common risk factors for PTB. © 2016 John Wiley & Sons Ltd.

  9. Academic performance in adolescents born after ART—a nationwide registry-based cohort study

    DEFF Research Database (Denmark)

    Spangmose, Anne Lærke; Malchau, Sara; Schmidt, Lone

    2017-01-01

    singletons and ART twins. LIMITATIONS, REASONS FOR CAUTION Missing data on educational test scores occurred in 6.6% of adolescents aged 15–16 years for the birth cohorts 1995–1997, where all of the children according to their age should have passed the ninth grade exam at the time of data retrieval......STUDY QUESTION Is academic performance in adolescents aged 15–16 years and conceived after ART, measured as test scores in ninth grade, comparable to that for spontaneously conceived (SC) adolescents? SUMMARY ANSWER ART singletons had a significantly lower mean test score in the adjusted analysis...... are based on national data, our findings can be applied to other populations. The findings of this paper suggest that a possible small negative effect of parental subfertility or ART treatment is counterbalanced by the higher educational level in the ART parents. STUDY FUNDING/COMPETING INTEREST...

  10. Immigrants’ use of emergency primary health care in Norway: a registry-based observational study

    Directory of Open Access Journals (Sweden)

    Sandvik Hogne

    2012-09-01

    Full Text Available Abstract Background Emigrants are often a selected sample and in good health, but migration can have deleterious effects on health. Many immigrant groups report poor health and increased use of health services, and it is often claimed that they tend to use emergency primary health care (EPHC services for non-urgent purposes. The aim of the present study was to analyse immigrants’ use of EPHC, and to analyse variations according to country of origin, reason for immigration, and length of stay in Norway. Methods We conducted a registry based study of all immigrants to Norway, and a subsample of immigrants from Poland, Germany, Iraq and Somalia, and compared them with native Norwegians. The material comprised all electronic compensation claims for EPHC in Norway during 2008. We calculated total contact rates, contact rates for selected diagnostic groups and for services given during consultations. Adjustments for a series of socio-demographic and socio-economic variables were done by multiple logistic regression analyses. Results Immigrants as a whole had a lower contact rate than native Norwegians (23.7% versus 27.4%. Total contact rates for Polish and German immigrants (mostly work immigrants were 11.9% and 7.0%, but for Somalis and Iraqis (mostly asylum seekers 31.8% and 33.6%. Half of all contacts for Somalis and Iraqis were for non-specific pain, and they had relatively more of their contacts during night than other groups. Immigrants’ rates of psychiatric diagnoses were low, but increased with length of stay in Norway. Work immigrants suffered less from respiratory and gastrointestinal infections, but had more injuries and higher need for sickness certification. All immigrant groups, except Germans, were more often given a sickness certificate than native Norwegians. Use of interpreter was reduced with increasing length of stay. All immigrant groups had an increased need for long consultations, while laboratory tests were most often used

  11. Immigrants’ use of emergency primary health care in Norway: a registry-based observational study

    Science.gov (United States)

    2012-01-01

    Background Emigrants are often a selected sample and in good health, but migration can have deleterious effects on health. Many immigrant groups report poor health and increased use of health services, and it is often claimed that they tend to use emergency primary health care (EPHC) services for non-urgent purposes. The aim of the present study was to analyse immigrants’ use of EPHC, and to analyse variations according to country of origin, reason for immigration, and length of stay in Norway. Methods We conducted a registry based study of all immigrants to Norway, and a subsample of immigrants from Poland, Germany, Iraq and Somalia, and compared them with native Norwegians. The material comprised all electronic compensation claims for EPHC in Norway during 2008. We calculated total contact rates, contact rates for selected diagnostic groups and for services given during consultations. Adjustments for a series of socio-demographic and socio-economic variables were done by multiple logistic regression analyses. Results Immigrants as a whole had a lower contact rate than native Norwegians (23.7% versus 27.4%). Total contact rates for Polish and German immigrants (mostly work immigrants) were 11.9% and 7.0%, but for Somalis and Iraqis (mostly asylum seekers) 31.8% and 33.6%. Half of all contacts for Somalis and Iraqis were for non-specific pain, and they had relatively more of their contacts during night than other groups. Immigrants’ rates of psychiatric diagnoses were low, but increased with length of stay in Norway. Work immigrants suffered less from respiratory and gastrointestinal infections, but had more injuries and higher need for sickness certification. All immigrant groups, except Germans, were more often given a sickness certificate than native Norwegians. Use of interpreter was reduced with increasing length of stay. All immigrant groups had an increased need for long consultations, while laboratory tests were most often used for Somalis and Iraqis

  12. Musical Interests and Talent: Twin Jazz Musicians and Twin Studies/Twin Research: Loss of a Preterm Multiple; Conjoined Twin Conception; Depression in Fathers of Twins; Twin-to-Twin Transfusion Syndrome/Twin News: High-Achieving Twins; Twin Children of a Tennis Star; Conjoined Twin Separation; Twin Delivery to a Giant Panda.

    Science.gov (United States)

    Segal, Nancy L

    2017-12-01

    Findings from twin studies of musical interests and talent are reviewed as a backdrop to the lives and careers of twin jazz musicians, Peter and Will Anderson. The Anderson twins exemplify many aspects of twin research, namely their matched musical abilities, shared musical interests, and common career. This overview is followed by reviews of studies and case reports of bereavement in families who have lost a preterm multiple birth infant, the conception of conjoined twins following in vitro fertilization (IVF), depression in fathers of twins, and twin-to-twin transfusion incidence in monochorionic-diamniotic IVF twin pairs. Twins highlighted in the media include high-achieving identical female twins with nearly identical academic standing, tennis star Roger Federer's two sets of identical twin children, surgical separation of craniopagus conjoined twins, and the rare delivery of twins to a 23-year-old giant panda.

  13. Twin Studies of Atopic Dermatitis

    DEFF Research Database (Denmark)

    Elmose, Camilla; Thomsen, Simon Francis

    2015-01-01

    Aim. The aim of this study was to conduct a systematic review of population-based twin studies of (a) the concordance and heritability of AD and (b) the relationship between AD and asthma and, furthermore, to reinterpret findings from previous twin studies in the light of the emerging knowledge a...

  14. Preeclampsia complicated by advanced maternal age: a registry-based study on primiparous women in Finland 1997–2008

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    Lamminpää Reeta

    2012-06-01

    Full Text Available Abstract Background Preeclampsia is a frequent syndrome and its cause has been linked to multiple factors, making prevention of the syndrome a continuous challenge. One of the suggested risk factors for preeclampsia is advanced maternal age. In the Western countries, maternal age at first delivery has been steadily increasing, yet few studies have examined women of advanced maternal age with preeclampsia. The purpose of this registry-based study was to compare the obstetric outcomes in primiparous and preeclamptic women younger and older than 35 years. Methods The registry-based study used data from three Finnish health registries: Finnish Medical Birth Register, Finnish Hospital Discharge Register and Register of Congenital Malformations. The sample contained women under 35 years of age (N = 15,437 compared with those 35 and over (N = 2,387 who were diagnosed with preeclampsia and had their first singleton birth in Finland between 1997 and 2008. In multivariate modeling, the main outcome measures were Preterm delivery (before 34 and 37 weeks, low Apgar score (5 min., small-for-gestational-age, fetal death, asphyxia, Cesarean delivery, induction, blood transfusion and admission to a Neonatal Intensive Care Unit. Results Women of advanced maternal age (AMA exhibited more preeclampsia (9.4% than younger women (6.4%. They had more prior terminations (25 ( Conclusions Preeclampsia is more common in women with advanced maternal age. Advanced maternal age is an independent risk factor for adverse outcomes in first-time mothers with preeclampsia.

  15. Occupational risk factors for testicular cancer: a registry-based case-control study in Rhineland Palatinate – Germany

    Science.gov (United States)

    Yousif, Lamyaa; Hammer, Gaël P.; Emrich, Katharina; Blettner, Maria; Zeeb, Hajo

    2013-01-01

    Objectives: Testicular cancer affects mainly men below the age of 50. An association with occupation and social status has been suggested but risk factors are not well understood. A registry-based case-control study focusing on occupation was performed in Germany. Methods: All 348 testicular cancer cases with available gainful occupational information registered between 2000 and 2005; as well as 564 suitable controls (from a pool of other cancers) were drawn from the Cancer Registry of Rhineland-Palatinate. Unconditional logistic regression was used to compute odds ratios (OR) and associated 95% confidence intervals (CI). Results: Slightly elevated OR were observed for technicians and related professionals (OR 1.62, 95% CI 1.00–2.63) and for clerical support workers (OR 1.71, 95% CI 1.14–2.56). This increase was highest in the age group 20–50 for technicians (OR 2.02, 95% CI 1.23–3.33) and clerks (OR 2.00, 95% CI 1.30–3.09), respectively. An association with testicular cancer was observed for no other occupation. Conclusion: An increased risk of testicular cancer was observed for technicians and related professionals and clerical support workers. This could be related to socioeconomic status or sedentary life style, two factors that were identified in previous studies. While the feasibility of a purely registry-based study was shown, missing occupational data and the choice of cancer controls represent challenges to the validity of this approach. PMID:24265602

  16. The USC Adult Twin Cohorts: International Twin Study and California Twin Program.

    Science.gov (United States)

    Cozen, Wendy; Hwang, Amie E; Cockburn, Myles G; Hamilton, Ann S; Zadnick, John; Mack, Thomas M

    2013-02-01

    The study of twin subjects permits the documentation of crude heritability and may promote the identification of specific causal alleles. We believe that at the current time, the chief research advantage of twins as subjects, especially monozygotic twins, is that the commonality of their genetic and cultural identity simplifies the interpretation of biological associations. In order to study genetic and environmental determinants of cancer and chronic diseases, we developed two twin registries, maintained at the University of Southern California: The International Twin Study (ITS) and the California Twin Program (CTP). The ITS is a volunteer registry of twins with cancer and chronic disease consisting of 17,245 twin pairs affected by cancer and chronic disease, respectively, ascertained by advertising in periodicals from 1980-1991. The CTP is a population-based registry of California-born twin pairs ascertained by linking the California birth records to the State Department of Motor Vehicles. Over 51,000 individual California twins representing 36,965 pairs completed and returned 16-page questionnaires. Cancer diagnoses in the California twins are updated by regular linkage to the California Cancer Registry. Over 5,000 cancer patients are represented in the CTP. Twins from both registries have participated extensively in studies of breast cancer, melanoma, lymphoma, multiple sclerosis, systemic lupus erythematosus, diabetes mellitus type 1, mammographic density, smoking, and other traits and conditions.

  17. The classical twin study and beyond

    NARCIS (Netherlands)

    Boomsma, D.I.; Busjahn, A.; Peltonen, L.

    2002-01-01

    Twin studies have been a valuable source of information about the genetic basis of complex traits. To maximize the potential of twin studies, large, worldwide registers of data on twins and their relatives have been established. Here, we provide an overview of the current resources for twin

  18. Socioeconomic Inequalities in the Kidney Transplantation Process: A Registry-Based Study in Sweden

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    Ye Zhang, MSc

    2018-02-01

    Conclusions. Socioeconomic status-related inequalities exist with regard to both access to the waitlist, and kidney transplantation conditional on listing. However, the former inequality is substantially larger and is therefore expected to contribute more to societal inequalities. Further studies are needed to explore the potential mechanisms and strategies to reduce these inequalities.

  19. Folic acid supplementation influences the distribution of neural tube defect subtypes : A registry-based study

    NARCIS (Netherlands)

    Bergman, J. E. H.; Otten, E.; Verheij, J. B. G. M.; de Walle, H. E. K.

    Periconceptional folic acid (FA) reduces neural tube defect (NTD) risk, but seems to have a varying effect per NTD subtype. We aimed to study the effect of FA supplementation on NTD subtype distribution using data from EUROCAT Northern Netherlands. We included all birth types with non-syndromal NTDs

  20. A nationwide registry-based cohort study of incidence of tonsillectomy in Denmark, 1991-2012

    DEFF Research Database (Denmark)

    Juul, Marie Louise; Rasmussen, Eva Rye; Rasmussen, Stig Hebbelstrup Rye

    2018-01-01

    OBJECTIVE: To update tonsillectomy incidence rates in Denmark and identify whether the incidence rates vary between geographical areas in the country during the period 1991-2012. DESIGN: This was a retrospective nationwide cohort study using data from the comprehensive Danish patient registries. ...

  1. Temporal Trends in Fertility Rates: A Nationwide Registry Based Study from 1901 to 2014

    OpenAIRE

    Blomberg Jensen, Martin; Priskorn, L?rke; Jensen, Tina Kold; Juul, Anders; Skakkebaek, Niels Erik

    2015-01-01

    Objective Increasing age at first childbirth has been suggested to increase the risk for infertility. Our objective is to determine whether women above thirty years of age historically have been able to sustain fertility rates above replacement level. Design A descriptive nationwide Danish study using birth registries from 1901?2014. Setting Information on women?s age at childbirth was obtained by using records from primary, secondary and tertiary institutions. Participants Mothers to 8,024,9...

  2. The Impact of Diagnosis on Job Retention: A Danish Registry-Based Cohort Study

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    Rasmus Espersen

    2015-01-01

    Full Text Available Background. In 1998, Denmark introduced the flex job scheme to ensure employment of people with a permanent reduced work capacity. This study investigated the association between select diagnoses and the risk of disability pension among persons eligible for the scheme. Methods. Using the national DREAM database we identified all persons eligible for the flex job scheme from 2001 to 2008. This information piece was linked to the hospital discharge registry. Selected participants were followed for 5 years. Results. From the 72,629 persons identified, our study included 329 patients with rheumatoid arthritis, 10,120 patients with spine disorders, 2179 patients with ischemic heart disease, and 1765 patients with functional disorders. A reduced risk of disability pension was found in the group with rheumatoid arthritis (hazard ratio = 0.69 (0.53–0.90 compared to the group with spine disorders. No differences were found when comparing ischemic heart disease and functional disorders. Employment during the first 3 months of the flex job scheme increased the degree of employment for all groups. Conclusion. Differences in the risk of disability pension were identified only in patients with rheumatoid arthritis. This study demonstrates the importance of obtaining employment immediately after allocation to the flex job scheme, regardless of diagnosis.

  3. Prescription medicines and the risk of road traffic crashes: a French registry-based study.

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    Ludivine Orriols

    2010-11-01

    Full Text Available In recent decades, increased attention has been focused on the impact of disabilities and medicinal drug use on road safety. The aim of our study was to investigate the association between prescription medicines and the risk of road traffic crashes, and estimate the attributable fraction.We extracted and matched data from three French nationwide databases: the national health care insurance database, police reports, and the national police database of injurious crashes. Drivers identified by their national health care number involved in an injurious crash in France, between July 2005 and May 2008, were included in the study. Medicines were grouped according to the four risk levels of the French classification system (from 0 [no risk] to 3 [high risk]. We included 72,685 drivers involved in injurious crashes. Users of level 2 (odds ratio [OR]  = 1.31 [1.24-1.40] and level 3 (OR  = 1.25 [1.12-1.40] prescription medicines were at higher risk of being responsible for a crash. The association remained after adjustment for the presence of a long-term chronic disease. The fraction of road traffic crashes attributable to levels 2 and 3 medications was 3.3% [2.7%-3.9%]. A within-person case-crossover analysis showed that drivers were more likely to be exposed to level 3 medications on the crash day than on a control day, 30 days earlier (OR  = 1.15 [1.05-1.27].The use of prescription medicines is associated with a substantial number of road traffic crashes in France. In light of the results, warning messages appear to be relevant for level 2 and 3 medications and questionable for level 1 medications. A follow-up study is needed to evaluate the impact of the warning labeling system on road traffic crash prevention.

  4. Long-term sickness absence from work due to physical inactivity: A registry-based study.

    Science.gov (United States)

    Høgsbro, Cecilie; Davidsen, Michael; Sørensen, Jan

    2018-01-01

    The aim of this study was to explore the relationship between leisure-time physical inactivity and long-term sickness absence in a representative sample of individuals aged 16-54 years, within the labour market and in good health. It was hypothesised that physically inactive individuals have a higher risk of long-term sickness absence and longer duration of sickness absence. The study population was identified from the National Health and Morbidity Survey, 2010. Weekly data on long-term sickness absence were obtained from the National Register on Social Transfer Payments (the DREAM registry). The association of incidence and duration of long-term sickness absence with physical inactivity was explored using logistic and Poisson regression. Data were fitted to models with levels of physical activity, demographic, social and lifestyle characteristics as independent variables. A combined hurdle model was used to estimate the difference in mean number of absence weeks. Logistic regression showed that physically inactive individuals had a 27% higher incidence of long-term sickness absence compared with physically active individuals. The Poisson regression showed that long-term sickness absence was only slightly shorter (1 week less) for moderately active individuals compared with inactive individuals. The hurdle model estimated longer absence periods for inactive individuals (additional 2.5 weeks) in comparison with moderately and highly active individuals. The study showed that physically inactive individuals have a higher incidence of long-term absence and that physically inactive individuals have longer periods with sickness absence than moderately and highly active individuals. When adjustments for social and health behaviour were included, the estimated associations became statistically insignificant.

  5. A Nation-Wide Cancer Registry-Based Study of Adenosquamous Carcinoma in Taiwan.

    Directory of Open Access Journals (Sweden)

    Yuan-Tzu Lan

    Full Text Available Adenosquamous carcinoma (ASC is a rare disease involving various organs, yet there are no large-scale population-based comparative studies on ASC among different organs.The incidence and overall survival of ASC among various organs in cases diagnosed in Taiwan from January 1, 2003 to December 31, 2010 were calculated and compared using data from the Taiwan Cancer Registry (TCR. The various organs were classified and divided into three different systems: the female reproductive, respiratory, and alimentary systems. Survival analysis were also compared among 30,850 patients diagnosed as ASC, adenocarcinoma (AC or squamous cell carcinoma (SCC in organs with frequent ASC.During the study period, a total of 576 ASC cases were diagnosed in Taiwan. The most common primary system was respiratory (73.8%, followed by alimentary (16.2% and female reproductive (10%. The overall survival were significantly higher for cases involving the female reproductive system, followed by the respiratory and alimentary systems (P = 0.016. The median overall survival were worse in males than females for cases involving the respiratory system (22.4 vs. 31.8 months, P = 0.044. Multivariate analysis showed that age ≧ 65, more advanced T and N categories were independent unfavorable prognostic factors of overall survival in ASC. ASC histology is an independent unfavorable prognostic factor compared with AC and SCC.ASC at an old age and more advanced T and N categories were found to be associated with a poor prognosis.

  6. A Nation-Wide Cancer Registry-Based Study of Adenosquamous Carcinoma in Taiwan

    Science.gov (United States)

    Lan, Yuan-Tzu; Huang, Kuo-Hung; Liu, Chien-An; Tai, Ling-Chen; Chen, Ming-Huang; Chao, Yee; Li, Anna Fen-Yau; Chiou, Shih-Hwa; Shyr, Yi-Ming; Wu, Chew-Wun; Fang, Wen-Liang

    2015-01-01

    Background Adenosqamous carcinoma (ASC) is a rare disease involving various organs, yet there are no large-scale population-based comparative studies on ASC among different organs. Methods The incidence and overall survival of ASC among various organs in cases diagnosed in Taiwan from January 1, 2003 to December 31, 2010 were calculated and compared using data from the Taiwan Cancer Registry (TCR). The various organs were classified and divided into three different systems: the female reproductive, respiratory, and alimentary systems. Survival analysis were also compared among 30,850 patients diagnosed as ASC, adenocarcinoma (AC) or squamous cell carcinoma (SCC) in organs with frequent ASC. Results During the study period, a total of 576 ASC cases were diagnosed in Taiwan. The most common primary system was respiratory (73.8%), followed by alimentary (16.2%) and female reproductive (10%). The overall survival were significantly higher for cases involving the female reproductive system, followed by the respiratory and alimentary systems (P = 0.016). The median overall survival were worse in males than females for cases involving the respiratory system (22.4 vs. 31.8 months, P = 0.044). Multivariate analysis showed that age≧65, more advanced T and N categories were independent unfavorable prognostic factors of overall survival in ASC. ASC histology is an independent unfavorable prognostic factor compared with AC and SCC. Conclusions ASC at an old age and more advanced T and N categories were found to be associated with a poor prognosis. PMID:26445240

  7. Cancer in ANCA-Associated Glomerulonephritis: A Registry-Based Cohort Study

    Directory of Open Access Journals (Sweden)

    Sanjeevan Sriskandarajah

    2017-01-01

    Full Text Available Background. Immunosuppressive therapy for antineutrophil cytoplasmic antibody-associated vasculitis has been associated with increased malignancy risk. Objectives. To quantify the cancer risk associated with contemporary cyclophosphamide-sparing protocols. Methods. Patients from the Norwegian Kidney Biopsy Registry between 1988 and 2012 who had biopsy-verified pauci-immune glomerulonephritis and positive antineutrophil cytoplasmic antibody (ANCA serology were included. Standardised incidence ratios (SIRs were calculated to compare the study cohort with the general population. Results. The study cohort included 419 patients. During 3010 person-years, cancer developed in 41 patients (9.79%; the expected number of cancer cases was 37.5 (8.95%. The cohort had SIRs as follows: 1.09, all cancer types (95% CI, 0.81 to 1.49; 0.96, all types except nonmelanoma skin cancer (95% CI, 0.69 to 1.34; 3.40, nonmelanoma skin cancer (95% CI, 1.62 to 7.14; 3.52, hematologic cancer (95% CI, 1.32 to 9.37; 2.12, posttransplant cancer (95% CI, 1.01 to 4.44; and 1.53, during the 1–5-year follow-up after diagnosis (95% CI, 1.01 to 2.32. Conclusions. Cancer risk did not increase significantly in this cohort with ANCA-associated glomerulonephritis. However, increased risk of nonmelanoma skin cancer, posttransplant cancer, and hematologic cancer indicates an association between immunosuppression and malignancy.

  8. Temporal Trends in Fertility Rates: A Nationwide Registry Based Study from 1901 to 2014.

    Science.gov (United States)

    Blomberg Jensen, Martin; Priskorn, Lærke; Jensen, Tina Kold; Juul, Anders; Skakkebaek, Niels Erik

    2015-01-01

    Increasing age at first childbirth has been suggested to increase the risk for infertility. Our objective is to determine whether women above thirty years of age historically have been able to sustain fertility rates above replacement level. A descriptive nationwide Danish study using birth registries from 1901-2014. Information on women's age at childbirth was obtained by using records from primary, secondary and tertiary institutions. Mothers to 8,024,969 live births. Mothers were stratified according to age at childbirth to determine total and age specific fertility rates. Total fertility rate (TFR) decreased from 4.1 to 1.8 children per woman and age specific fertility also decreased from 1901 to 2014. Women aged 30-34, 35-39 or 40-44 years in the first decade of the 20th century had higher fertility rates than the corresponding five year younger age groups (25-29, 30-34 and 35-39, respectively) have had for the last 65 years. On average, women gave birth to two children after the age of 30 and one or more child after 35 years of age in the beginning of the 1900s. Furthermore, women more than 40 years of age accounted for 10% of TFR in 1901 compared with 4% in 2014 despite usage of assisted reproduction. This nationwide study shows that women above 30 years of age historically have been able to sustain fertility rates above replacement level. This implies that other factors besides age are strong determinants of fertility in women above 30 years of age.

  9. Transfer of newborns to neonatal care unit: a registry based study in Northern Tanzania

    Directory of Open Access Journals (Sweden)

    Kibiki Gibson S

    2011-10-01

    Full Text Available Abstract Background Reduction in neonatal mortality has been slower than anticipated in many low income countries including Tanzania. Adequate neonatal care may contribute to reduced mortality. We studied factors associated with transfer of babies to a neonatal care unit (NCU in data from a birth registry at Kilimanjaro Christian Medical Centre (KCMC in Tanzania. Methods A total of 21 206 singleton live births registered from 2000 to 2008 were included. Multivariable analysis was carried out to study neonatal transfer to NCU by socio-demographic factors, pregnancy complications and measures of the condition of the newborn. Results A total of 3190 (15% newborn singletons were transferred to the NCU. As expected, neonatal transfer was strongly associated with specific conditions of the baby including birth weight above 4000 g (relative risk (RR = 7.2; 95% confidence interval (CI 6.5-8.0 or below 1500 g (RR = 3.0; 95% CI: 2.3-4.0, five minutes Apgar score less than 7 (RR = 4.0; 95% CI: 3.4-4.6, and preterm birth before 34 weeks of gestation (RR = 1.8; 95% CI: 1.5-2.1. However, pregnancy- and delivery-related conditions like premature rupture of membrane (RR = 2.3; 95% CI: 1.9-2.7, preeclampsia (RR = 1.3; 95% CI: 1.1-1.5, other vaginal delivery (RR = 2.2; 95% CI: 1.7-2.9 and caesarean section (RR = 1.9; 95% CI: 1.8-2.1 were also significantly associated with transfer. Birth to a first born child was associated with increased likelihood of transfer (relative risk (RR 1.4; 95% CI: 1.2-1.5, while the likelihood was reduced (RR = 0.5; 95% CI: 0.3-0.9 when the father had no education. Conclusions In addition to strong associations between neonatal transfer and classical neonatal risk factors for morbidity and mortality, some pregnancy-related and demographic factors were predictors of neonatal transfer. Overall, transfer was more likely for babies with signs of poor health status or a complicated pregnancy. Except for a possibly reduced use of transfer

  10. Sarcoidosis in Denmark 1980-1994. A registry-based incidence study comprising 5536 patients

    DEFF Research Database (Denmark)

    Byg, Keld-Erik; Milman, Nils; Hansen, Stig

    2003-01-01

    BACKGROUND AND AIM: To evaluate the incidence of sarcoidosis in Denmark 1980-1994. METHODS: Patients with a diagnosis of sarcoidosis were identified from the Danish National Patient Registry. The file contained information about the year in which the diagnosis was reported, gender, age, and resid......BACKGROUND AND AIM: To evaluate the incidence of sarcoidosis in Denmark 1980-1994. METHODS: Patients with a diagnosis of sarcoidosis were identified from the Danish National Patient Registry. The file contained information about the year in which the diagnosis was reported, gender, age......, and residential county. RESULTS: 5536 persons (2816 men) with sarcoidosis were registered. Median age in men was 38 years, in women 45 years. The male/female incidence ratio was 1.06. The incidence (per 100,000 person years) declined gradually from 8.1 in 1980-1984 to 6.4 in 1990-1994. The overall incidence...... (11.0). CONCLUSION: Incidence rates in the present study are lower compared with previous mass-screening surveys showing an incidence rate of 13.8 (in persons examined). Peak incidences occurred at higher ages in both men and women. Previous surveys showed peak incidences at 20-25 years in men...

  11. The quest for a universal definition of polytrauma: a trauma registry-based validation study.

    Science.gov (United States)

    Butcher, Nerida E; D'Este, Catherine; Balogh, Zsolt J

    2014-10-01

    A pilot validation recommended defining polytrauma as patients with an Abbreviated Injury Scale (AIS) score greater than 2 in at least two Injury Severity Score (ISS) body regions (2 × AIS score > 2). This study aimed to validate this definition on larger data set. We hypothesized that patients defined by the 2 × AIS score > 2 cutoff have worse outcomes and use more resources than those without 2 × AIS score > 2 and that this would therefore be a better definition of polytrauma. Patients injured between 2009 and 2011, with complete documentation of AIS by New South Wales Trauma Registry and 16 years and older were selected. Age and sex were obtained in addition to outcomes of ISS, hospital length of stay (LOS), intensive care unit (ICU) admission, ICU LOS, and mortality. We compared demographic characteristics and outcomes between patients with ISS greater than 15 who did and did not meet the 2 × AIS score > 2 definition. We then undertook regression analyses (logistic regression for binary outcomes [ICU admission and death] and linear regression for hospital and ICU LOS) to compare outcomes for patients with and without 2 × AIS score > 2, adjusting for sex and age categories. In the adjusted analyses, patients with 2 × AIS score > 2 had twice the odds of being admitted to the ICU compared with those without 2 × AIS score > 2 (odds ratio, 2.5; 95% confidence interval [CI], 2.2-2.8) and 1.7 times the odds of dying (95% CI, 1.4-2.0; p 2 also had a mean difference of 1.5 days longer stay in the hospital compared with those without 2 × AIS score > 2 (95% CI, 1.4-1.7) and 1.6 days longer ICU stay (95% CI, 1.4-1.8; p 2 had higher mortality, more frequent ICU admissions, and longer hospital and ICU stay than those without 2 × AIS score > 2 and represents a superior definition to the definitions for polytrauma currently in use. Diagnostic test/ criteria, level III.

  12. Brazilian Twin Registry: A Bright Future for Twin Studies/Twin Research: Twin Study of Alcohol Consumption and Mortality; Oxygen Uptake in Adolescent Twins/In the News: Superfecundated Twins In Vietnam; Adolescent Twin Relations; Twin and Triplet Co-Workers; A Special Twin Ultrasound; Monozygotic Twins With Different Skin Color; Identical Twin Returns from Space.

    Science.gov (United States)

    Segal, Nancy L

    2016-06-01

    The establishment of the Brazilian Twin Registry for the study of genetic, social, and cultural influences on behavior is one of eleven newly funded projects in the Department of Psychology at the University of São Paulo. These 11 interrelated projects form the core of the university's Center for Applied Research on Well-Being and Human Behavior. An overview of the planned twin research and activities to date is presented. Next, two recent twin studies are reviewed, one on the relationship between alcohol consumption and mortality, and the other on factors affecting maximal oxygen uptake. Twins cited in the media include the first identified superfecundated twins in Vietnam, adolescent twin relations, twins and triplets who work together, monozygotic twins with different skin tones and a co-twin control study that addresses the effects of space travel.

  13. Prevalence, prenatal diagnosis and clinical features of oculo-auriculo-vertebral spectrum: a registry-based study in Europe.

    LENUS (Irish Health Repository)

    Barisic, Ingeborg

    2014-01-08

    Oculo-auriculo-vertebral spectrum is a complex developmental disorder characterised mainly by anomalies of the ear, hemifacial microsomia, epibulbar dermoids and vertebral anomalies. The aetiology is largely unknown, and the epidemiological data are limited and inconsistent. We present the largest population-based epidemiological study to date, using data provided by the large network of congenital anomalies registries in Europe. The study population included infants diagnosed with oculo-auriculo-vertebral spectrum during the 1990-2009 period from 34 registries active in 16 European countries. Of the 355 infants diagnosed with oculo-auriculo-vertebral spectrum, there were 95.8% (340\\/355) live born, 0.8% (3\\/355) fetal deaths, 3.4% (12\\/355) terminations of pregnancy for fetal anomaly and 1.5% (5\\/340) neonatal deaths. In 18.9%, there was prenatal detection of anomaly\\/anomalies associated with oculo-auriculo-vertebral spectrum, 69.7% were diagnosed at birth, 3.9% in the first week of life and 6.1% within 1 year of life. Microtia (88.8%), hemifacial microsomia (49.0%) and ear tags (44.4%) were the most frequent anomalies, followed by atresia\\/stenosis of external auditory canal (25.1%), diverse vertebral (24.3%) and eye (24.3%) anomalies. There was a high rate (69.5%) of associated anomalies of other organs\\/systems. The most common were congenital heart defects present in 27.8% of patients. The prevalence of oculo-auriculo-vertebral spectrum, defined as microtia\\/ear anomalies and at least one major characteristic anomaly, was 3.8 per 100 000 births. Twinning, assisted reproductive techniques and maternal pre-pregnancy diabetes were confirmed as risk factors. The high rate of different associated anomalies points to the need of performing an early ultrasound screening in all infants born with this disorder.European Journal of Human Genetics advance online publication, 8 January 2014; doi:10.1038\\/ejhg.2013.287.

  14. Pre-vaccination care-seeking in females reporting severe adverse reactions to HPV vaccine. A registry based case-control study

    DEFF Research Database (Denmark)

    Mølbak, Kåre; Hansen, Niels Dalum; Valentiner-Branth, Palle

    2016-01-01

    to the DMA of suspected severe adverse reactions.We selected controls without reports of adverse reactions from the Danish vaccination registry and matched by year of vaccination, age of vaccination, and municipality, and obtained from the Danish National Patient Registry and The National Health Insurance...... vaccination programme has declined. The aim of the present study was to determine health care-seeking prior to the first HPV vaccination among females who suspected adverse reactions to HPV vaccine. Methods In this registry-based case-control study, we included as cases vaccinated females with reports...... Service Register the history of health care usage two years prior to the first vaccine. We analysed the data by logistic regression while adjusting for the matching variables. Results The study included 316 cases who received first HPV vaccine between 2006 and 2014. Age range of cases was 11 to 52 years...

  15. Exploring The Association Between Severe Respiratory Syncytial Virus Infection and Asthma: a Registry-Based Twin Study

    DEFF Research Database (Denmark)

    Thomsen, Simon Francis; Sluis, Sophie V D; Stensballe, Lone G

    2009-01-01

    ) and linked to information on asthma obtained from hospital discharge registries and parent-completed questionnaires. Genetic variance components models and direction of causation models were fitted to the observed data. RESULTS: RSV hospitalization and asthma were positively associated (r=0.43) and genetic...

  16. Increasing trends in childlessness in recent birth cohorts - a registry-based study of the total Danish male population born from 1945 to 1980

    DEFF Research Database (Denmark)

    Priskorn, L; Holmboe, Sarah; Jacobsen, R

    2012-01-01

    The fertility rate has recently declined in many parts of the World, including Europe. To a large extent, this change can be explained by the socio-economic development. However, increasing fertility problems and widespread occurrence of poor semen quality could in part explain the few births....... The objective of this registry based study was to investigate birth cohort related trends in fertility and childlessness among Danish men. The study population comprised all 1 616 677 men in Denmark born from 1945 to 1980 of whom 1 359 975 (84.1%) were native Danes. Data were obtained from Statistics Denmark...... and contained information from The National Danish Birth Registry and The Danish In Vitro Fertilization (IVF) Registry. For consecutive birth cohorts of native Danish men cumulative fertility rates at age 45 declined from 1.91 children per man in the 1945 birth cohort to 1.71 for men born in 1960...

  17. Cooperative Research Twin Trawl Sweep Comparison Study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The "Twin-Trawl Sweep Efficiency Study" was intended to compare the sweep efficiency and selectivity of the NEFSC standardized bottom trawl to that of a standardized...

  18. Twin methodology in epigenetic studies

    DEFF Research Database (Denmark)

    Tan, Qihua; Christiansen, Lene; von Bornemann Hjelmborg, Jacob

    2015-01-01

    of diseases to molecular phenotypes in functional genomics especially in epigenetics, a thriving field of research that concerns the environmental regulation of gene expression through DNA methylation, histone modification, microRNA and long non-coding RNA expression, etc. The application of the twin method...

  19. The Danish political twin study

    DEFF Research Database (Denmark)

    Klemmensen, Robert; Hobolt, Sara B; Dinesen, Peter Thisted

    2012-01-01

    We compare a recent Danish twin survey on political attitudes and behaviors to a nationally representative survey covering similar topics. We find very similar means and variances for most of our constructed scales of political attitudes and behaviors in the two surveys, although even small...

  20. Remembering Irving I. Gottesman: Twin Research Colleague and Friend Extraordinaire/Research Studies: Face-Lift Technique Comparison in Identical Twins; Raising Preterm Twins; Fetal Behavior in Dichorionic Twin Pregnancies; Co-Bedding and Stress Reduction in Twins/Public Interest: Identical Co-Twins' Same Day Delivery; Teaching Twins in Bosnia; Twin Auctioneers; Sister, the Play.

    Science.gov (United States)

    Segal, Nancy L

    2016-12-01

    Dr Irving I. Gottesman, a colleague, friend, and long-time member of the International Society of Twin Studies passed away on June 29, 2016. His contributions to twin research and some personal reflections are presented to honor both the man and the memory. This tribute is followed by short reviews of twin research concerning differences between cosmetic surgical techniques, the rearing of preterm twins, behavioral observations of dichorionic fetal twins, and the outcomes of co-bedding twins with reference to stress reduction. Interesting and informative articles in the media describe identical co-twins who delivered infants on the same day, educational policies regarding twins in Bosnia and the United Kingdom, unusual practices of twin auctioneers, and a theatrical production, Sister, featuring identical twins in the leading roles.

  1. The Project TALENT Twin and Sibling Study.

    Science.gov (United States)

    Prescott, Carol A; Achorn, Deanna Lyter; Kaiser, Ashley; Mitchell, Lindsey; McArdle, John J; Lapham, Susan J

    2013-02-01

    Project TALENT is a US national longitudinal study of about 377,000 individuals born in 1942-1946, first assessed in 1960. Students in about 1,200 schools participated in a 2-day battery covering aptitudes, abilities, interests, and individual and family characteristics (Flanagan, 1962; www.projectTALENT.org). Follow-up assessments 1, 5, and 11 years later assessed educational and occupational outcomes. The sample includes approximately 92,000 siblings from 40,000 families, including 2,500 twin pairs and 1,200 other siblings of twins. Until recently, almost no behavior genetic research has been conducted with the sample. In the original data collection information was not collected with the intent to link family members. Recently, we developed algorithms using names, addresses, birthdates, and information about family structure to link siblings and identify twins. We are testing several methods to determine zygosity, including use of yearbook photographs. In this paper, we summarize the design and measures in Project TALENT, describe the Twin and Sibling sample, and present our twin-sib-classmate model. In most twin and family designs, the 'shared environment' includes factors specific to the family combined with between-family differences associated with macro-level variables such as socioeconomic status. The school-based sampling design used in Project TALENT provides a unique opportunity to partition the shared environment into variation shared by siblings, specific to twins, and associated with school- and community-level factors. The availability of many measured characteristics on the family, schools, and neighborhoods enhances the ability to study the impact of specific factors on behavioral variation.

  2. A twin study of body dysmorphic concerns.

    Science.gov (United States)

    Monzani, B; Rijsdijk, F; Anson, M; Iervolino, A C; Cherkas, L; Spector, T; Mataix-Cols, D

    2012-09-01

    Dysmorphic concern refers to an excessive preoccupation with a perceived or slight defect in physical appearance. It lies on a continuum of severity from no or minimal concerns to severe concerns over one's appearance. The present study examined the heritability of dysmorphic concerns in a large sample of twins. Twins from the St Thomas UK twin registry completed a valid and reliable self-report measure of dysmorphic concerns, which also includes questions about perceived body odour and malfunction. Twin modelling methods (female twins only, n=3544) were employed to decompose the variance in the liability to dysmorphic concerns into additive genetic, shared and non-shared environmental factors. Model-fitting analyses showed that genetic factors accounted for approximately 44% [95% confidence intervals (CI) 36-50%] of the variance in dysmorphic concerns, with non-shared environmental factors and measurement error accounting for the remaining variance (56%; 95% CI 50-63%). Shared environmental factors were negligible. The results remained unchanged when excluding individuals reporting an objective medical condition/injury accounting for their concern in physical appearance. Over-concern with a perceived or slight defect in physical appearance is a heritable trait, with non-shared environmental factors also playing an important role in its causation. The results are relevant for various psychiatric disorders characterized by excessive concerns in body appearance, odour or function, including but not limited to body dysmorphic disorder.

  3. Migrant breast cancer patients and their participation in genetic counseling : results from a registry-based study

    NARCIS (Netherlands)

    Baars, J E; van Dulmen, A M; Velthuizen, M E; Theunissen, E B M; Vrouenraets, B C; Kimmings, A N; van Dalen, T; van Ooijen, B; Witkamp, A J; van der Aa, M A; Ausems, M G E M

    Certain ethnic groups seem to have less access to cancer genetic counseling. Our study was to investigate the participation in cancer genetic counseling among migrant breast cancer patients of Turkish and Moroccan origin. Hospital medical records of Turkish and Moroccan and of a comparative group of

  4. Migrant breast cancer patients and their participation in genetic counseling: results from a registry-based study.

    NARCIS (Netherlands)

    Baars, J.E.; Dulmen, A.M. van; Velthuizen, M.E.; Theunissen, E.B.M.; Vrouenraets, B.C.; Kimmings, A.N.; Dalen, T. van; Ooijen, B. van; Witkamp, A.J.; Aa, M.A. van der; Ausems, M.G.E.M.

    2016-01-01

    Certain ethnic groups seem to have less access to cancer genetic counseling. Our study was to investigate the participation in cancer genetic counseling among migrant breast cancer patients of Turkish and Moroccan origin. Hospital medical records of Turkish and Moroccan and of a comparative group of

  5. Migrant breast cancer patients and their participation in genetic counseling: results from a registry-based study

    NARCIS (Netherlands)

    Baars, J.E.; Dulmen, A.M. van; Velthuizen, M.E.; Theunissen, E.B.; Vrouenraets, B.C.; Kimmings, A.N.; Dalen, T. van; Ooijen, B. van; Witkamp, A.J.; Aa, M.A. van der; Ausems, M.G.

    2016-01-01

    Certain ethnic groups seem to have less access to cancer genetic counseling. Our study was to investigate the participation in cancer genetic counseling among migrant breast cancer patients of Turkish and Moroccan origin. Hospital medical records of Turkish and Moroccan and of a comparative group of

  6. Increasing Incidence of Hospitalization for Stroke and Transient Ischemic Attack in Young Adults: A Registry-Based Study.

    Science.gov (United States)

    Tibæk, Maiken; Dehlendorff, Christian; Jørgensen, Henrik S; Forchhammer, Hysse B; Johnsen, Søren P; Kammersgaard, Lars P

    2016-05-11

    Studies have reported increasing incidence of ischemic stroke in adults younger than 50 to 55 years. Information on temporal trends of other stroke subtypes and transient ischemic attack (TIA) is sparse. The aim of this study was to investigate temporal trends of the incidence of hospitalizations for TIA and stroke including sex- and subtype-specific trends in young adults aged 15 to 30 years. From the Danish National Patient Register, we identified all cases of first-ever stroke and TIA (age 15-30 years) in Denmark, who were hospitalized during the study period of 1994 to 2012. Incidence rates and estimated annual percentage changes (EAPCs) were estimated by using Poisson regression. During the study period, 4156 cases of first-ever hospitalization for stroke/TIA were identified. The age-standardized incidence rates of hospitalizations for stroke increased significantly (EAPC 1.83% [95% CI 1.11-2.55%]) from 11.97/100 000 person-years (PY) in 1994 to 16.77/100 000 PY in 2012. TIA hospitalizations increased from 1.93/100 000 PY in 1994 to 5.81/100 000 PY in 2012 and after 2006 more markedly in men than in women (EAPC 16.61% [95% CI 10.45-23.12%]). The incidence of hospitalizations for ischemic stroke was markedly lower among men, but increased significantly from 2006 (EAPC 14.60% [95% CI 6.22-23.63%]). The incidences of hospitalizations for intracerebral hemorrhage and subarachnoid hemorrhage remained stable during the study period. The incidence rates of first-time hospitalizations for ischemic stroke and TIA in young Danish adults have increased substantially since the mid 1990s. The increase was particularly prominent in the most recent years. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  7. Risk of breast cancer following fertility treatment--a registry based cohort study of parous women in Norway.

    Science.gov (United States)

    Reigstad, Marte Myhre; Larsen, Inger Kristin; Myklebust, Tor Åge; Robsahm, Trude Eid; Oldereid, Nan Birgitte; Omland, Anne Katerine; Vangen, Siri; Brinton, Louise Annette; Storeng, Ritsa

    2015-03-01

    Despite increasing numbers of women availing themselves of assisted reproductive technology (ART), effects on cancer risk remain unresolved. Given hormonal exposures, breast cancer risk is of particular concern. The aim of this study is to investigate breast cancer risk amongst women giving birth following ART as compared to that amongst women who gave birth without ART. Data on all women who gave birth in Norway with or without ART, between 1984 and 2010 were obtained from the Medical Birth Registry of Norway (MBRN). 808,834 women eligible for study were linked to the Cancer Registry of Norway. Cox proportional models computed hazard ratios (HR) and 95% confidence intervals (CI) of breast cancer between the two groups, adjusting for age, parity, age at first birth, calendar period and region of residence. In total, 8,037 women were diagnosed with breast cancer during the study period, 138 ART women and 7,899 unexposed. Total follow-up time was 12,401,121 person-years (median 16.0); median age at entry was 32.5 years (range 18.6-49.9) for ART women and 26.3 (range 10.5-54.6) for unexposed. Women exposed to ART had an elevated risk of breast cancer (adjusted HR 1.20, 95% CI 1.01-1.42). Subgroup analyses gave an HR of 1.30 (95% CI 1.07-1.57) for women treated with IVF and 1.35 (95 % CI 1.07-1.71) for women with follow-up >10 years, compared with controls. Our findings of increased risk in the study population warrant continued monitoring of women treated with ART as this population advances into more typical cancer age ranges. © 2014 UICC.

  8. Suicide death and hospital-treated suicidal behaviour in asylum seekers in the Netherlands: a national registry-based study

    Directory of Open Access Journals (Sweden)

    van Oostrum Irene EA

    2011-06-01

    Full Text Available Abstract Background Several suicide and suicidal behaviour risk factors are highly prevalent in asylum seekers, but there is little insight into the suicide death rate and the suicidal behaviour incidence in this population. The main objective of this study is to assess the burden of suicide and hospital-treated non-fatal suicidal behaviour in asylum seekers in the Netherlands and to identify factors that could guide prevention. Methods We obtained data on cases of suicide and suicidal behaviour from all asylum seeker reception centres in the Netherlands (period 2002-2007, age 15+. The suicide death rates in this population and in subgroups by sex, age and region of origin were compared with the rate in the Dutch population; the rates of hospital-treated suicidal behaviour were compared with that in the population of The Hague using indirect age group standardization. Results The study included 35 suicide deaths and 290 cases of hospital-treated suicidal behaviour. The suicide death rate and the incidence of hospital-treated suicidal behaviour differed between subgroups by sex and region of origin. For male asylum seekers, the suicide death rate was higher than that of the Dutch population (N = 32; RR = 2.0, 95%CI 1.37-2.83. No difference was found between suicide mortality in female asylum seekers and in the female general population of the Netherlands (N = 3; RR = 0.73; 95%CI 0.15-2.07. The incidence of hospital-treated suicidal behaviour was high in comparison with the population of The Hague for males and females from Europe and the Middle East/South West Asia, and low for males and females from Africa. Health professionals knew about mental health problems prior to the suicidal behaviour for 80% of the hospital-treated suicidal behaviour cases in asylum seekers. Conclusions In this study the suicide death rate was higher in male asylum seekers than in males in the reference population. The incidence of hospital-treated suicidal behaviour

  9. Educational attainment and differences in relative survival after acute myocardial infarction in Norway: a registry-based population study.

    Science.gov (United States)

    Klitkou, Søren Toksvig; Wangen, Knut R

    2017-08-28

    Although there is a broad societal interest in socioeconomic differences in survival after an acute myocardial infarction, only a few studies have investigated how such differences relate to the survival in general population groups. We aimed to investigate education-specific survival after acute myocardial infarction and to compare this with the survival of corresponding groups in the general population. Our study included the entire population of Norwegian patients admitted to hospitals for acute myocardial infarction during 2008-2010, with a 6- year follow-up period. Patient survival was measured relative to the expected survival in the general population for three educational groups: primary, secondary and tertiary. Education, sex, age and calendar year-specific expected survival were obtained from population life tables and adjusted for the presence of infarction-related mortality. Six-year patient survivals were 56.3% (55.3-57.2) and 65.5% (65.6-69.3) for the primary and tertiary educational groups (95% CIs), respectively. Also 6-year relative survival was markedly lower for the primary educational group: 70.2% (68.6-71.8) versus 81.2% (77.4-84.4). Throughout the follow-up period, patient survival tended to remain lower than the survival in the general population with the same educational background. Both patient survival and relative survival after acute myocardial infarction are positively associated with educational level. Our findings may suggest that secondary prevention has been more effective for the highly educated. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  10. Survival after out-of-hospital cardiac arrest in relation to sex: a nationwide registry-based study.

    Science.gov (United States)

    Wissenberg, Mads; Hansen, Carolina Malta; Folke, Fredrik; Lippert, Freddy K; Weeke, Peter; Karlsson, Lena; Rajan, Shahzleen; Søndergaard, Kathrine Bach; Kragholm, Kristian; Christensen, Erika Frischknecht; Nielsen, Søren L; Køber, Lars; Gislason, Gunnar H; Torp-Pedersen, Christian

    2014-09-01

    Crude survival has increased following an out-of-hospital cardiac arrest (OHCA). We aimed to study sex-related differences in patient characteristics and survival during a 10-year study period. Patients≥12 years old with OHCA of a presumed cardiac cause, and in whom resuscitation was attempted, were identified through the Danish Cardiac Arrest Registry 2001-2010. A total of 19,372 patients were included. One-third were female, with a median age of 75 years (IQR 65-83). Compared to females, males were five years younger; and less likely to have severe comorbidities, e.g., chronic obstructive pulmonary disease (12.8% vs. 16.5%); but more likely to have arrest outside of the home (29.4% vs. 18.7%), receive bystander CPR (32.9% vs. 25.9%), and have a shockable rhythm (32.6% vs. 17.2%), all p<0.001. Thirty-day crude survival increased in males (3.0% in 2001 to 12.9% in 2010); and in females (4.8% in 2001 to 6.7% in 2010), p<0.001. Multivariable logistic regression analyses adjusted for patient characteristics including comorbidities, showed no survival difference between sexes in patients with a non-shockable rhythm (OR 1.00; CI 0.72-1.40), while female sex was positively associated with survival in patients with a shockable rhythm (OR 1.31; CI 1.07-1.59). Analyses were rhythm-stratified due to interaction between sex and heart rhythm; there was no interaction between sex and calendar-year. Temporal increase in crude survival was more marked in males due to poorer prognostic characteristics in females with a lower proportion of shockable rhythm. In an adjusted model, female sex was positively associated with survival in patients with a shockable rhythm. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  11. Causes of perinatal death at a tertiary care hospital in Northern Tanzania 2000–2010: a registry based study

    Directory of Open Access Journals (Sweden)

    Mmbaga Blandina T

    2012-12-01

    Full Text Available Abstract Background Perinatal mortality reflects maternal health as well as antenatal, intrapartum and newborn care, and is an important health indicator. This study aimed at classifying causes of perinatal death in order to identify categories of potentially preventable deaths. Methods We studied a total of 1958 stillbirths and early neonatal deaths above 500 g between July 2000 and October 2010 registered in the Medical Birth Registry and neonatal registry at Kilimanjaro Christian Medical Centre (KCMC in Northern Tanzania. The deaths were classified according to the Neonatal and Intrauterine deaths Classification according to Etiology (NICE. Results Overall perinatal mortality was 57.7/1000 (1958 out of 33 929, of which 1219 (35.9/1000 were stillbirths and 739 (21.8/1000 were early neonatal deaths. Major causes of perinatal mortality were unexplained asphyxia (n=425, 12.5/1000, obstetric complications (n=303, 8.9/1000, maternal disease (n=287, 8.5/1000, unexplained antepartum stillbirths after 37 weeks of gestation (n= 219, 6.5/1000, and unexplained antepartum stillbirths before 37 weeks of gestation (n=184, 5.4/1000. Obstructed/prolonged labour was the leading condition (251/303, 82.8% among the obstetric complications. Preeclampsia/eclampsia was the leading cause (253/287, 88.2% among the maternal conditions. When we excluded women who were referred for delivery at KCMC due to medical reasons (19.1% of all births and 36.0% of all deaths, perinatal mortality was reduced to 45.6/1000. This reduction was mainly due to fewer deaths from obstetric complications (from 8.9 to 2.1/1000 and maternal conditions (from 8.5 to 5.5/1000. Conclusion The distribution of causes of death in this population suggests a great potential for prevention. Early identification of mothers at risk of pregnancy complications through antenatal care screening, teaching pregnant women to recognize signs of pregnancy complications, timely access to obstetric care

  12. Divorce and subsequent increase in uptake of antidepressant medication: a Finnish registry-based study on couple versus individual effects.

    Science.gov (United States)

    Monden, Christiaan W S; Metsä-Simola, Niina; Saarioja, Saska; Martikainen, Pekka

    2015-02-19

    There is an average negative mental health effect for individuals who experience divorce. Little is known whether the pattern of such divorce effects varies within couples. We study whether the husband and wife experience similar harmful effects of divorce, whether they experience opposite effects, or whether divorce effects are purely individual. We use Finnish registry data to compare changes over a period of 5 years in antidepressant use of husbands and wives from 4,558 divorcing couples to 108,637 continuously married pairs aged 40-64, all of whom were healthy at baseline. In the period three years before and after divorce antidepressant use increases substantially. However, the likelihood of uptake of antidepressant medication during this process of divorce by one partner appears to be independent of medication uptake in the other partner. In contrast, among continuously married couples there is a clear pattern of convergence: If one partner starts to use antidepressants this increases the likelihood of uptake of antidepressant medication in the other partner. Our findings suggest that divorce effects on antidepressant use are individual and show no pattern of either convergence or divergence at the level of the couple. The increased incidence of antidepressant use associated with divorce occurs in individuals independent of what happens to their ex-partner.

  13. Predictors of nonfunctional arteriovenous access at hemodialysis initiation and timing of access creation: A registry-based study.

    Directory of Open Access Journals (Sweden)

    Natalia Alencar de Pinho

    Full Text Available Determinants of nonfunctional arteriovenous (AV access, including timing of AV access creation, have not been sufficiently described. We studied 29 945 patients who had predialysis AV access placement and were included in the French REIN registry from 2005 through 2013. AV access was considered nonfunctional when dialysis began with a catheter. We estimated crude and adjusted odds ratio (OR with 95% confidence intervals (CI of nonfunctional versus functional AV access associated with case-mix, facility characteristics, and timing of AV access creation. Analyses were stratified by dialysis start condition (planned or as an emergency and comorbidity profile. Overall, 18% patients had nonfunctional AV access at hemodialysis initiation. In the group with planned dialysis start, female gender (OR 1.43, 95% CI 1.32-1.56, diabetes (OR 1.28, 95% CI 1.15-1.44, and a higher number of cardiovascular comorbidities (OR 1.27, 95% CI 1.09-1.49, and 1.31, 1.05-1.64, for 3 and >3 cardiovascular comorbidities versus none, respectively were independent predictors of nonfunctional AV access. A higher percentage of AV access creation at the region level was associated with a lower rate of nonfunctional AV access (OR 0.98, 95% CI 0.98-0.99 per 1% increase. The odds of nonfunctional AV access decreased as time from creation to hemodialysis initiation increased up to 3 months in nondiabetic patients with fewer than 2 cardiovascular comorbidities and 6 months in patients with diabetes or 2 or more such comorbidities. In conclusion, both patient characteristics and clinical practices may play a role in successful AV access use at hemodialysis initiation. Adjusting the timing of AV access creation to patients' comorbidity profiles may improve functional AV access rates.

  14. Hand eczema, atopic dermatitis and filaggrin mutations in adult Danes: a registry-based study assessing risk of disability pension.

    Science.gov (United States)

    Heede, Nina G; Thuesen, Betina H; Thyssen, Jacob P; Linneberg, Allan; Szecsi, Pal B; Stender, Steen; Menné, Torkil; Johansen, Jeanne D

    2017-08-01

    Atopic dermatitis and hand eczema often impair the ability of people to work. Only a few studies have investigated whether individuals with loss-of-function filaggrin gene (FLG) mutations, who often have severe and early onset of dermatitis, experience occupational consequences. To investigate the personal consequences of having atopic dermatitis and/or hand eczema and FLG mutations. Adult Danes from the general population (n = 3247) and patients with atopic dermatitis and/or hand eczema (n = 496) were genotyped for common FLG mutations, and completed a questionnaire about skin symptoms and hand eczema. Socioeconomic variables, including disability pension, and information on work in risk occupations were retrieved from national registries. The reasons for granting disability pension were unknown. Disability pension was associated with hand eczema in the general population, especially among individuals with a history of atopic dermatitis. Moreover, self-reported hand eczema and atopic dermatitis were associated with particularly high risk of disability pension among FLG mutation carriers [odds ratio (OR) 4.02 and 95% confidence interval (CI): 1.15-14.11; and OR 6.01 and 95%CI: 2.37-15.34, respectively]. Furthermore, 60% of the FLG mutation carriers with atopic dermatitis who developed hand eczema had experienced symptoms before adulthood. In the general population, self-reported hand eczema and atopic dermatitis, particularly in individuals with a genetically impaired skin barrier, were associated with disability pension, suggesting that FLG mutations carriers with a history of atopic dermatitis and hand eczema could benefit from early attention with respect to choice of occupation. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Effect of co-twin gender on neurodevelopmental symptoms: a twin register study.

    Science.gov (United States)

    Eriksson, Jonna Maria; Lundström, Sebastian; Lichtenstein, Paul; Bejerot, Susanne; Eriksson, Elias

    2016-01-01

    Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are neurodevelopmental disorders thought to have both genetic and environmental causes. It has been hypothesized that exposure to elevated levels of prenatal testosterone is associated with elevated traits of ASD and ADHD. Assuming that testosterone levels from a dizygotic male twin fetus may lead to enhanced testosterone exposure of its co-twins, we aimed to test the prenatal testosterone hypothesis by comparing same-sex with opposite-sex dizygotic twins with respect to neurodevelopmental symptoms. Neuropsychiatric traits were assessed in a population-based twin cohort from the Child and Adolescent Twin Study in Sweden (CATSS). Parental interviews were conducted for 16,312 dizygotic twins, 9 and 12 years old, with the Autism-Tics, ADHD, and other Comorbidities inventory (A-TAC). Girls with a female co-twin had an increased risk of reaching the cut-off score for ADHD compared with girls with a male co-twin. Both boys and girls with a female co-twin displayed a larger number of traits related to attention deficit and repetitive and stereotyped behaviors than those with a male twin. In girls, this also extended to social interaction and the combined measures for ASD and ADHD, however, with small effect sizes. Our results are reverse to what would have been expected from the prenatal testosterone hypothesis but consistent with a previous study of ASD and ADHD traits in dizygotic twins. The seemingly protective effect for girls of having a twin brother may be an effect of parent report bias, but may also be an unexpected effect of sharing the intrauterine environment with a male co-twin.

  16. Characterisation of antibiotic prescriptions for acute respiratory tract infections in Danish general practice: a retrospective registry based cohort study.

    Science.gov (United States)

    Aabenhus, Rune; Hansen, Malene Plejdrup; Saust, Laura Trolle; Bjerrum, Lars

    2017-05-19

    Inappropriate use of antibiotics is contributing to the increasing rates of antimicrobial resistance. Several Danish guidelines on antibiotic prescribing for acute respiratory tract infections in general practice have been issued to promote rational prescribing of antibiotics, however it is unclear if these recommendations are followed. We aimed to characterise the pattern of antibiotic prescriptions for patients diagnosed with acute respiratory tract infections, by means of electronic prescriptions, labeled with clinical indications, from Danish general practice. Acute respiratory tract infections accounted for 456,532 antibiotic prescriptions issued between July 2012 and June 2013. Pneumonia was the most common indication with 178,354 prescriptions (39%), followed by acute tonsillitis (21%) and acute otitis media (19%). In total, penicillin V accounted for 58% of all prescriptions, followed by macrolides (18%) and amoxicillin (15%). The use of second-line agents increased with age for all indications, and comprised more than 40% of the prescriptions in patients aged >75 years. Women were more often prescribed antibiotics regardless of clinical indication. This is the first Danish study to characterise antibiotic prescription patterns for acute respiratory tract infections by data linkage of clinical indications. The findings confirm that penicillin V is the most commonly prescribed antibiotic agent for treatment of patients with an acute respiratory tract infection in Danish general practice. However, second-line agents like macrolides and amoxicillin with or without clavulanic acid are overused. Strategies to improve the quality of antibiotic prescribing especially for pneumonia, acute otitis media and acute rhinosinusitis are warranted. TRACKING THE OVERUSE OF ANTIBIOTICS: Better adherence to guidelines for prescribing antibiotics for different respiratory tract infections are warranted in Danish general practice. The over-use of antibiotics, particularly so

  17. Familial aggregation of atrial fibrillation: a study in Danish twins

    DEFF Research Database (Denmark)

    Christophersen, Ingrid Elisabeth; Ravn, Lasse Steen; Budtz-Joergensen, Esben

    2009-01-01

    BACKGROUND: Heritability may play a role in nonfamilial atrial fibrillation (AF). We hypothesized that a monozygotic (MZ) twin whose co-twin was diagnosed with AF would have an increased risk of the disease compared with a dizygotic (DZ) twin in the same situation. METHODS AND RESULTS: A sample......-free survival times, we compared the time span between occurrences of disease in MZ and DZ twins. The unaffected twin was included when his or her twin-sibling (the index twin) was diagnosed with AF. After adjustment for age at entry, MZ twins had a significantly shorter event-free survival time (hazard ratio......, 2.0; 95% CI, 1.3 to 3.0), thereby indicating a genetic component. Using biometric models, we estimated the heritability of AF to be 62% (55% to 68%), due to additive genetics. There were no significant differences across sexes. CONCLUSIONS: All the analyses of twin similarities in the present study...

  18. Registry-based randomized controlled trials merged the strength of randomized controlled trails and observational studies and give rise to more pragmatic trials.

    Science.gov (United States)

    Mathes, Tim; Buehn, Stefanie; Prengel, Peggy; Pieper, Dawid

    2018-01-01

    The objective of this study was to analyze the features of registry-based randomized trials (rRCTs). We systematically searched PubMed for rRCTs. Study selection was performed independently by two reviewers. We extracted all data in standardized tables and prepared descriptive summary statistics. The search resulted in 1,202 hits. We included 71 rRCTs. Most rRCTs were from Denmark and Sweden. Chronic conditions were considered in 82.2%. A preventive intervention was examined in 45.1%. The median of included patients was 2,000 (range: 69-246,079). Definition of the study population was mostly broad. Study procedures were regularly little standardized. The number of included and analyzed patients was the same in 82.1%. In half of the rRCTs, more than one registry was utilized. Various linkage techniques were used. In median, two outcomes were collected from the registry/ies. The median follow-up of the rRCTs was 5.3 years (range: 6 weeks to 27 years). Information on quality of registry data was reported in 11.3%. rRCTs can provide valid (randomization, low lost-to-follow-up rates, generalizable) patient important long-term comparative-effectiveness data for relative little effort. Researchers planning an RCT should always check whether existing registries can be used for data collection. Reporting on data quality must be improved for use in evidence synthesis. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Relationship between refractive error and ocular biometrics in twin children: the Guangzhou Twin Eye Study.

    Science.gov (United States)

    Wang, Decai; Liu, Bin; Huang, Shengsong; Huang, Wenyong; He, Mingguang

    2014-09-01

    A cross-sectional study was conducted to explore the relationship between refractive error and ocular biometrics in children from the Guangzhou twin eye study. Twin participants aged 7-15 years were selected from Guangzhou Twin Eye Study. Ocular examinations included visual acuity measurement, ocular motility evaluation, autorefraction under cycloplegia, and anterior segment, media, and fundus examination. Axial length (AL), anterior chamber depth (ACD), and corneal curvature radius were measured using partial coherence laser interferometry. A multivariate linear regression model was used for statistical analysis. Twin children from Guangzhou city showed a decreased spherical equivalent with age, whereas both AL and ACD were increased and corneal curvature radius remained unchanged. When adjusted by age and gender, the data from 77% of twins presenting with spherical equivalent changes indicated that these were caused by predictable variables (R2 = 0.77, P biometrics. Refractive status is largely determined by axial length as the major factor.

  20. Timing of oral anticoagulant therapy in acute ischemic stroke with atrial fibrillation: study protocol for a registry-based randomised controlled trial.

    Science.gov (United States)

    Åsberg, Signild; Hijazi, Ziad; Norrving, Bo; Terént, Andreas; Öhagen, Patrik; Oldgren, Jonas

    2017-12-02

    Oral anticoagulation therapy is recommended for the prevention of recurrent ischemic stroke in patients with atrial fibrillation (AF). Current guidelines do not provide evidence-based recommendations on optimal time-point to start anticoagulation therapy after an acute ischemic stroke. Non-vitamin K antagonist oral anticoagulants (NOACs) may offer advantages compared to warfarin because of faster and more predictable onset of action and potentially a lower risk of intracerebral haemorrhage also in the acute phase after an ischemic stroke. The TIMING study aims to establish the efficacy and safety of early vs delayed initiation of NOACs in patients with acute ischemic stroke and AF. The TIMING study is a national, investigator-led, registry-based, multicentre, open-label, randomised controlled study. The Swedish Stroke Register is used for enrolment, randomisation and follow-up of 3000 patients, who are randomised (1:1) within 72 h from ischemic stroke onset to either early (≤ 4 days) or delayed (≥ 5-10 days) start of NOAC therapy. The primary outcome is the composite of recurrent ischemic stroke, symptomatic intracerebral haemorrhage, or all-cause mortality within 90 days after randomisation. Secondary outcomes include: individual components of the primary outcome at 90 and 365 days; major haemorrhagic events; functional outcome by the modified Rankin Scale at 90 days; and health economics. In an optional biomarker sub-study, blood samples will be collected after randomisation from approximately half of the patients for central analysis of cardiovascular biomarkers after study completion. The study is funded by the Swedish Medical Research Council. Enrolment of patients started in April 2017. The TIMING study addresses the ongoing clinical dilemma of when to start NOAC after an acute ischemic stroke in patients with AF. By the inclusion of a randomisation module within the Swedish Stroke Register, the advantages of a prospective randomised study design

  1. The 16th International Twin Congress: Highlights from Madrid/Twin Research: Twin Study of Partner Aggression; ABO Incompatibility in Dizygotic Twins; Growth Discordance in a Monoamniotic Twin Pair; Quick Note on Twin Implantation/In the Media: Long-Lost Twins Found; NASA Twin Experiment; Twin Brothers and the Las Vegas Attack; Retired Twin Airline Pilots; Twin Film Clips.

    Science.gov (United States)

    Segal, Nancy L

    2018-02-01

    Highlights from the 16th International Twin Congress, held in Madrid, Spain from November 16-18, 2017, are presented. The Twin Congress, formerly held every three years, now takes place biennially with a single-day meeting organized during the off years. This meeting is the largest gathering of scientific twin researchers, medical personnel, and representatives of multiple birth organizations in the world. This overview is followed by reviews of recent twin research and commentary concerning partner aggression, ABO incompatibility in dizygotic twins, growth discordance in a monoamniotic twin pair and twin implantation. The article closes with summaries of timely topics in the media, namely a father's finding of his long-lost twin children, early results from the NASA twin experiment, twin brothers at the center of the October 2017 Las Vegas attack, retired twin airline pilots, and clips from recent films with twin-based themes.

  2. Pre-Vaccination Care-Seeking in Females Reporting Severe Adverse Reactions to HPV Vaccine. A Registry Based Case-Control Study.

    Directory of Open Access Journals (Sweden)

    Kåre Mølbak

    Full Text Available Since 2013 the number of suspected adverse reactions to the quadrivalent human papillomavirus (HPV vaccine reported to the Danish Medicines Agency (DMA has increased. Due to the resulting public concerns about vaccine safety, the coverage of HPV vaccinations in the childhood vaccination programme has declined. The aim of the present study was to determine health care-seeking prior to the first HPV vaccination among females who suspected adverse reactions to HPV vaccine.In this registry-based case-control study, we included as cases vaccinated females with reports to the DMA of suspected severe adverse reactions. We selected controls without reports of adverse reactions from the Danish vaccination registry and matched by year of vaccination, age of vaccination, and municipality, and obtained from the Danish National Patient Registry and The National Health Insurance Service Register the history of health care usage two years prior to the first vaccine. We analysed the data by logistic regression while adjusting for the matching variables.The study included 316 cases who received first HPV vaccine between 2006 and 2014. Age range of cases was 11 to 52 years, with a peak at 12 years, corresponding to the recommended age at vaccination, and another peak at 19 to 28 years, corresponding to a catch-up programme targeting young women. Compared with 163,910 controls, cases had increased care-seeking in the two years before receiving the first HPV vaccine. A multivariable model showed higher use of telephone/email consultations (OR 1.9; 95% CI 1.2-3.2, physiotherapy (OR 2.1; 95% CI 1.6-2.8 and psychologist/psychiatrist (OR 1.9; 95% CI 1.3-2.7. Cases were more likely to have a diagnosis in the ICD-10 chapters of diseases of the digestive system (OR 1.6; 95% CI 1.0-2.4, of the musculoskeletal system (OR 1.6; 95% CI 1.1-2.2, symptoms or signs not classified elsewhere (OR 1.8; 95% CI 1.3-2.5 as well as injuries (OR 1.5; 95% CI 1.2-1.9.Before receiving the

  3. Lithium is associated with decrease in all-cause and suicide mortality in high-risk bipolar patients: A nationwide registry-based prospective cohort study.

    Science.gov (United States)

    Toffol, Elena; Hätönen, Taina; Tanskanen, Antti; Lönnqvist, Jouko; Wahlbeck, Kristian; Joffe, Grigori; Tiihonen, Jari; Haukka, Jari; Partonen, Timo

    2015-09-01

    Mortality rates, in particular due to suicide, are especially high in bipolar patients. This nationwide, registry-based study analyses the associations of medication use with hospitalization due to attempted suicides, deaths from suicide, and overall mortality across different psychotropic agents in bipolar patients. Altogether 826 bipolar patients hospitalized in Finland between 1996-2003 because of a suicide attempt were followed-up for a mean of 3.5 years. The relative risk of suicide attempts leading to hospitalization, completed suicide, and overall mortality during lithium vs. no-lithium, antipsychotic vs. no-antipsychotic, valproic acid vs. no-valproic acid, antidepressant vs. no-antidepressant and benzodiazepine vs. no-benzodiazepine treatment was measured. The use of valproic acid (RR=1.53, 95% CI: 1.26-1.85, p<0.001), antidepressants (RR=1.49, 95% CI: 1.23-1.8, p<0.001) and benzodiazepines (RR=1.49, 95% CI: 1.23-1.80, p<0.001) was associated with increased risk of attempted suicide. Lithium was associated with a (non-significantly) lower risk of suicide attempts, and with significantly decreased suicide mortality in univariate (RR=0.39, 95% CI: 0.17-0.93, p=0.03), Cox (HR=0.37, 95% CI: 0.16-0.88, p=0.02) and marginal structural models (HR=0.31, 95% CI: 0.12-0.79, p=0.02). Moreover, lithium was related to decreased all-cause mortality by 49% (marginal structural models). Only high-risk bipolar patients hospitalized after a suicide attempt were studied. Diagnosis was not based on standardized diagnostic interviews; treatment regimens were uncontrolled. Maintenance therapy with lithium, but not with other medications, is linked to decreased suicide and all-cause mortality in high-risk bipolar patients. Lithium should be considered for suicide prevention in high-risk bipolar patients. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. 'Biracial'-Looking Twins: A New Twin Type?/Twin Research: Twins with Cystic Teratomas; Sleep Quality and Body Mass Index; Previable Membrane Rupture/Print and Online Reports: Twins Born to a Sister Surrogate; NASA Twin Study; African-Cosmopolitan Twin Fashion Inspirations; Triplet Hockey Stars.

    Science.gov (United States)

    Segal, Nancy L

    2017-06-01

    Dizygotic (DZ) co-twins born to mothers and fathers from different racial or ethnic backgrounds often resemble one parent much more than the other. As such, these pairs comprise a unique subset of twins for investigating how others' responses to their different looks may affect their personalities and self-esteem. This article describes some of these twin pairs and some challenges of raising them, and suggests ways they may be used in research. Next, recent twin research on cystic teratomas, relations between sleep quality and body mass index, and previable membrane rupture is described. The final section concerns twins, twin studies, and related events in the media, namely: twins born to a sister surrogate, the NASA twin investigation, inspiring African-Cosmopolitan twins in fashion, and triplet Hockey Stars.

  5. Highlights from the 15th International Congress of Twin Studies/Twin Research: Differentiating MZ Co-twins Via SNPs; Mistaken Infant Twin-Singleton Hospital Registration; Narcolepsy With Cataplexy; Hearing Loss and Language Learning/Media Mentions: Broadway Musical Recalls Conjoined Hilton Twins; High Fashion Pair; Twins Turn 102; Insights From a Conjoined Twin Survivor.

    Science.gov (United States)

    Segal, Nancy L

    2015-02-01

    Highlights from the 15th International Congress of Twin Studies are presented. The congress was held November 16-19, 2014 in Budapest, Hungary. This report is followed by summaries of research addressing the differentiation of MZ co-twins by single nucleotide polymorphisms (SNPs), an unusual error in infant twin-singleton hospital registration, twins with childhood-onset narcolepsy with cataplexy, and the parenting effects of hearing loss in one co-twin. Media interest in twins covers a new Broadway musical based on the conjoined twins Violet and Daisy Hilton, male twins becoming famous in fashion, twins who turned 102 and unique insights from a conjoined twin survivor. This article is dedicated to the memory of Elizabeth (Liz) Hamel, DZA twin who met her co-twin for the first time at age seventy-eight years. Liz and her co-twin, Ann Hunt, are listed in the 2015 Guinness Book of Records as the longest separated twins in the world.

  6. A registry-based follow-up study, comparing the incidence of cardiovascular disease in native Danes and immigrants born in Turkey, Pakistan and the former Yugoslavia: do social inequalities play a role?

    DEFF Research Database (Denmark)

    Hempler, Nana F; Larsen, Finn; Nielsen, Signe S

    2011-01-01

    ), such as employment, income and housing conditions influenced potential differences. METHODS: In this registry-based follow-up study individuals were identified in a large database that included individuals from two major regions in Denmark, corresponding to about 60% of the Danish population. Incident cases of CVD......, differences in CVD and AMI were reduced after adjustment for SES, in particular, among Turks regarding CVD. In women, effects were particularly reduced among Yugoslavians in the case of CVD and in Turks in the case of CVD and AMI after adjustment for SES. CONCLUSIONS: In conclusion, country of birth...

  7. Genetic influences on dietary variety - Results from a twin study

    NARCIS (Netherlands)

    Scheibehenne, Benjamin; Todd, Peter M.; van den Berg, Stéphanie Martine; Hatemi, Peter K.; Eaves, Lindon J.; Vogler, Christian

    2014-01-01

    The heritability of variety seeking in the food domain was estimated from a large sample (N = 5,543) of middle age to elderly monozygotic and dizygotic twins from the “Virginia 30,000” twin study. Different dietary variety scores were calculated based on a semi-quantitative food choice questionnaire

  8. A twin-case study of developmental number sense impairment

    NARCIS (Netherlands)

    Davidse, Neeltje J.; de Jong, Maria T.; Shaul, Shelley; Bus, Adriana G

    2014-01-01

    The current study reports on 9-year-old monozygotic twin girls who fail to make any progress in learning basic mathematics in primary education. We tested the hypothesis that the twins' core maths problems were deficits in number sense that manifested as impairments in approximate and small number

  9. Disease-Concordant Twins Empower Genetic Association Studies

    DEFF Research Database (Denmark)

    Tan, Qihua; Li, Weilong; Vandin, Fabio

    2017-01-01

    and ordinary healthy samples as controls. We examined the power gain of the twin-based design for various scenarios (i.e., cases from monozygotic and dizygotic twin pairs concordant for a disease) and compared the power with the ordinary case-control design with cases collected from the unrelated patient...... concordant for a disease, should confer increased power in genetic association analysis because of their genetic relatedness. We conducted a computer simulation study to explore the power advantage of the disease-concordant twin design, which uses singletons from disease-concordant twin pairs as cases...... population. Simulation was done by assigning various allele frequencies and allelic relative risks for different mode of genetic inheritance. In general, for achieving a power estimate of 80%, the sample sizes needed for dizygotic and monozygotic twin cases were one half and one fourth of the sample size...

  10. Family and twin studies on methacholine hypersensitivity

    Directory of Open Access Journals (Sweden)

    Robert G Townley

    1998-01-01

    Full Text Available Essentially all asthmatics demonstrate a marked sensitivity to inhaled methacholine and histamine, termed non-specific bronchial (airway hyperresponsiveness (BHR. Airway hyperresponsiveness is a characteristic not only of asthmatics, but can be found in many persons with allergic rhinitis as well as in members of asthmatics' families. The presence of BHR usually precedes the development of clinically identifiable asthma. In recent years there has been an emphasis on inflammation, inducing hyperresponsiveness. However, these factors increase airway hyperresponsiveness by a magnitude of only three-fold compared with normal subjects. The important question is not why asthmatics respond, but why normal subjects do not. The normal subjects are quite able to maintain normal airway function in the presence of high concentrations of methacholine or histamine in vivo but not in vitro, suggesting the presence of protective mechanisms in vivo that are either lacking in, or are less effective in, the asthmatic subjects. There is a strong correlation between the degree of airway hyperresponsiveness and the severity of asthma. In order to determine whether methacholine sensitivity could be used as a potential genetic marker, we studied 750 subjects from 53 asthma families and 26 control families. The best sensitivity and specificity is at 200 breath units. Only 6% of the allergic rhinitis subjects showed a high positive response, but 30% overlapped with asthmatics in that they reacted with 200 breath units or less. There was a group of non-atopic subjects from asthma families who responded by 200 breath units, but there was a significantly lower percentage from normal families. Being from an asthma family is a risk factor in terms of subsequent development of asthma and increased airway reactivity. The parent data suggest that airway reactivity is transmitted to succeeding generations. Studies of twins have revealed that the concordance of asthma is higher in

  11. The Child and Adolescent Twin Study in Sweden (CATSS).

    Science.gov (United States)

    Anckarsäter, Henrik; Lundström, Sebastian; Kollberg, Linnea; Kerekes, Nora; Palm, Camilla; Carlström, Eva; Långström, Niklas; Magnusson, Patrik K E; Halldner, Linda; Bölte, Sven; Gillberg, Christopher; Gumpert, Clara; Råstam, Maria; Lichtenstein, Paul

    2011-12-01

    The Child and Adolescent Twin Study in Sweden (CATSS) is an ongoing longitudinal twin study targeting all twins born in Sweden since July 1, 1992. Since 2004, parents of twins are interviewed regarding the children's somatic and mental health and social environment in connection with their 9th or 12th birthdays (CATSS-9/12). By January 2010, 8,610 parental interviews concerning 17,220 twins had been completed, with an overall response rate of 80%. At age 15 (CATSS-15) and 18 (CATSS-18), twins and parents complete questionnaires that, in addition to assessments of somatic and mental health, include measures of personality development and psychosocial adaptation. Twin pairs in CATSS-9/12 with one or both twins screening positive for autism spectrum disorders, attention deficit/hyperactivity disorder, tic disorders, developmental coordination disorder, learning disorders, oppositional defiant disorder, conduct disorder, obsessive-compulsive disorder, and/or eating problems have been followed with in-depth questionnaires on family, social environment and personality, and subsequently by clinical assessments at age 15 together with randomly selected population controls, including 195 clinically assessed twin pairs from the first 2 year cohorts (CATSS-15/DOGSS). This article describes the cohorts and study groups, data collection, and measures used. Prevalences, distributions, heritability estimates, ages at onset, and sex differences of mental health problems in the CATSS-9/12, that were analyzed and found to be overall comparable to those of other clinical and epidemiological studies. The CATSS study has the potential of answering important questions on the etiology of childhood mental health problems and their role in the development of later adjustment problems.

  12. Genetic Influences on Pulmonary Function: A Large Sample Twin Study

    DEFF Research Database (Denmark)

    Ingebrigtsen, Truls S; Thomsen, Simon F; van der Sluis, Sophie

    2011-01-01

    Heritability of forced expiratory volume in one second (FEV(1)), forced vital capacity (FVC), and peak expiratory flow (PEF) has not been previously addressed in large twin studies. We evaluated the genetic contribution to individual differences observed in FEV(1), FVC, and PEF using data from...... the largest population-based twin study on spirometry. Specially trained lay interviewers with previous experience in spirometric measurements tested 4,314 Danish twins (individuals), 46-68 years of age, in their homes using a hand-held spirometer, and their flow-volume curves were evaluated. Modern variance...

  13. Reared-Apart Chinese Twins: Chance Discovery/Twin-Based Research: Twin Study of Media Use; Twin Relations Over the Life Span; Breast-Feeding Opposite-Sex Twins/Print and Online Media: Twins in Fashion; Second Twin Pair Born to Tennis Star; Twin Primes; Twin Pandas.

    Science.gov (United States)

    Segal, Nancy L

    2017-04-01

    A January 2017 reunion of 10-year-old reared-apart Chinese twin girls was captured live on ABC's morning talk show Good Morning America, and rebroadcast on their evening news program Nightline. The twins' similarities and differences, and their participation in ongoing research will be described. This story is followed by reviews of twin research concerning genetic and environmental influences on media use, twin relations across the lifespan and the breast-feeding of opposite-sex twins. Popular interest items include twins in fashion, the second twin pair born to an internationally renowned tennis star, twin primes and twin pandas.

  14. A phenomenological study on twin screw extruders

    NARCIS (Netherlands)

    Janssen, L.P.B.M.

    1976-01-01

    Although more and more twin screw extruders are being used in the polymer industry, the theoretical background is relatively undeveloped. The literature abounds in contradictions and often informs the reader that all extrusion problems can be solved if a certain new design is considered. The

  15. A Possible Twin: The 1960s Twin Study Revisited/Twin Research: Twin-to-Twin Heart Transplantation; Distinguishing Monozygotic Twins; Twin Conceptions via Oocyte Donation; Factors Affecting Craniofacial Traits/In the Media: Triplet Delivery in the UK; Conjoined Twins and the Concept of Self; Colombian Twin Trainers; Skin Grafting to Save an Identical Co-Twin; Lack of Physical Flaws in Dolly the Cloned Sheep; Possible Conjoined Twins of Opposite-Sex; Passing of the Remaining Twin From the World's Longest Separated Pair.

    Science.gov (United States)

    Segal, Nancy L

    2018-04-01

    This article begins with the story of a 51-year-old Los Angeles, California man, Justin Goldberg, whose daughter caught a glimpse of his striking look-alike at a popular market. Many people have so-called doppelgängers, but this occurrence is especially intriguing - the individual in question, born in New York City in the mid-1960s to an unwed mother, was an adoptee placed by the Louise Wise Adoption Agency. This agency, under the guidance of a prominent psychiatrist, decided to place twins in separate homes. Some of these twin children were part of a controversial child development study that was hidden from them and their parents. Next, recent and current twin research on heart transplantation, distinguishing monozygotic co-twins, twin conceptions via oocyte donation and factors affecting craniofacial traits are summarized. The article concludes with highlights on twins in the media, specifically, a triplet delivery in the United Kingdom, self-concept and consciousness in conjoined twins, Colombian twin trainers, skin grafting to save an identical co-twin, lack of physical flaws in Dolly the cloned sheep, possible opposite-sex conjoined twins, and the passing of the remaining twin from the world's longest separated pair.

  16. Neurological impairment in a surviving twin following intrauterine fetal demise of the co-twin: a case study.

    Science.gov (United States)

    Forrester, K R; Keegan, K M; Schmidt, J W

    2013-01-01

    It has been established that twin pregnancies are at an increased risk for complications, including the risk of morbidity or mortality for one or both of the infants. Cerebral palsy and other associated neurological deficits also occur at higher rates in twin pregnancies. This report examines two cases of intrauterine demise of one twin with subsequent survival of the co-twin. In both cases, the surviving infant suffered significant neurological sequelae. Impairments observed in these two cases include multicystic encephalomalacia and periventricular leukomalacia as well as the subsequent development of cerebral palsy. This case study explores the predisposing factors, incidence, pathophysiology, consequences, and future research implications of these findings.

  17. Birth weight, sex, and celiac disease: a nationwide twin study

    Directory of Open Access Journals (Sweden)

    Kuja-Halkola R

    2017-11-01

    =1.11–2.02. However, the association was not significant in within-pair analyses for both dizygotic and monozygotic twins and for both sexes.Conclusion: This population-based study found that in male twins, higher birth weight was associated with higher risk of CD. However, when comparing discordant twin pairs in within-twin pair analyses, there was no statistically significant association between birth weight, intrauterine growth, and future risk of CD. Keywords: autoimmune, gestational age, gluten, registries, risk factors, twins

  18. Personality and birth order in monozygotic twins adopted apart: a test of Sulloway's theory; Research Reviews: twin births and cancer risk in mothers, male sexual dysfunction, twin study of ultimatum game behavior; Human Interest: 'The Land of Twins', twin-like reunion-I, twin-like reunion-II.

    Science.gov (United States)

    Segal, Nancy L

    2008-02-01

    A brief overview of Sulloway's (1996) theory of birth order and personality is presented. A reared apart twin approach for testing his personality findings regarding openness to experience and conscientiousness in first borns and later borns is described. This is followed by summaries of three recent twin studies. The topics include cancer risk in mother of twins, sexual dysfunction in males and responder behavior during ultimatum games. This article concludes with a discussion of twinning rates and rituals among the Yoruba of western Nigeria, and descriptions of two unusual reunions between siblings and twins.

  19. Sleep Duration, Mortality, and Heredity-A Prospective Twin Study.

    Science.gov (United States)

    Åkerstedt, Torbjörn; Narusyte, Jurgita; Alexanderson, Kristina; Svedberg, Pia

    2017-10-01

    A number of studies have shown a U-shaped association between sleep duration and mortality. Since sleep duration is partly genetically determined, it seems likely that its association with mortality is also genetically influenced. The purpose of the present study was to investigate the influence on heredity on the association between sleep duration and mortality. We used a cohort of 14267 twins from the Swedish Twin Registry. A Cox proportional hazards regression analysis, adjusted for a number of covariates, confirmed a clear U shape with a hazard ratio (HR) = 1.34 and 95% confidence interval (CI) = 1.15-1.57 for a sleep duration of ≤6.5 hours and HR = 1.18 (CI = 1.07-1.30) for sleep of ≥9.5 hours. Reference value was 7.0 hours. A co-twin analysis of 1942 twins discordant on mortality showed a HR = 2.66 (CI = 1.17-6.04) for long (≥9.5 hours) sleep in monzygotic twins and an HR = 0.66 (CI = 0.20-2.14) for short (sleep. In dizygotic twins, no association was significant. The heritability for mortality was 28% for the whole group, while it was 86% for short sleepers and 42% for long sleepers. Thus, the link with mortality for long sleep appears to be more due to environmental factors than to heredity, while heritability dominates among short sleepers. We found that both long and short sleep were associated with higher total mortality, that the difference in mortality within twin pairs is associated with long sleep, and that short sleep has a higher heritability for mortality, while long sleep is associated with more environmental influences on mortality. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

  20. Twin Research and the Arts: Interconnections / Twin Research: Twin Studies of Sexual Orientation; A Historical Biological Twin Gem; GWAS Approach to Who Has Twins / Newsworthy: Twins on College Campuses; 'Brainprint': Personal Identification by Brain Waves.

    Science.gov (United States)

    Segal, Nancy L

    2016-08-01

    The interrelatedness between twin research and the arts is explored via a new play about a famous case. In the 1960s, identical twin David Bruce Reimer was accidentally castrated as an infant during circumcision to correct a urinary problem. The decision to raise him as a girl, and the consequences of that decision, are explored in the new theatrical production of Boy. Other examples of the arts mirroring science, and vice versa, are described. Next, brief reviews and summaries of twin research on sexual orientation, 1860s' knowledge of placental arrangements and twinning mechanisms, and genes underlying multiple birth conception and fertility related measures are provided. This article concludes with a look at twins on college campuses and the identification of individuals by their brain waves. A correction and clarification regarding my article on the Brazilian Twin Registry in the last issue of THG (Segal, 2016) is also provided.

  1. Twins for epigenetic studies of human aging and development

    DEFF Research Database (Denmark)

    Tan, Qihua; Christiansen, Lene; Thomassen, Mads

    2013-01-01

    Most of the complex traits including aging phenotypes are caused by the interaction between genome and environmental conditions and the interface of epigenetics may be a central mechanism. Although modern technologies allow us high-throughput profiling of epigenetic patterns already at genome level...... and environmental contributions to human diseases and complex traits. In the era of functional genomics, the valuable sample of twins is helping to bridge the gap between gene activity and the environments through epigenetic mechanisms unlimited by DNA sequence variations. We propose to extend the classical twin...... design to study the aging-related molecular epigenetic phenotypes and link them with environmental exposures especially early life events. Different study designs and application issues will be highlighted and novel approaches introduced with aim at making uses of twins in assessing the environmental...

  2. Occupational risk factors for testicular cancer: a registry-based case-control study in Rhineland Palatinate – Germany [Berufliche Risikofaktoren für Hodenkrebs: eine Register-basierte Fall-Kontroll-Studie in Rheinland-Pfalz – Deutschland

    Directory of Open Access Journals (Sweden)

    Yousif, Lamyaa

    2013-11-01

    Full Text Available [english] Objectives: Testicular cancer affects mainly men below the age of 50. An association with occupation and social status has been suggested but risk factors are not well understood. A registry-based case-control study focusing on occupation was performed in Germany.Methods: All 348 testicular cancer cases with available gainful occupational information registered between 2000 and 2005; as well as uitable controls (from a pool of other cancers were drawn from the Cancer Registry of Rhineland-Palatinate. Unconditional logistic regression was used to compute odds ratios (OR and associated onfidence intervals (CI.Results: Slightly elevated OR were observed for technicians and related professionals (OR 1.62, 95% CI 1.00–2.63 and for clerical support workers (OR 1.71, 95% CI 1.14–2.56. This increase was highest in the age group 20–50 for technicians (OR 2.02, 95% CI 1.23–3.33 and clerks (OR 2.00, 95% CI 1.30–3.09, respectively. An association with testicular cancer was observed for no other occupation.Conclusion: An increased risk of testicular cancer was observed for technicians and related professionals and clerical support workers. This could be related to socioeconomic status or sedentary life style, two factors that were identified in previous studies. While the feasibility of a purely registry-based study was shown, missing occupational data and the choice of cancer controls represent challenges to the validity of this approach.[german] Ziele: Hodenkrebs betrifft vor allem junge Männer im Alter von unter 50 Jahren. Ein Zusammenhang zwischen erhöhtem Auftreten von Hodenkrebs und Beruf bzw. sozialem Status wurde untersucht (in Betracht gezogen, aber die Risikofaktoren sind bislang noch nicht umfassend erforscht. Eine Register-basierte Fall-Kontroll-Studie zur Untersuchung eines Zusammenhangs von beruflicher Erwerbstätigkeit und Hodenkrebs wurde in Deutschland durchgeführt.Methoden: 348 Hodenkrebsfälle mit den verf

  3. Birth order, gestational age, and risk of delivery related perinatal death in twins: retrospective cohort study

    Science.gov (United States)

    Smith, Gordon C S; Pell, Jill P; Dobbie, Richard

    2002-01-01

    Objective To determine whether twins born second are at increased risk of perinatal death because of complications during labour and delivery. Design Retrospective cohort study. Setting Scotland, 1992 and 1997. Participants All twin births at or after 24 weeks' gestation, excluding twin pairs in which either twin died before labour or delivery or died during or after labour and delivery because of congenital abnormality, non-immune hydrops, or twin to twin transfusion syndrome. Main outcome measure Delivery related perinatal deaths (deaths during labour or the neonatal period). Results Overall, delivery related perinatal deaths were recorded for 23 first twins only and 23 second twins only of 1438 twin pairs born before 36 weeks (preterm) by means other than planned caesarean section (P>0.99). No deaths of first twins and nine deaths of second twins (P=0.004) were recorded among the 2436 twin pairs born at or after 36 weeks (term). Discordance between first and second twins differed significantly in preterm and term births (P=0.007). Seven of nine deaths of second twins at term were due to anoxia during the birth (2.9 (95% confidence interval 1.2 to 5.9) per 1000); five of these deaths were associated with mechanical problems with the second delivery following vaginal delivery of the first twin. No deaths were recorded among 454 second twins delivered at term by planned caesarean section. Conclusions Second twins born at term are at higher risk than first twins of death due to complications of delivery. Previous studies may not have shown an increased risk because of inadequate categorisation of deaths, lack of statistical power, inappropriate analyses, and pooling of data about preterm births and term births. What is already known on this topicIt is difficult to assess the wellbeing of second twins during labourDeliveries of second twins are at increased risk of mechanical problems, such as cord prolapse and malpresentation, after vaginal delivery of first twins

  4. Incidence of spontaneous twin anemia-polycythemia sequence in monochorionic-diamniotic twin pregnancies: Single-center prospective study.

    Science.gov (United States)

    Yokouchi, Tae; Murakoshi, Takeshi; Mishima, Takashi; Yano, Hiroko; Ohashi, Madoka; Suzuki, Takashi; Shinno, Takashi; Matsushita, Mitsuru; Nakayama, Satoru; Torii, Yuichi

    2015-06-01

    The purpose of this study was to prospectively estimate the incidence of spontaneous twin anemia-polycythemia sequence (TAPS) in monochorionic-diamniotic twin pregnancies. We prospectively examined umbilical cord hemoglobin (Hb) and reticulocyte count of consecutive monochorionic-diamniotic twin pregnancies delivered at Seirei Hamamatsu General Hospital from December 2006 to September 2013. We excluded cases of twin-twin transfusion syndrome, intrauterine fetal demise, and missing data (Hb and reticulocyte count missing from the medical record). TAPS was diagnosed using the postnatal criteria of intertwin Hb difference >8.0 g/dL and reticulocyte count ratio >1.7. Acute feto-fetal hemorrhage was defined as Hb difference >7 g/dL and reticulocyte count ratio <1.7. A total of 185 monochorionic-diamniotic twin pregnancies were included in this study. Three fulfilled the diagnostic criteria for postnatal TAPS, and one fulfilled the diagnostic criteria for acute feto-fetal hemorrhage. The incidence of spontaneous TAPS in monochorionic-diamniotic twin pregnancies was 1.6% (3/185) at Seirei Hamamatsu General Hospital. © 2014 The Authors. Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology.

  5. Eating disorders: from twin studies to candidate genes and beyond

    NARCIS (Netherlands)

    Slof-Op 't Landt, M.C.T.; Furth, E.F. van; Meulenbelt, I.; Slagboom, P.E.; Bartels, M.; Boomsma, D.I.; Bulik, C.M.

    2005-01-01

    Substantial effort has been put into the exploration of the biological background of eating disorders, through family, twin and molecular genetic studies. Family studies have shown that anorexia (AN) and bulimia nervosa (BN) are strongly familial, and that familial etiologic factors appear to be

  6. Socio-psycho-historical observation on the twin. Sampling methods and case study of the atomic bomb exposed twins

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, S; Satow, Y; Ueoka, Hiroshi; Munaka, M; Kurihara, M [Hiroshima Univ. (Japan). Research Inst. for Nuclear Medicine and Biology

    1980-07-01

    The so-called ''twin control study'', mainly on the monozygotic twins one of which was A-bomb exposed and the other was non-exposed were carried out. Sampling was conducted utilizing the materials as follows: 1) The survey on casualities of A-bomb exposed families in Hiroshima which was undertaken in 1946. 2) The survey of A-bomb survivors in 1965. 3) A-bomb exposed family survey conducted between 1973 to 1975. 4) Investigations of A-bomb victims exposed in the proximal areas from the hypocenter. From the above mentioned materials 470 pairs were selected, of which 220 were exposed. Among them 172 pairs were twins of the same sex. Female and male pair were also employed. In one case they were exposed, while the others were nonexposed. Two pairs were examined under the following methods: 1) Depth interview to ascertain familial casualities with reference to the family life cycle. 2) Socio-historical research. 3) Motoaki's Jinkaku Shindan Kensa (Modified Rorschach test by H. Motoaki), and T.A.T. test. Results obtained were summarized as follows: 1) Both pairs of twins were of similar appearance and personality traits, and had a strong feeling of companionship for each other. 2) In family relationships, the persons studied were very conscious of the role expectations of elder and younger siblings in the twin pairs. 3) Through depth interviews and projective tests, A-bomb exposed pairs still showed deep psychological stresses, resulting from the A-bomb disaster. 4) Both among the exposed twins and within the nonexposed control group twin siblings had a close feeling of companionship for each other. However, nonexposed twins could not understand the psychological experience of twins who had been subjected to the atomic disaster.

  7. Congenital Anomalies Associated with Trisomy 18 or Trisomy 13 : A Registry-Based Study in 16 European Countries, 2000-2011

    NARCIS (Netherlands)

    Springett, Anna; Wellesley, Diana; Greenlees, Ruth; Loane, Maria; Addor, Marie-Claude; Arriola, Larraitz; Bergman, Jorieke; Cavero-Carbonell, Clara; Csaky-Szunyogh, Melinda; Draper, Elizabeth S.; Garne, Ester; Gatt, Miriam; Haeusler, Martin; Khoshnood, Babak; Klungsoyr, Kari; Lynch, Catherine; Dias, Carlos Matias; McDonnell, Robert; Nelen, Vera; O'Mahony, Mary; Pierini, Anna; Queisser-Luft, Annette; Rankin, Judith; Rissmann, Anke; Rounding, Catherine; Stoianova, Sylvia; Tuckerz, David; Zymak-Zakutnia, Natalya; Morris, Joan K.

    2015-01-01

    The aim of this study was to examine the prevalence of trisomies 18 and 13 in Europe and the prevalence of associated anomalies. Twenty-five population-based registries in 16 European countries provided data from 2000-2011. Cases included live births, fetal deaths (20+ weeks' gestation), and

  8. 3-year follow-up of a long-term registry-based multicentre study on vitamin E diffused polyethylene in total hip replacement

    DEFF Research Database (Denmark)

    Sillesen, Nanna Hylleholt; Greene, Meridith E; Nebergall, Audrey K

    2016-01-01

    PURPOSE: Preclinical studies of vitamin E diffused highly cross-linked polyethylene (E-XLPE) has shown enhanced mechanical properties with less wear. The purpose of our study was to document the early clinical outcome of E-XLPE to ensure, for the safety of patients, that there are no unforeseen...... hip arthroplasty in functionality and quality of life across the centers. We have not observed any early in vivo adverse effects from diffusing the liners with vitamin E. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00545285....... early adverse events from using this new biomaterial. METHODS: The enrolled patients (n = 977) have received either a porous titanium coated or porous plasma sprayed acetabular shell with either a E-XLPE liner or a medium cross-linked (AXL) liner. At each follow-up 5 patient-reported outcome measures...

  9. Use of a prescribed ephedrine/caffeine combination and the risk of serious cardiovascular events: a registry-based case-crossover study

    DEFF Research Database (Denmark)

    Hallas, Jesper; Bjerrum, Lars; Støvring, Henrik

    2008-01-01

    Ephedrine and herbal ephedra preparations have been shown to induce a small-to-moderate weight loss. Owing to reports on serious cardiovascular events, they were banned from the US market in 2004. There have been no large controlled studies on the possible association between prescribed ephedrine/caffeine...... and cardiovascular events in general. The authors linked data from four different sources within Statistics Denmark, using data on 257,364 users of prescribed ephedrine/caffeine for the period 1995-2002. The data were analyzed using a case-crossover technique with a composite endpoint: death outside of a hospital......, myocardial infarction, or stroke. To account for effects of chronic exposure and effects in naïve users, the authors performed a secondary case-control study nested within the cohort of ephedrine/caffeine ever users. Among 2,316 case subjects, 282 (12.2%) were current users of ephedrine/caffeine. The case...

  10. Analyzing Seasonal Variations in Suicide With Fourier Poisson Time-Series Regression: A Registry-Based Study From Norway, 1969-2007.

    Science.gov (United States)

    Bramness, Jørgen G; Walby, Fredrik A; Morken, Gunnar; Røislien, Jo

    2015-08-01

    Seasonal variation in the number of suicides has long been acknowledged. It has been suggested that this seasonality has declined in recent years, but studies have generally used statistical methods incapable of confirming this. We examined all suicides occurring in Norway during 1969-2007 (more than 20,000 suicides in total) to establish whether seasonality decreased over time. Fitting of additive Fourier Poisson time-series regression models allowed for formal testing of a possible linear decrease in seasonality, or a reduction at a specific point in time, while adjusting for a possible smooth nonlinear long-term change without having to categorize time into discrete yearly units. The models were compared using Akaike's Information Criterion and analysis of variance. A model with a seasonal pattern was significantly superior to a model without one. There was a reduction in seasonality during the period. Both the model assuming a linear decrease in seasonality and the model assuming a change at a specific point in time were both superior to a model assuming constant seasonality, thus confirming by formal statistical testing that the magnitude of the seasonality in suicides has diminished. The additive Fourier Poisson time-series regression model would also be useful for studying other temporal phenomena with seasonal components. © The Author 2015. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Gonorrhoea and Syphilis Epidemiology in Flemish General Practice 2009–2013: Results from a Registry-based Retrospective Cohort Study Compared with Mandatory Notification

    Directory of Open Access Journals (Sweden)

    Christoph Schweikardt

    2016-09-01

    Full Text Available Background: The number of newly diagnosed gonorrhoea and syphilis cases has increased in Flanders in recent years. Our aim was to investigate, to which extent these diagnoses were registered by general practitioners (GPs, and to examine opportunities and limits of the Intego database in this regard. Methods: Data from a retrospective cohort study based on the Flemish Intego general practice database was analyzed for the years 2009–2013. Case definitions were applied. Due to small case numbers obtained, cases were pooled and averaged over the observation period. Frequencies were compared with those calculated from figures of mandatory notification. Results: A total of 91 gonorrhoea and 23 syphilis cases were registered. The average Intego annual frequency of gonorrhoea cases obtained was 11.9 (95% Poisson confidence interval (CI 9.6; 14.7 per 100,000 population, and for syphilis 3.0 (CI 1.9; 4.5, respectively, while mandatory notification was calculated at 14.0 (CI: 13.6, 14.4 and 7.0 (CI: 6.7, 7.3, respectively. Conclusion: In spite of limitations such as small numbers and different case definitions, comparison with mandatory notification suggests that the GP was involved in the large majority of gonorrhoea cases, while the majority of new syphilis cases did not come to the knowledge of the GP.

  12. Diabetic nephropathy and its risk factors in a society with a type 2 diabetes epidemic: a Saudi National Diabetes Registry-based study.

    Directory of Open Access Journals (Sweden)

    Khalid Al-Rubeaan

    Full Text Available The prevalence of diabetic nephropathy and its risk factors have not been studied in a society known to have diabetes epidemic like Saudi Arabia. Using a large data base registry will provide a better understanding and accurate assessment of this chronic complication and its related risk factors.A total of 54,670 patients with type 2 diabetes aged ≥ 25 years were selected from the Saudi National Diabetes Registry (SNDR and analyzed for the presence of diabetic nephropathy. The American Diabetes Association (ADA criterion was used to identify cases with microalbuminuria, macroalbuminuria and end stage renal disease (ESRD for prevalence estimation and risk factor assessment.The overall prevalence of diabetic nephropathy was 10.8%, divided into 1.2% microalbuminuria, 8.1%macroalbuninuria and 1.5% ESRD. Age and diabetes duration as important risk factors have a strong impact on the prevalence of diabetic nephropathy, ranging from 3.7% in patients aged 25-44 years and a duration of >5 years, to 21.8% in patients ≥ 65 years with a diabetes duration of ≥ 15 years. Diabetes duration, retinopathy, neuropathy, hypertension, age >45 years, hyperlipidemia, male gender, smoking, and chronologically, poor glycemic control has a significantly high risk for diabetic nephropathy.The prevalence of diabetic nephropathy is underestimated as a result of a shortage of screening programs. Risk factors related to diabetic nephropathy in this society are similar to other societies. There is thus an urgent need for screening and prevention programs for diabetic nephropathy among the Saudi population.

  13. Biodegradable-Polymer Biolimus-Eluting Stents versus Durable-Polymer Everolimus-Eluting Stents at One-Year Follow-Up: A Registry-Based Cohort Study.

    Science.gov (United States)

    Parsa, Ehsan; Saroukhani, Sepideh; Majlessi, Fereshteh; Poorhosseini, Hamidreza; Lofti-Tokaldany, Masoumeh; Jalali, Arash; Salarifar, Mojtaba; Nematipour, Ebrahim; Alidoosti, Mohammad; Aghajani, Hassan; Amirzadegan, Alireza; Kassaian, Seyed Ebrahim

    2016-04-01

    We compared outcomes of percutaneous coronary intervention patients who received biodegradable-polymer biolimus-eluting stents with those who received durable-polymer everolimus-eluting stents. At Tehran Heart Center, we performed a retrospective analysis of the data from January 2007 through December 2011 on 3,270 consecutive patients with coronary artery disease who underwent percutaneous coronary intervention with the biodegradable-polymer biolimus-eluting stent or the durable-polymer everolimus-eluting stent. We excluded patients with histories of coronary artery bypass grafting or percutaneous coronary intervention, acute ST-segment-elevation myocardial infarction, or the implantation of 2 different stent types. Patients were monitored for 12 months. The primary endpoint was a major adverse cardiac event, defined as a composite of death, nonfatal myocardial infarction, and target-vessel and target-lesion revascularization. Durable-polymer everolimus-eluting stents were implanted in 2,648 (81%) and biodegradable-polymer biolimus-eluting stents in 622 (19%) of the study population. There was no significant difference between the 2 groups (2.7% vs 2.7%; P=0.984) in the incidence of major adverse cardiac events. The cumulative adjusted probability of major adverse cardiac events in the biodegradable-polymer biolimus-eluting stent group did not differ from that of such events in the durable-polymer everolimus-eluting stent group (hazard ratio=0.768; 95% confidence interval, 0.421-1.44; P=0.388). We conclude that in our patients the biodegradable-polymer biolimus-eluting stent was as effective and safe, during the 12-month follow-up period, as was the durable-polymer everolimus-eluting stent.

  14. Barriers to cervical cancer screening faced by immigrants: a registry-based study of 1.4 million women in Norway.

    Science.gov (United States)

    Leinonen, Maarit K; Campbell, Suzanne; Ursin, Giske; Tropé, Ameli; Nygård, Mari

    2017-10-01

    Immigrants from certain low- and middle-income countries are more prone to cancers attributed to viral infections in early life. Cervical cancer is caused by human papillomavirus but is highly preventable by regular screening. We assessed participation among immigrants in a population-based cervical screening programme and identified factors that predicted non-adherence within different immigrant groups. We used data from several nationwide registries. The study population consisted of 208 626 (15%) immigrants and 1 157 223 (85%) native Norwegians. Non-adherence was defined as no eligible screening test in 2008-12. We estimated prevalence ratios with 95% confidence intervals (CIs) for factors associated with non-adherence by modified Poisson regression. In total, 52% of immigrants were not screened. All immigrants showed 1.72 times higher non-adherence rates (95% CI 1.71-1.73) compared with native Norwegian women when adjusted for age and parity. The proportion of non-adherent immigrants varied substantially by region of origin and country of origin. Being unemployed or not in the workforce, being unmarried, having low income and having a male general practitioner was associated with non-adherence regardless of region of origin. Living immigrant groups. An increasing proportion of immigrants and low screening participation among them pose new public health challenges in Europe. Immigrants are diverse in terms of their sociodemographic attributes and screening participation. Tailored information and service delivery may be necessary to increase cancer screening among immigrants. © The Author 2017. Published by Oxford University Press on behalf of the European Public Health Association.

  15. Diabetic Nephropathy and Its Risk Factors in a Society with a Type 2 Diabetes Epidemic: A Saudi National Diabetes Registry-Based Study

    Science.gov (United States)

    Al-Rubeaan, Khalid; Youssef, Amira M.; Subhani, Shazia N.; Ahmad, Najlaa A.; Al-Sharqawi, Ahmad H.; Al-Mutlaq, Hind M.; David, Satish K.; AlNaqeb, Dhekra

    2014-01-01

    Aims The prevalence of diabetic nephropathy and its risk factors have not been studied in a society known to have diabetes epidemic like Saudi Arabia. Using a large data base registry will provide a better understanding and accurate assessment of this chronic complication and its related risk factors. Methodology A total of 54,670 patients with type 2 diabetes aged ≥25 years were selected from the Saudi National Diabetes Registry (SNDR) and analyzed for the presence of diabetic nephropathy. The American Diabetes Association (ADA) criterion was used to identify cases with microalbuminuria, macroalbuminuria and end stage renal disease (ESRD) for prevalence estimation and risk factor assessment. Results The overall prevalence of diabetic nephropathy was 10.8%, divided into 1.2% microalbuminuria, 8.1%macroalbuninuria and 1.5% ESRD. Age and diabetes duration as important risk factors have a strong impact on the prevalence of diabetic nephropathy, ranging from 3.7% in patients aged 25–44 years and a duration of >5 years, to 21.8% in patients ≥65 years with a diabetes duration of ≥15 years. Diabetes duration, retinopathy, neuropathy, hypertension, age >45 years, hyperlipidemia, male gender, smoking, and chronologically, poor glycemic control has a significantly high risk for diabetic nephropathy. Conclusion The prevalence of diabetic nephropathy is underestimated as a result of a shortage of screening programs. Risk factors related to diabetic nephropathy in this society are similar to other societies. There is thus an urgent need for screening and prevention programs for diabetic nephropathy among the Saudi population. PMID:24586457

  16. Body Mass Index Class Is Independently Associated With Health-Related Quality of Life After Primary Total Hip Arthroplasty: An Institutional Registry-Based Study.

    Science.gov (United States)

    McLawhorn, Alexander S; Steinhaus, Michael E; Southren, Daniel L; Lee, Yuo-Yu; Dodwell, Emily R; Figgie, Mark P

    2017-01-01

    The purpose of this study was to compare the health-related quality of life (HRQoL) of patients across World Health Organization (WHO) body mass index (BMI) classes before and after total hip arthroplasty (THA). Patients with end-stage hip osteoarthritis who received elective primary unilateral THA were identified through an institutional registry and categorized based on the World Health Organization BMI classification. Age, sex, laterality, year of surgery, and Charlson-Deyo comorbidity index were recorded. The primary outcome was the EQ-5D-3L index and visual analog scale (EQ-VAS) scores at 2 years postoperatively. Inferential statistics and regression analyses were performed to determine associations between BMI classes and HRQoL. EQ-5D-3L scores at baseline and at 2 years were statistically different across BMI classes, with higher EQ-VAS and index scores in patients with lower BMI. There was no difference observed for the 2-year change in EQ-VAS scores, but there was a statistically greater increase in index scores for more obese patients. In the regression analyses, there were statistically significant negative effect estimates for EQ-VAS and index scores associated with increasing BMI class. BMI class is independently associated with lower HRQoL scores 2 years after primary THA. While absolute scores in obese patients were lower than in nonobese patients, obese patients enjoyed more positive changes in EQ-5D index scores after THA. These results may provide the most detailed information on how BMI influences HRQoL before and after THA, and they are relevant to future economic decision analyses on the topic. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Monitoring of timely and delayed vaccinations: a nation-wide registry-based study of Norwegian children aged < 2 years.

    Science.gov (United States)

    Riise, Øystein Rolandsen; Laake, Ida; Bergsaker, Marianne Adeleide Riise; Nøkleby, Hanne; Haugen, Inger Lise; Storsæter, Jann

    2015-11-13

    Delayed vaccinations increase the risk for vaccine preventable diseases (VPDs). Monitoring of delayed vaccinations by using a national immunisation registry has not been studied in countries recommending a two-dose (3 and 5 months of age) primary series of e.g., pertussis vaccine. Surveillance/monitoring of all vaccinations may improve vaccination programmes functioning. We obtained information from the Norwegian immunisation registry (SYSVAK) on all programme vaccinations received at age up to 730 days in children born in 2010 (n = 63,382). Timely vaccinations were received up to 7 days after the recommended age. Vaccinations were considered delayed if they were received more than one month after the recommended age in the schedule. In vaccinated children, timely administration of the subsequent three doses of pertussis and one dose of measles occurred in 73.8, 47.6, 53.6 and 43.5 % respectively. Delay for one or more programme vaccinations (diphtheria, tetanus, pertussis, polio, Haemophilus influenza type B, invasive pneumococcal disease, measles, mumps or rubella) was present in 28,336 (44.7 %) children. Among those who were delayed the mean duration was 139 days. The proportion of children that had vaccinations delayed differed among counties (range 37.4 %-57.8 %). Immigrant children were more frequently delayed 52.3 % vs. 43.1 %, RR 1.21 (95 % CI 1.19, 1.24). Children scheduled for vaccines in the summer holiday month (July) were more frequently delayed than others (1(st) dose pertussis vaccine 6.5 % vs. 3.9 % RR 1.65 (95 % CI 1.48, 1.85). Priming against pertussis (2(nd) dose), pneumococcal (2(nd) dose) and measles (1(st) dose) was delayed in 16.8, 18.6 and 29.3 % respectively. Vaccinations were frequently delayed. Delayed vaccinations differed among counties and occurred more frequently during the summer vacation (July) and in the immigrant population. Monitoring improves programme surveillance and may be used on an annual basis.

  18. Comorbidity and cervical cancer survival of Indigenous and non-Indigenous Australian women: A semi-national registry-based cohort study (2003-2012).

    Science.gov (United States)

    Diaz, Abbey; Baade, Peter D; Valery, Patricia C; Whop, Lisa J; Moore, Suzanne P; Cunningham, Joan; Garvey, Gail; Brotherton, Julia M L; O'Connell, Dianne L; Canfell, Karen; Sarfati, Diana; Roder, David; Buckley, Elizabeth; Condon, John R

    2018-01-01

    Little is known about the impact of comorbidity on cervical cancer survival in Australian women, including whether Indigenous women's higher prevalence of comorbidity contributes to their lower survival compared to non-Indigenous women. Data for cervical cancers diagnosed in 2003-2012 were extracted from six Australian state-based cancer registries and linked to hospital inpatient records to identify comorbidity diagnoses. Five-year cause-specific and all-cause survival probabilities were estimated using the Kaplan-Meier method. Flexible parametric models were used to estimate excess cause-specific mortality by Charlson comorbidity index score (0,1,2+), for Indigenous women compared to non-Indigenous women. Of 4,467 women, Indigenous women (4.4%) compared to non-Indigenous women had more comorbidity at diagnosis (score ≥1: 24.2% vs. 10.0%) and lower five-year cause-specific survival (60.2% vs. 76.6%). Comorbidity was associated with increased cervical cancer mortality for non-Indigenous women, but there was no evidence of such a relationship for Indigenous women. There was an 18% reduction in the Indigenous: non-Indigenous hazard ratio (excess mortality) when comorbidity was included in the model, yet this reduction was not statistically significant. The excess mortality for Indigenous women was only evident among those without comorbidity (Indigenous: non-Indigenous HR 2.5, 95%CI 1.9-3.4), indicating that factors other than those measured in this study are contributing to the differential. In a subgroup of New South Wales women, comorbidity was associated with advanced-stage cancer, which in turn was associated with elevated cervical cancer mortality. Survival was lowest for women with comorbidity. However, there wasn't a clear comorbidity-survival gradient for Indigenous women. Further investigation of potential drivers of the cervical cancer survival differentials is warranted. The results highlight the need for cancer care guidelines and multidisciplinary

  19. Burden of hospital admission and repeat angiography in angina pectoris patients with and without coronary artery disease: a registry-based cohort study.

    Science.gov (United States)

    Jespersen, Lasse; Abildstrom, Steen Z; Hvelplund, Anders; Madsen, Jan K; Galatius, Soren; Pedersen, Frants; Hojberg, Soren; Prescott, Eva

    2014-01-01

    To evaluate risk of hospitalization due to cardiovascular disease (CVD) and repeat coronary angiography (CAG) in stable angina pectoris (SAP) with no obstructive coronary artery disease (CAD) versus obstructive CAD, and asymptomatic reference individuals. We followed 11,223 patients with no prior CVD having a first-time CAG in 1998-2009 due to SAP symptoms and 5,695 asymptomatic reference individuals from the Copenhagen City Heart Study through registry linkage for 7.8 years (median). In recurrent event survival analysis, patients with SAP had 3-4-fold higher risk of hospitalization for CVD irrespective of CAG findings and cardiovascular comorbidity. Multivariable adjusted hazard ratios(95%CI) for patients with angiographically normal coronary arteries was 3.0(2.5-3.5), for angiographically diffuse non-obstructive CAD 3.9(3.3-4.6) and for 1-3-vessel disease 3.6-4.1(range)(all P<0.001). Mean accumulated hospitalization time was 3.5(3.0-4.0)(days/10 years follow-up) in reference individuals and 4.5(3.8-5.2)/7.0(5.4-8.6)/6.7(5.2-8.1)/6.1(5.2-7.4)/8.6(6.6-10.7) in patients with angiographically normal coronary arteries/angiographically diffuse non-obstructive CAD/1-, 2-, and 3-vessel disease, respectively (all P<0.05, age-adjusted). SAP symptoms predicted repeat CAG with multivariable adjusted hazard ratios for patients with angiographically normal coronary arteries being 2.3(1.9-2.9), for angiographically diffuse non-obstructive CAD 5.5(4.4-6.8) and for obstructive CAD 6.6-9.4(range)(all P<0.001). Patients with SAP symptoms and angiographically normal coronary arteries or angiographically diffuse non-obstructive CAD suffer from considerably greater CVD burdens in terms of hospitalization for CVD and repeat CAG compared with asymptomatic reference individuals even after adjustment for cardiac risk factors and exclusion of cardiovascular comorbidity as cause. Contrary to common perception, excluding obstructive CAD by CAG in such patients does not ensure a benign

  20. Comorbidity and cervical cancer survival of Indigenous and non-Indigenous Australian women: A semi-national registry-based cohort study (2003-2012.

    Directory of Open Access Journals (Sweden)

    Abbey Diaz

    Full Text Available Little is known about the impact of comorbidity on cervical cancer survival in Australian women, including whether Indigenous women's higher prevalence of comorbidity contributes to their lower survival compared to non-Indigenous women.Data for cervical cancers diagnosed in 2003-2012 were extracted from six Australian state-based cancer registries and linked to hospital inpatient records to identify comorbidity diagnoses. Five-year cause-specific and all-cause survival probabilities were estimated using the Kaplan-Meier method. Flexible parametric models were used to estimate excess cause-specific mortality by Charlson comorbidity index score (0,1,2+, for Indigenous women compared to non-Indigenous women.Of 4,467 women, Indigenous women (4.4% compared to non-Indigenous women had more comorbidity at diagnosis (score ≥1: 24.2% vs. 10.0% and lower five-year cause-specific survival (60.2% vs. 76.6%. Comorbidity was associated with increased cervical cancer mortality for non-Indigenous women, but there was no evidence of such a relationship for Indigenous women. There was an 18% reduction in the Indigenous: non-Indigenous hazard ratio (excess mortality when comorbidity was included in the model, yet this reduction was not statistically significant. The excess mortality for Indigenous women was only evident among those without comorbidity (Indigenous: non-Indigenous HR 2.5, 95%CI 1.9-3.4, indicating that factors other than those measured in this study are contributing to the differential. In a subgroup of New South Wales women, comorbidity was associated with advanced-stage cancer, which in turn was associated with elevated cervical cancer mortality.Survival was lowest for women with comorbidity. However, there wasn't a clear comorbidity-survival gradient for Indigenous women. Further investigation of potential drivers of the cervical cancer survival differentials is warranted.The results highlight the need for cancer care guidelines and

  1. Socioeconomic disparities in first stroke incidence, quality of care, and survival: a nationwide registry-based cohort study of 44 million adults in England

    Directory of Open Access Journals (Sweden)

    Benjamin D Bray, MD

    2018-04-01

    Full Text Available Summary: Background: We aimed to estimate socioeconomic disparities in the incidence of hospitalisation for first-ever stroke, quality of care, and post-stroke survival for the adult population of England. Methods: In this cohort study, we obtained data collected by a nationwide register on patients aged 18 years or older hospitalised for first-ever acute ischaemic stroke or primary intracerebral haemorrhage in England from July 1, 2013, to March 31, 2016. We classified socioeconomic status at the level of Lower Super Output Areas using the Index of Multiple Deprivation, a neighbourhood measure of deprivation. Multivariable models were fitted to estimate the incidence of hospitalisation for first stroke (negative binomial, quality of care using 12 quality metrics (multilevel logistic, and all-cause 1 year case fatality (Cox proportional hazards. Findings: Of the 43·8 million adults in England, 145 324 were admitted to hospital with their first-ever stroke: 126 640 (87% with ischaemic stroke, 17 233 (12% with intracerebral haemorrhage, and 1451 (1% with undetermined stroke type. We observed a socioeconomic gradient in the incidence of hospitalisation for ischaemic stroke (adjusted incidence rate ratio 2·0, 95% CI 1·7–2·3 for the most vs least deprived deciles and intracerebral haemorrhage (1·6, 1·3–1·9. Patients from the lowest socioeconomic groups had first stroke a median of 7 years earlier than those from the highest (p<0·0001, and had a higher prevalence of pre-stroke disability and diabetes. Patients from lower socioeconomic groups were less likely to receive five of 12 care processes but were more likely to receive early supported discharge (adjusted odds ratio 1·14, 95% CI 1·07–1·22. Low socioeconomic status was associated with a 26% higher adjusted risk of 1-year mortality (adjusted hazard ratio 1·26, 95% CI 1·20–1·33, for highest vs lowest deprivation decile, but this gradient was largely attenuated after

  2. Risk Factors Influencing Smoking Behavior: A Turkish Twin Study

    Science.gov (United States)

    Öncel, Sevgi Yurt; Dick, Danielle M.; Maes, Hermine H.; Alıev, Fazil

    2015-01-01

    Aim In this study, we introduce the first twin study in Turkey, focusing on smoking behavior, and laying the foundation to register all twins born in Turkey for research purposes. Using Turkish twins will contribute to our understanding of health problems in the context of cultural differences. Materials and methods We assessed 309 twin pairs (339 males and 279 females) aged between 15 and 45 years living in the Kırıkkale and Ankara regions of Turkey, and administered a health and lifestyle interview that included questions about smoking status and smoking history. We analyzed the data using descriptive statistics, t-tests, chi-square tests, and bivariate and multivariate clustered logistic regression. In addition, we fit bivariate Structural Equation Models (SEM) to determine contributions of latent genetic and environmental factors to smoking outcomes in this sample. Results One hundred seventy-eight participants (28.8%) were identified as smokers, smoking every day for a month or longer, of whom 79.2% were males and 20.8% were females. Mean values for number of cigarettes per day and the Fagerstrom Test of Nicotine Dependence (FTND; Fagerstrom, 1978) score were higher in males than in females, and age of onset was earlier in males. There was a significant positive correlation between the FTND score and number of cigarettes smoked per day, and a significant negative correlation between both variables and age at onset of smoking. Our study showed that gender, presence of a smoking twin in the family, age, alcohol use, marital status, daily sports activities, and feeling moody all played a significant role in smoking behavior among twins. The twin analysis suggested that 79.5% of the liability to FTND was influenced by genetic factors and 20.5% by unique environment, while familial resemblance for smoking initiation was best explained by common environmental factors. Conclusions Marked differences in the prevalence of smoking behavior in men versus women were

  3. Outcome reporting across randomised trials and observational studies evaluating treatments for Twin-Twin Transfusion Syndrome: a systematic review.

    Science.gov (United States)

    Perry, Helen; Duffy, James M N; Umadia, Ogochukwu; Khalil, Asma

    2018-04-01

    Twin-Twin Transfusion syndrome is associated with significant mortality and morbidity. Potential treatments require robust evaluation. The aim of this study was to evaluate outcome reporting across observational studies and randomised controlled trials assessing treatments for twin-twin transfusion syndrome (TTTS). Cochrane Central Register of Controlled Trials, EMBASE and Medline were searched from inception to August 2016. Observational studies and randomised controlled trials reporting outcomes following a treatment for TTTS in monochorionic-diamniotic twin pregnancies and monochorionic-triamniotic or dichorionic-triamniotic triplet pregnancies were included. We systematically extracted and categorised outcome reporting. Six randomised trials and 94 observational studies, reporting data from 20,071 maternal participants and 3,199 children, were included. Six different treatments were evaluated. Included studies reported sixty-two different outcomes, including 10 fetal, 28 neonatal, 6 early childhood and 18 maternal outcomes. The outcomes were inconsistently reported across trials. For example, when considering offspring mortality, 31 studies (31%) reported live birth, 31 studies (31%) reported intrauterine death, 49 studies (49%) reported neonatal mortality, and 17 studies (17%) reported perinatal mortality. Four studies (4%) reported respiratory distress syndrome. Only 19 (19%) of studies were designed for long-term follow-up and 11 of these studies (11%) reported cerebral palsy. Most studies evaluating treatments for TTTS, have often neglected to report clinically important outcomes, especially neonatal morbidity outcomes. Most studies are not designed for long-term follow-up. The development of a core outcome set could help standardised outcome collection and reporting in Twin-Twin Transfusion syndrome studies. This article is protected by copyright. All rights reserved.

  4. A twin study of specific bulimia nervosa symptoms.

    Science.gov (United States)

    Mazzeo, S E; Mitchell, K S; Bulik, C M; Aggen, S H; Kendler, K S; Neale, M C

    2010-07-01

    Twin studies have suggested that additive genetic factors significantly contribute to liability to bulimia nervosa (BN). However, the diagnostic criteria for BN remain controversial. In this study, an item-factor model was used to examine the BN diagnostic criteria and the genetic and environmental contributions to BN in a population-based twin sample. The validity of the equal environment assumption (EEA) for BN was also tested. Participants were 1024 female twins (MZ n=614, DZ n=410) from the population-based Mid-Atlantic Twin Registry. BN was assessed using symptom-level (self-report) items consistent with DSM-IV and ICD-10 diagnostic criteria. Items assessing BN were included in an item-factor model. The EEA was measured by items assessing similarity of childhood and adolescent environment, which have demonstrated construct validity. Scores on the EEA factor were used to specify the degree to which twins shared environmental experiences in this model. The EEA was not violated for BN. Modeling results indicated that the majority of the variance in BN was due to additive genetic factors. There was substantial variability in additive genetic and environmental contributions to specific BN symptoms. Most notably, vomiting was very strongly influenced by additive genetic factors, while other symptoms were much less heritable, including the influence of weight on self-evaluation. These results highlight the importance of assessing eating disorders at the symptom level. Refinement of eating disorder phenotypes could ultimately lead to improvements in treatment and targeted prevention, by clarifying sources of variation for specific components of symptomatology.

  5. The Heritability of Breast Cancer among women in the Nordic Twin Study of Cancer

    DEFF Research Database (Denmark)

    Möller, Sören; Mucci, Lorelei A; Harris, Jennifer R

    2016-01-01

    and heritability of breast cancer among 21,054 monozygotic and 30,939 dizygotic female twin pairs from the Nordic Twin Study of Cancer, the largest twin study of cancer in the world. We accounted for left-censoring, right-censoring, as well as the competing risk of death. Results From 1943 through 2010, 3...

  6. A twin study of the trough plasma steady-state concentration of metformin

    DEFF Research Database (Denmark)

    Stage, Tore B; Damkier, Per; Pedersen, Rasmus S

    2015-01-01

    OBJECTIVE: The aim of this study was to determine the intrapair similarity in trough steady-state plasma concentrations of metformin in monozygotic and dizygotic twin pairs. METHODS: We included 16 twin pairs (eight monozygotic and eight dizygotic twin pairs) for this study after contacting 524 t...

  7. Multifactorial etiology of Torus mandibularis: study of twins.

    Science.gov (United States)

    Auškalnis, Adomas; Rutkūnas, Vygandas; Bernhardt, Olaf; Šidlauskas, Mantas; Šalomskienė, Loreta; Basevičienė, Nomeda

    2015-01-01

    The aim of this study is to investigate the multifactorial etiology of mandibular tori analyzing the influence of genetics, occlusal overload, various clinical variables and their interactions. Overall, plaster casts of 162 twins (81 twin pairs) were analyzed for the presence or absence of mandibular tori. Atypical wear facets on canine tips or incisors were recorded to diagnose bruxism. Angle Class, any kind of anterior open bite and positive, negative or flat curve of Wilson were recorded. Zygosity determination was carried out using a DNA test. Mandibular tori were found in 56.8% of the cases. In 93.6% of all monozygotic twin pairs both individuals had or did not have mandibular tori (κ=0.96±0.04; p<0.001), compared to 79.4% concordance of mandibular tori in dizygotic co-twins (κ=0.7±0.12; p<0.001). Prevalence of mandibular tori was significantly higher in the group of bruxers (67.5%) compared to non-bruxers (31.3%) (p<0.001). Significant association between mandibular tori and negative or flat curve of Wilson in the maxillary second premolars and first molars was found (OR=2.55, 95% CI (1.19-5.46), p=0.016). In all monozygotic bruxers, 97.1% showed concordance of mandibular tori presence in both co-twins compared to 78.9% dizygotic bruxers, and this difference is statistically significant (p=0.007). Our results suggest that the mandibular tori are of a multifactorial origin. Mandibular tori seem to have genetic predisposition, and may be associated with teeth grinding as well as with negative or flat CW in region of maxillary second premolar and first molar.

  8. Effect of maternal smoking on birth weight of twins: a study from the Dutch Twin Register

    NARCIS (Netherlands)

    Orlebeke, J.F.; Boomsma, D.I.; van Baal, G.C.M.; Bleker, O.P.

    1994-01-01

    Since twins weigh about 20% less than singletons at birth, maternal smoking may be a more severe risk for them than for singletons. Therefore, the effect of maternal smoking during pregnancy on birth weight was investigated in a group of 5376 twins. All necessary information was collected by a

  9. Twin and grain boundary in InP: A synchrotron radiation study

    International Nuclear Information System (INIS)

    Han, Y.; Liu, X.; Jiao, J.; Lin, L.; Jiang, J.; Wang, Z.; Tian, Y.

    1998-01-01

    Experimentally observed X-ray reflectivity curves show bi-crystal(twin) characteristics. The study revealed that there was defect segregation at the twin boundary. Stress was relaxed at the edge of the boundary. Relaxation of the stress resulted in formation of twin and other defects. As a result of formation of such defects, a defect-free and stress-free zone or low defect density and small stress zone is created around the defects. So a twin model was proposed to explain the experimental results. Stress(mainly thermal stress), chemical stoichiometry deviation and impurities nonhomogeneous distributions are the key factors that cause twins in LEC InP crystal growth. Twins on (111) face in LEC InP crystal were studied. Experimental evidence of above mentioned twin model and suggestions on how to get twin-free LEC InP single crystals will be discussed

  10. The Fourth International Network of Twin Registries: Overview from Osaka/Research Reviews: Familial Fraternal Twinning; Twin Study of Masculine Faces; Physical Aggression and Epigenetics; Prenatal Education for Parents of Twins/Current Events: 2016 Guinness Book of World Records; Oldest Living Male Twins; Twins Reunited at Sixty-Nine; Panda Twins; Twins.com.

    Science.gov (United States)

    Segal, Nancy L

    2015-12-01

    The 4th International Network of Twin Registries (INTR) Consortium Meeting took place in Osaka, Japan, September 28-29, 2015. The venue was the Osaka Medical Center for Medical Innovation and Translational Research. An overview of presentations and other activities is provided. Next, 1930s research on familial fraternal twinning, preference for masculine faces, physical aggression and epigenetics, and a prenatal education program for parents of multiples are described. Current twin-related events include the 2016 Guinness Book of World Records (GWR), the oldest living male twins, newly reunited twins, the birth of panda twins and a controversial twin-based website.

  11. Ethical aspects of registry-based research in the Nordic countries.

    Science.gov (United States)

    Ludvigsson, Jonas F; Håberg, Siri E; Knudsen, Gun Peggy; Lafolie, Pierre; Zoega, Helga; Sarkkola, Catharina; von Kraemer, Stephanie; Weiderpass, Elisabete; Nørgaard, Mette

    2015-01-01

    National health care registries in the Nordic countries share many attributes, but different legal and ethical frameworks represent a challenge to promoting effective joint research. Internationally, there is a lack of knowledge about how ethical matters are considered in Nordic registry-based research, and a lack of knowledge about how Nordic ethics committees operate and what is needed to obtain an approval. In this paper, we review ethical aspects of registry-based research, the legal framework, the role of ethics review boards in the Nordic countries, and the structure of the ethics application. We discuss the role of informed consent in registry-based research and how to safeguard the integrity of study participants, including vulnerable subjects and children. Our review also provides information on the different government agencies that contribute registry-based data, and a list of the major health registries in Denmark, Finland, Iceland, Norway, and Sweden. Both ethical values and conditions for registry-based research are similar in the Nordic countries. While Denmark, Finland, Iceland, Norway, and Sweden have chosen different legal frameworks, these differences can be resolved through mutual recognition of ethical applications and by harmonizing the different systems, likely leading to increased collaboration and enlarged studies.

  12. A registry-based follow-up study, comparing the incidence of cardiovascular disease in native Danes and immigrants born in Turkey, Pakistan and the former Yugoslavia: do social inequalities play a role?

    Directory of Open Access Journals (Sweden)

    Andreasen Anne H

    2011-08-01

    Full Text Available Abstract Background This study compared the incidence of cardiovascular disease (CVD and acute myocardial infarction (AMI between native Danes and immigrants born in Turkey, Pakistan and the former Yugoslavia. Furthermore, we examined whether different indicators of socioeconomic status (SES, such as employment, income and housing conditions influenced potential differences. Methods In this registry-based follow-up study individuals were identified in a large database that included individuals from two major regions in Denmark, corresponding to about 60% of the Danish population. Incident cases of CVD and AMI included fatal and non-fatal events and were taken from registries. Using Cox regression models, we estimated incidence rates at 5-year follow-up. Results Immigrant men and women from Turkey and Pakistan had an increased incidence of CVD, compared with native Danish men. In the case of AMI, a similar pattern was observed; however, differences were more pronounced. Pakistanis and Turks with a shorter duration of residence had a lower incidence, compared with those of a longer residence. Generally, no notable differences were observed between former Yugoslavians and native Danes. In men, differences in CVD and AMI were reduced after adjustment for SES, in particular, among Turks regarding CVD. In women, effects were particularly reduced among Yugoslavians in the case of CVD and in Turks in the case of CVD and AMI after adjustment for SES. Conclusions In conclusion, country of birth-related differences in the incidence of CVD and AMI were observed. At least some of the differences that we uncovered were results of a socioeconomic effect. Duration of residence also played a certain role. Future studies should collect and test different indicators of SES in studies of CVD among immigrants.

  13. A prospective study of twinning and perinatal mortality in urban Guinea-Bissau

    Directory of Open Access Journals (Sweden)

    Bjerregaard-Andersen Morten

    2012-12-01

    Full Text Available Abstract Background Despite twinning being common in Africa, few prospective twin studies have been conducted. We studied twinning rate, perinatal mortality and the clinical characteristics of newborn twins in urban Guinea-Bissau. Methods The study was conducted at the Bandim Health Project (BHP, a health and demographic surveillance site in Bissau, the capital of Guinea-Bissau. The cohort included all newborn twins delivered at the National Hospital Simão Mendes and in the BHP study area during the period September 2009 to August 2011 as well as singleton controls from the BHP study area. Data regarding obstetric history and pregnancy were collected at the hospital. Live children were examined clinically. For a subset of twin pairs zygosity was established by using genetic markers. Results Out of the 5262 births from mothers included in the BHP study area, 94 were twin births, i.e. a community twinning rate of 18/1000. The monozygotic rate was 3.4/1000. Perinatal mortality among twins vs. singletons was 218/1000 vs. 80/1000 (RR = 2.71, 95% CI: 1.93-3.80. Among the 13783 hospital births 388 were twin births (28/1000. The hospital perinatal twin mortality was 237/1000. Birth weight  Conclusions Twins had a very high perinatal mortality, three-fold higher than singletons. A birth weight 

  14. Bidirectional Influences between Maternal Parenting and Children's Peer Problems: A Longitudinal Monozygotic Twin Difference Study

    Science.gov (United States)

    Yamagata, Shinji; Takahashi, Yusuke; Ozaki, Koken; Fujisawa, Keiko K.; Nonaka, Koichi; Ando, Juko

    2013-01-01

    This twin study examined the bidirectional relationship between maternal parenting behaviors and children's peer problems that were not confounded by genetic and family environmental factors. Mothers of 259 monozygotic twin pairs reported parenting behaviors and peer problems when twins were 42 and 48 months. Path analyses on monozygotic twin…

  15. A prospective study of twinning and perinatal mortality in urban Guinea-Bissau

    DEFF Research Database (Denmark)

    Bjerregaard-Andersen, Morten; Lund, Najaaraq; Jepsen, Frida Staarup

    2012-01-01

    ABSTRACT: BACKGROUND: Despite twinning being common in Africa, few prospective twin studies have been conducted. We studied twinning rate, perinatal mortality and the clinical characteristics of newborn twins in urban Guinea-Bissau. METHODS: The study was conducted at the Bandim Health Project (BHP......), a health and demographic surveillance site in Bissau, the capital of Guinea-Bissau. The cohort included all newborn twins delivered at the National Hospital Simao Mendes and in the BHP study area during the period September 2009 to August 2011 as well as singleton controls from the BHP study area. Data...... regarding obstetric history and pregnancy were collected at the hospital. Live children were examined clinically. For a subset of twin pairs zygosity was established by using genetic markers. RESULTS: Out of the 5262 births from mothers included in the BHP study area, 94 were twin births, i.e. a community...

  16. A twin study of perfume-related respiratory symptoms

    DEFF Research Database (Denmark)

    Elberling, J; Lerbaek, A; Kyvik, K O

    2009-01-01

    Respiratory symptoms from environmental perfume exposure are main complaints in patients with multiple chemical sensitivities and often coincide with asthma and or eczema. In this population-based twin study we estimate the heritability of respiratory symptoms related to perfume and if co......-occurrences of the symptoms in asthma, atopic dermatitis, hand eczema or contact allergy are influenced by environmental or genetic factors common with these diseases. In total 4,128 twin individuals (82%) responded to a questionnaire. The heritability of respiratory symptoms related to perfume is 0.35, 95%CI 0.......14-0.54. Significant associations (prespiratory symptoms and asthma, atopic dermatitis, hand eczema or contact allergy are not attributable to shared genetic or shared environmental/familial factors, except possibly for atopic dermatitis where genetic pleiotropy with respiratory symptoms...

  17. A twin study of perfume-related respiratory symptoms.

    Science.gov (United States)

    Elberling, J; Lerbaek, A; Kyvik, K O; Hjelmborg, J

    2009-11-01

    Respiratory symptoms from environmental perfume exposure are main complaints in patients with multiple chemical sensitivities and often coincide with asthma and or eczema. In this population-based twin study we estimate the heritability of respiratory symptoms related to perfume and if co-occurrences of the symptoms in asthma, atopic dermatitis, hand eczema or contact allergy are influenced by environmental or genetic factors common with these diseases. In total 4,128 twin individuals (82%) responded to a questionnaire. The heritability of respiratory symptoms related to perfume is 0.35, 95%CI 0.14-0.54. Significant associations (pperfume-related respiratory symptoms and asthma, atopic dermatitis, hand eczema or contact allergy are not attributable to shared genetic or shared environmental/familial factors, except possibly for atopic dermatitis where genetic pleiotropy with respiratory symptoms to perfume is suggested by an estimated genetic correlation of 0.39, 95%CI 0.09-0.72.

  18. Attachment to Inanimate Objects and Early Childcare: A Twin Study

    Directory of Open Access Journals (Sweden)

    Keren eFortuna

    2014-05-01

    Full Text Available Extensive nonmaternal childcare plays an important role in children's development. This study examined a potential coping mechanism for dealing with daily separation from caregivers involved in childcare experience—children's development of attachments toward inanimate objects. We employed the twin design to estimate relative environmental and genetic contributions to the presence of object attachment, and assess whether childcare explains some of the environmental variation in this developmental phenomenon. Mothers reported about 1122 3-year-old twin pairs. Variation in object attachment was accounted for by heritability (48% and shared environment (48%, with childcare quantity accounting for 2.2% of the shared environment effect. Children who spent half-days in childcare were significantly less likely to attach to objects relative to children who attended full-day childcare.

  19. Perinatal outcome of monochorionic and dichorionic twins after spontaneous and assisted conception: a retrospective cohort study.

    Science.gov (United States)

    Hack, Karien E A; Vereycken, Marijn E M S; Torrance, Helen L; Koopman-Esseboom, Corine; Derks, Jan B

    2018-06-01

    The aim of this study was to compare pregnancy outcomes in twin pregnancies after assisted conception and spontaneous conception, according to chorionicity. Retrospective cohort study of 1305 twin pregnancies between 1995 and 2015. All spontaneous (n = 731) and assisted conception conceived (n = 574) twin pregnancies with antenatal care and delivery in University Medical Center Utrecht, the Netherlands, a tertiary obstetric care center were studied according to chorionicity. Maternal age and incidence of nulliparity were higher among the assisted conception twins. Hypertensive disorders also appeared to be more frequent in assisted conception pregnancies, which could largely be explained by the higher proportion of elderly nulliparous women in this group. Spontaneously conceived twins were born earlier than twins after assisted conception, with subsequent lower birthweights and more admissions to a neonatal intensive care unit with increased neonatal morbidity. Monochorionic twins had worse pregnancy outcomes compared with dichorionic twins, irrespective of mode of conception; monochorionic twins conceived by assisted reproduction had more neonatal morbidity (mainly respiratory distress syndrome and necrotizing enterocolitis) and late neonatal deaths compared with spontaneously conceived monochorionic twins. Spontaneously conceived twins have worse pregnancy outcome compared with twins after assisted conception, probably due to a lower incidence of monochorionicity in the assisted conception group. The already increased perinatal risks in monochorionic twins are even higher in monochorionic twins conceived after infertility treatments compared with spontaneously conceived monochorionic twins, which warrants extra attention to these high-risk pregnancies. © 2018 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).

  20. Heritability of tic disorders: a twin-family study.

    Science.gov (United States)

    Zilhão, N R; Olthof, M C; Smit, D J A; Cath, D C; Ligthart, L; Mathews, C A; Delucchi, K; Boomsma, D I; Dolan, C V

    2017-04-01

    Genetic-epidemiological studies that estimate the contributions of genetic factors to variation in tic symptoms are scarce. We estimated the extent to which genetic and environmental influences contribute to tics, employing various phenotypic definitions ranging between mild and severe symptomatology, in a large population-based adult twin-family sample. In an extended twin-family design, we analysed lifetime tic data reported by adult mono- and dizygotic twins (n = 8323) and their family members (n = 7164; parents and siblings) from 7311 families in the Netherlands Twin Register. We measured tics by the abbreviated version of the Schedule for Tourette and Other Behavioral Syndromes. Heritability was estimated by genetic structural equation modeling for four tic disorder definitions: three dichotomous and one trichotomous phenotype, characterized by increasingly strictly defined criteria. Prevalence rates of the different tic disorders in our sample varied between 0.3 and 4.5% depending on tic disorder definition. Tic frequencies decreased with increasing age. Heritability estimates varied between 0.25 and 0.37, depending on phenotypic definitions. None of the phenotypes showed evidence of assortative mating, effects of shared environment or non-additive genetic effects. Heritabilities of mild and severe tic phenotypes were estimated to be moderate. Overlapping confidence intervals of the heritability estimates suggest overlapping genetic liabilities between the various tic phenotypes. The most lenient phenotype (defined only by tic characteristics, excluding criteria B, C and D of DSM-IV) rendered sufficiently reliable heritability estimates. These findings have implications in phenotypic definitions for future genetic studies.

  1. Genetic and environmental contributions to pro-social attitudes: a twin study of social responsibility.

    Science.gov (United States)

    Rushton, J Philippe

    2004-12-22

    Although 51 twin and adoption studies have been performed on the genetic architecture of antisocial behaviour, only four previous studies have examined a genetic contribution to pro-social behaviour. Earlier work by the author with the University of London Institute of Psychiatry Adult Twin Register found that genes contributed approximately half of the variance to measures of self-report altruism, empathy, nurturance and aggression, including acts of violence. The present study extends those results by using a 22-item Social Responsibility Questionnaire with 174 pairs of monozygotic twins and 148 pairs of dizygotic twins. Forty-two per cent of the reliable variance was due to the twins' genes, 23% to the twins' common environment and the remainder to the twins' non-shared environment.

  2. Musical activity and emotional competence – a twin study

    Directory of Open Access Journals (Sweden)

    Tores PG Theorell

    2014-07-01

    Full Text Available The hypothesis was tested that musical creative achievement and musical practice are associated with lower alexithymia. 8000 Swedish twins aged 27-54 were studied. Alexithymia was assessed using the Toronto Alexithymia Scale (TAS-20. Musical achievement was rated on a 7-graded scale. Participants estimated number of hours of music practice during different ages throughout life. A total life estimation of number of accumulated hours was made. They were also asked about ensemble playing. In addition, twin modelling was used to explore the genetic architecture of the relation between musical practice and alexithymia. Alexithymia was negatively associated with (i musical creative achievement, (ii having played a musical instrument as compared to never having played, and – for the subsample of participants that had played an instrument – (iii total hours of musical training (r = -.12 – in men and -.10 in women. Ensemble playing added significant variance. Twin modelling showed that alexithymia had a moderate heritability of 36% and that the association with musical practice could be explained by shared genetic influences. Associations between musical training and alexithymia remained significant when controlling for education, depression, and intelligence. Musical achievement and musical practice are associated with lower levels of alexithymia in both men and women. Musical engagement thus appears to be associated with higher emotional competence, although effect sizes are small. The association between musical training and alexithymia appears to be entirely genetically mediated, suggesting genetic pleiotropy.

  3. The etiology of social aggression: a nuclear twin family study.

    Science.gov (United States)

    Slawinski, Brooke L; Klump, Kelly L; Burt, S Alexandra

    2018-04-02

    Social aggression is a form of antisocial behavior in which social relationships and social status are used to damage reputations and inflict emotional harm on others. Despite extensive research examining the prevalence and consequences of social aggression, only a few studies have examined its genetic-environmental etiology, with markedly inconsistent results. We estimated the etiology of social aggression using the nuclear twin family (NTF) model. Maternal-report, paternal-report, and teacher-report data were collected for twin social aggression (N = 1030 pairs). We also examined the data using the classical twin (CT) model to evaluate whether its strict assumptions may have biased previous heritability estimates. The best-fitting NTF model for all informants was the ASFE model, indicating that additive genetic, sibling environmental, familial environmental, and non-shared environmental influences significantly contribute to the etiology of social aggression in middle childhood. However, the best-fitting CT model varied across informants, ranging from AE and ACE to CE. Specific heritability estimates for both NTF and CT models also varied across informants such that teacher reports indicated greater genetic influences and father reports indicated greater shared environmental influences. Although the specific NTF parameter estimates varied across informants, social aggression generally emerged as largely additive genetic (A = 0.15-0.77) and sibling environmental (S = 0.42-0.72) in origin. Such findings not only highlight an important role for individual genetic risk in the etiology of social aggression, but also raise important questions regarding the role of the environment.

  4. Musical activity and emotional competence - a twin study.

    Science.gov (United States)

    Theorell, Töres P; Lennartsson, Anna-Karin; Mosing, Miriam A; Ullén, Fredrik

    2014-01-01

    The hypothesis was tested that musical activities may contribute to the prevention of alexithymia. We tested whether musical creative achievement and musical practice are associated with lower alexithymia. 8000 Swedish twins aged 27-54 were studied. Alexithymia was assessed using the Toronto Alexithymia Scale-20. Musical achievement was rated on a 7-graded scale. Participants estimated number of hours of music practice during different ages throughout life. A total life estimation of number of accumulated hours was made. They were also asked about ensemble playing. In addition, twin modelling was used to explore the genetic architecture of the relation between musical practice and alexithymia. Alexithymia was negatively associated with (i) musical creative achievement, (ii) having played a musical instrument as compared to never having played, and - for the subsample of participants that had played an instrument - (iii) total hours of musical training (r = -0.12 in men and -0.10 in women). Ensemble playing added significant variance. Twin modelling showed that alexithymia had a moderate heritability of 36% and that the association with musical practice could be explained by shared genetic influences. Associations between musical training and alexithymia remained significant when controlling for education, depression, and intelligence. Musical achievement and musical practice are associated with lower levels of alexithymia in both men and women. Musical engagement thus appears to be associated with higher emotional competence, although effect sizes are small. The association between musical training and alexithymia appears to be entirely genetically mediated, suggesting genetic pleiotropy.

  5. Functional principles of registry-based service discovery

    NARCIS (Netherlands)

    Sundramoorthy, V.; Tan, C.; Hartel, P.H.; Hartog, den J.I.; Scholten, J.

    2005-01-01

    As Service Discovery Protocols (SDP) are becoming increasingly important for ubiquitous computing, they must behave according to predefined principles. We present the functional Principles of Service Discovery for robust, registry-based service discovery. A methodology to guarantee adherence to

  6. A Twin Study of Perthes Disease

    DEFF Research Database (Denmark)

    Metcalfe, David; Van Dijck, Stephanie; Parsons, Nicolas

    2016-01-01

    BACKGROUND: Legg-Calvé-Perthes disease (LCPD) is an idiopathic avascular necrosis of the femoral head. Its etiology is poorly understood, although previous studies have implicated low birth weight and possible genetic determinants. The aim of this study was to identify potential birth weight...

  7. Twin-Twin Transfusion Syndrome: study protocol for developing, disseminating, and implementing a core outcome set.

    Science.gov (United States)

    Khalil, Asma; Perry, Helen; Duffy, James; Reed, Keith; Baschat, Ahmet; Deprest, Jan; Hecher, Kurt; Lewi, Liesbeth; Lopriore, Enrico; Oepkes, Dick

    2017-07-14

    Twin-Twin Transfusion Syndrome (TTTS) is associated with an increased risk of perinatal mortality and morbidity. Several treatment interventions have been described for TTTS, including fetoscopic laser surgery, amnioreduction, septostomy, expectant management, and pregnancy termination. Over the last decade, fetoscopic laser surgery has become the primary treatment. The literature to date reports on many different outcomes, making it difficult to compare results or combine data from individual studies, limiting the value of research to guide clinical practice. With the advent and ongoing development of new therapeutic techniques, this is more important than ever. The development and use of a core outcome set has been proposed to address these issues, prioritising outcomes important to the key stakeholders, including patients. We aim to produce, disseminate, and implement a core outcome set for TTTS. An international steering group has been established to oversee the development of this core outcome set. This group includes healthcare professionals, researchers and patients. A systematic review is planned to identify previously reported outcomes following treatment for TTTS. Following completion, the identified outcomes will be evaluated by stakeholders using an international, multi-perspective online modified Delphi method to build consensus on core outcomes. This method encourages the participants towards consensus 'core' outcomes. All key stakeholders will be invited to participate. The steering group will then hold a consensus meeting to discuss results and form a core outcome set to be introduced and measured. Once core outcomes have been agreed, the next step will be to determine how they should be measured, disseminated, and implemented within an international context. The development, dissemination, and implementation of a core outcome set in TTTS will enable its use in future clinical trials, systematic reviews and clinical practice guidelines. This is

  8. Familial Risk and Heritability of Colorectal Cancer in the Nordic Twin Study of Cancer

    DEFF Research Database (Denmark)

    Graff, Rebecca E; Möller, Sören; Passarelli, Michael N

    2017-01-01

    included 39,990 monozygotic and 61,443 same-sex dizygotic twins from the Nordic Twin Study of Cancer. We compared each cancer's risk in twins of affected co-twins relative to the cohort risk (familial risk ratio; FRR). We then estimated the proportion of variation in risk that could be attributed......BACKGROUND & AIMS: We analyzed data from twins to determine how much the familial risk of colorectal cancer can be attributed to genetic factors vs environment. We also examined whether heritability is distinct for colon vs rectal cancer, given evidence of distinct etiologies. METHODS: Our data set...... to genetic factors (heritability). RESULTS: From earliest registration in 1943 through 2010, 1861 individuals were diagnosed with colon cancer and 1268 with rectal cancer. Monozygotic twins of affected co-twins had an FRR for colorectal cancer of 3.1 (95% CI, 2.4-3.8) relative to the cohort risk. Dizygotic...

  9. A registry-based randomized trial comparing radial and femoral approaches in women undergoing percutaneous coronary intervention: the SAFE-PCI for Women (Study of Access Site for Enhancement of PCI for Women) trial.

    Science.gov (United States)

    Rao, Sunil V; Hess, Connie N; Barham, Britt; Aberle, Laura H; Anstrom, Kevin J; Patel, Tejan B; Jorgensen, Jesse P; Mazzaferri, Ernest L; Jolly, Sanjit S; Jacobs, Alice; Newby, L Kristin; Gibson, C Michael; Kong, David F; Mehran, Roxana; Waksman, Ron; Gilchrist, Ian C; McCourt, Brian J; Messenger, John C; Peterson, Eric D; Harrington, Robert A; Krucoff, Mitchell W

    2014-08-01

    This study sought to determine the effect of radial access on outcomes in women undergoing percutaneous coronary intervention (PCI) using a registry-based randomized trial. Women are at increased risk of bleeding and vascular complications after PCI. The role of radial access in women is unclear. Women undergoing cardiac catheterization or PCI were randomized to radial or femoral arterial access. Data from the CathPCI Registry and trial-specific data were merged into a final study database. The primary efficacy endpoint was Bleeding Academic Research Consortium type 2, 3, or 5 bleeding or vascular complications requiring intervention. The primary feasibility endpoint was access site crossover. The primary analysis cohort was the subgroup undergoing PCI; sensitivity analyses were conducted in the total randomized population. The trial was stopped early for a lower than expected event rate. A total of 1,787 women (691 undergoing PCI) were randomized at 60 sites. There was no significant difference in the primary efficacy endpoint between radial or femoral access among women undergoing PCI (radial 1.2% vs. 2.9% femoral, odds ratio [OR]: 0.39; 95% confidence interval [CI]: 0.12 to 1.27); among women undergoing cardiac catheterization or PCI, radial access significantly reduced bleeding and vascular complications (0.6% vs. 1.7%; OR: 0.32; 95% CI: 0.12 to 0.90). Access site crossover was significantly higher among women assigned to radial access (PCI cohort: 6.1% vs. 1.7%; OR: 3.65; 95% CI: 1.45 to 9.17); total randomized cohort: (6.7% vs. 1.9%; OR: 3.70; 95% CI: 2.14 to 6.40). More women preferred radial access. In this pragmatic trial, which was terminated early, the radial approach did not significantly reduce bleeding or vascular complications in women undergoing PCI. Access site crossover occurred more often in women assigned to radial access. (SAFE-PCI for Women; NCT01406236). Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc

  10. Influences on achieving motor milestones: A twin-singleton study

    NARCIS (Netherlands)

    Brouwer, S.I.; van Beijsterveldt, C.E.M.; Bartels, M.; Hudziak, J.; Boomsma, D.I.

    2006-01-01

    In order to determine if twinning impacted achievement of motor milestones the attainment of early motor milestones in twins was examined and compared to published data from singletons of the same age from the same culture and birth years. We examined the influence of twinning, sex, zygosity and

  11. Twin study on transplacental-acquired antibodies and attention deficit/hyperactivity disorder - A pilot study

    DEFF Research Database (Denmark)

    Bilenberg, Niels; Hougaard, David; Norgaard-Pedersen, Bent

    2011-01-01

    OBJECTIVE: We hypothesize that maternal transplacentally acquired antibodies may cause Attention Deficit/Hyperactivity Disorder (ADHD) symptoms years after birth, and tested the hypothesis in twins discordant for ADHD symptoms. METHOD: In a pre-screened sample of 7793 same sex twin pair's (4......-18years) questionnaire data on hyperactivity and inattention was collected. Blood samples taken 5days after birth from 190 ADHD-score discordant pairs (15% MZ) were analyzed for antibodies. RESULTS: Pneumococcus Polysaccaride 14 (PnPs14) was present in the ADHD high scoring twin more often than...... in the lower scoring twin (P=0.04). CONCLUSION: Although the study provides no strong support for the hypothesis, infection or immunological factors may be one among several causes of ADHD. The genetic control obtained in a twin design may reduce the exposure contrast and a larger sample is needed to further...

  12. A TWIN STUDY OF SCHIZOAFFECTIVE-MANIA, SCHIZOAFFECTIVE-DEPRESSION AND OTHER PSYCHOTIC SYNDROMES

    OpenAIRE

    Cardno, Alastair G; Rijsdijk, Frühling V; West, Robert M; Gottesman, Irving I; Craddock, Nick; Murray, Robin M; McGuffin, Peter

    2011-01-01

    The nosological status of schizoaffective disorders remains controversial. Twin studies are potentially valuable for investigating relationships between schizoaffective-mania, schizoaffective-depression and other psychotic syndromes, but no such study has yet been reported. We ascertained 224 probandwise twin pairs (106 monozygotic, 118 same-sex dizygotic), where probands had psychotic or manic symptoms, from the Maudsley Twin Register in London (1948–1993). We investigated Research Diagnosti...

  13. Prognostic and survival analysis of presbyopia: The healthy twin study

    Science.gov (United States)

    Lira, Adiyani; Sung, Joohon

    2015-12-01

    Presbyopia, a vision condition in which the eye loses its flexibility to focus on near objects, is part of ageing process which mostly perceptible in the early or mid 40s. It is well known that age is its major risk factor, while sex, alcohol, poor nutrition, ocular and systemic diseases are known as common risk factors. However, many other variables might influence the prognosis. Therefore in this paper we developed a prognostic model to estimate survival from presbyopia. 1645 participants which part of the Healthy Twin Study, a prospective cohort study that has recruited Korean adult twins and their family members based on a nation-wide registry at public health agencies since 2005, were collected and analyzed by univariate analysis as well as Cox proportional hazard model to reveal the prognostic factors for presbyopia while survival curves were calculated by Kaplan-Meier method. Besides age, sex, diabetes, and myopia; the proposed model shows that education level (especially engineering program) also contribute to the occurrence of presbyopia as well. Generally, at 47 years old, the chance of getting presbyopia becomes higher with the survival probability is less than 50%. Furthermore, our study shows that by stratifying the survival curve, MZ has shorter survival with average onset time about 45.8 compare to DZ and siblings with 47.5 years old. By providing factors that have more effects and mainly associate with presbyopia, we expect that we could help to design an intervention to control or delay its onset time.

  14. Association of Depressive Symptoms and Heart Rate Variability in Vietnam War-Era Twins: A Longitudinal Twin Difference Study.

    Science.gov (United States)

    Huang, Minxuan; Shah, Amit; Su, Shaoyong; Goldberg, Jack; Lampert, Rachel J; Levantsevych, Oleksiy M; Shallenberger, Lucy; Pimple, Pratik; Bremner, J Douglas; Vaccarino, Viola

    2018-05-16

    Depressive symptoms are associated with lower heart rate variability (HRV), an index of autonomic dysregulation, but the direction of the association remains unclear. To investigate the temporal association between depression and HRV. A longitudinal, cross-lagged twin difference study, with baseline assessments from March 2002 to March 2006 (visit 1) and a 7-year follow-up (visit 2) at an academic research center with participants recruited from a national twin registry. Twins (n = 166) from the Vietnam Era Twin Registry, who served in the US military during the Vietnam War, and were discordant for depression at baseline were recruited. At both visits, depressive symptoms were measured using the Beck Depression Inventory-II (BDI-II), and HRV was measured through 24-hour electrocardiogram monitoring. To assess the direction of the association, within-pair differences in multivariable mixed-effects regression models were examined, and standardized β coefficients for both pathways were calculated. The associations were evaluated separately in monozygotic and dizygotic twins. In the final analytic sample (N = 146), all participants were men, 138 (95%) were white, and the mean (SD) age was 54 (3) years at baseline. Results showed consistent associations between visit 1 HRV and visit 2 BDI score across all HRV domains and models (β coefficients ranging from -0.14 to -0.29), which were not explained by antidepressants or other participant characteristics. The magnitude of the association was similar in the opposite pathway linking visit 1 BDI score to visit 2 HRV, with β coefficients ranging from 0.05 to -0.30, but it was largely explained by antidepressant use. In stratified analysis by zygosity, significant associations were observed in monozygotic and dizygotic twins for the path linking visit 1 HRV to visit 2 BDI score, although the associations were slightly stronger in dizygotic twins. The association between depression and autonomic dysregulation

  15. A twin study of the neuropsychological consequences of stimulant abuse.

    Science.gov (United States)

    Toomey, Rosemary; Lyons, Michael J; Eisen, Seth A; Xian, Hong; Chantarujikapong, Sunanta; Seidman, Larry J; Faraone, Stephen V; Tsuang, Ming T

    2003-03-01

    Previous studies document neuropsychological deficits associated with stimulant abuse, but findings are inconsistent. We identified 50 twin pairs in which only 1 member had heavy stimulant abuse (cocaine and/or amphetamines) ending at least 1 year before the evaluation. The co-twin control research design controls for familial vulnerability and makes it easier to identify neuropsychological deficits that are consequences of stimulant abuse. Subjects were administered an extensive neuropsychological test battery organized into the following 5 functions: attention, executive functioning, motor skills, intelligence, and memory. Multivariate tests showed that abusers performed significantly worse than nonabusers on functions of attention and motor skills. Within each of these functions, univariate tests showed that abusers performed significantly worse on certain tests of motor skills and attention. In contrast, abusers performed significantly better on one test of attention measuring visual vigilance. Within the abuser group, higher levels of stimulant use were largely uncorrelated with neuropsychological test scores, although a few significant correlations indicated better functioning with more stimulant use. With ideal controls, this study demonstrates that deficits in attention and motor skills persist after 1 year of abstinence from stimulant use and raises hypotheses regarding relative strengths on a vigilance task among abusers.

  16. A longitudinal twin study of the association between childhood autistic traits and psychotic experiences in adolescence

    OpenAIRE

    Taylor, Mark J.; Robinson, Elise B.; Happ?, Francesca; Bolton, Patrick; Freeman, Daniel; Ronald, Angelica

    2015-01-01

    Background: This twin study investigated whether autistic traits during childhood were associated with adolescent psychotic experiences. Methods: Data were collected from a community sample of approximately 5000 twin pairs, which included 32 individuals with diagnosed autism spectrum conditions (ASC). Parents rated autistic traits in the twins at four points between ages 8–16 years. Positive, negative, and cognitive psychotic experiences were assessed at age 16 years using self- and parent-re...

  17. Tuning the thermal conductivity of silicon carbide by twin boundary: a molecular dynamics study

    International Nuclear Information System (INIS)

    Liu, Qunfeng; Wang, Liang; Shen, Shengping; Luo, Hao

    2017-01-01

    Silicon carbide (SiC) is a semiconductor with excellent mechanical and physical properties. We study the thermal transport in SiC by using non-equilibrium molecular dynamics simulations. The work is focused on the effects of twin boundaries and temperature on the thermal conductivity of 3C-SiC. We find that compared to perfect SiC, twinned SiC has a markedly reduced thermal conductivity when the twin boundary spacing is less than 100 nm. The Si–Si twin boundary is more effective to phonon scattering than the C–C twin boundary. We also find that the phonon scattering effect of twin boundary decreases with increasing temperature. Our findings provide insights into the thermal management of SiC-based electronic devices and thermoelectric applications. (paper)

  18. Atomistic simulation study of deformation twinning of nanocrystalline body-centered cubic Mo

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Xiaofeng [The College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu (China); Li, Dan, E-mail: txf8378@163.com [The College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu (China); Yu, You [College of Optoelectronic Technology, Chengdu University of Information Technology, Chengdu (China); You, Zhen Jiang [Australian School of Petroleum, University of Adelaide, SA 5005 (Australia); Li, Tongye [The National Key Laboratory of Nuclear Fuel and Materials, Nuclear Power Institute of China, Chengdu (China); Ge, Liangquan [The College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu (China)

    2017-04-06

    Deformation twinning of nanocrystalline body-centered cubic Mo was studied using molecular dynamics simulations, and the effects of grain sizes and temperatures on the deformation were evaluated. With small grain size, grain rotation accompanying grain growth was found to play important role in nanocrystalline Mo during tensile deformation. Additionally, grain rotation and the deformation controlled by GB-mediated processes induce to the difficulty of creating crack. Twin was formed by successive emission of twinning partials from grain boundaries in small grain size systems. However, the twin mechanisms of GB splitting and overlapping of two extended dislocations were also found in larger size grain. Twin induced crack tips were observed in our simulation, and this confirmed the results of previous molecular dynamics simulations. At higher temperatures, GB activities can be thermally activated, resulting in suppression of twinning tendency and improvement of ductility of nanocrystalline Mo.

  19. Motor Development and Physical Activity: A Longitudinal Discordant Twin-Pair Study.

    Science.gov (United States)

    Aaltonen, Sari; Latvala, Antti; Rose, Richard J; Pulkkinen, Lea; Kujala, Urho M; Kaprio, Jaakko; Silventoinen, Karri

    2015-10-01

    Previous longitudinal research suggests that motor proficiency in early life predicts physical activity in adulthood. Familial effects including genetic and environmental factors could explain the association, but no long-term follow-up studies have taken into account potential confounding by genetic and social family background. The present twin study investigated whether childhood motor skill development is associated with leisure-time physical activity levels in adulthood independent of family background. Altogether, 1550 twin pairs from the FinnTwin12 study and 1752 twin pairs from the FinnTwin16 study were included in the analysis. Childhood motor development was assessed by the parents' report of whether one of the co-twins had been ahead of the other in different indicators of motor skill development in childhood. Leisure-time physical activity (MET·h·d) was self-reported by the twins in young adulthood and adulthood. Statistical analyses included conditional and ordinary linear regression models within twin pairs. Using all activity-discordant twin pairs, the within-pair difference in a sum score of motor development in childhood predicted the within-pair difference in the leisure-time physical activity level in young adulthood (P men and women.

  20. A twin-family study of general IQ

    NARCIS (Netherlands)

    Leeuwen, M; van den Berg, Stéphanie Martine; Boomsma, D.I.

    2008-01-01

    In this paper we assess the presence of assortative mating, gene¿environment interaction and the heritability of intelligence in childhood usinga twin family design with twins, their siblings and parents from 112 families. We evaluate two competing hypotheses about the cause of assortativemating in

  1. A twin-family study of general IQ.

    NARCIS (Netherlands)

    van Leeuwen, M.; van den Berg, S.M.; Boomsma, D.I.

    2008-01-01

    In this paper we assess the presence of assortative mating, gene-environment interaction and the heritability of intelligence in childhood using a twin family design with twins, their siblings and parents from 112 families. We evaluate two competing hypotheses about the cause of assortative mating

  2. The Prenatal Environment in Twin Studies: A Review on Chorionicity

    NARCIS (Netherlands)

    Marceau, K.; McMaster, M.T.; Smith, T.F.; Daams, J.G.; van Beijsterveldt, C.E.M.; Boomsma, D.I.; Knopik, V.S.

    2016-01-01

    A literature search was conducted to identify articles examining the association of chorionicity (e.g., whether twins share a single chorion and thus placenta or have separate chorions/placentas) and genetics, psychiatry/behavior, and neurological manifestations in humans twins and higher-order

  3. STUDY OF MATERNAL AND FOETAL OUTCOME IN TWIN PREGNANCY

    Directory of Open Access Journals (Sweden)

    Burri Sandhya Rani

    2018-01-01

    Full Text Available BACKGROUND In comparison to singleton pregnancies, twin pregnancies are considered a high risk pregnancies associated with perinatal mortalities and maternal morbidities due to unnecessary use of ovulation induced drugs. The aim of the study is to evaluate the maternal and foetal outcomes in twin gestations and to find the various factors that contribute to adverse perinatal outcome. MATERIALS AND METHODS This study was carried out in Laxmi Narasimha Hospital, Warangal, Hanamkonda, Telangana, an over a period of May 2015 to August 2016. RESULTS Most of the women were in their fertile age i.e. in between 20-30 years of age (86.6%. In both primigravida and multigravidas, the twins were equal. Preterm labour complications were seen in 88.8% of the patients and PIH was seen in 11.2% of the patients. Anaemia was the most common mal-presentation seen in the patients which constituted to 33.3%. Number of patients who underwent mode of delivery through spontaneous vaginal section were 60 which constituted 66.7%, caesarean section were 25 which constituted 27.7%, instrumental vaginal section were 5 which constituted 5.6%. The number of patients who had the foetal birth weight 2000 grams were 55 which constituted 30.6%. The number of male babies were 110 (61.1% and female babies were 70 (38.9%. Number of live births were 170 (94.4%, still births were 10 (5.6%. Number of patients admitted in ICU were 100 (55.6%, Neonatal morbidity was seen in 38 patients (21.1%, neonatal mortality was seen in 10 patients (5.6%. The most common cause of neonatal death was septicaemia followed by respiratory distress, pulmonary distress and DIC. CONCLUSION This study concluded that deaths were majorly due to extremely premature and very low birth weight babies. These babies had septicaemia or respiratory distress. By averting pre-term births, by taking good rest, cervical encerclage, when incompetence is suspected, short term tocolysis, prevention of anaemia and pre

  4. Genetics of dietary habits and obesity - a twin study

    DEFF Research Database (Denmark)

    Hasselbalch, Ann Louise

    2010-01-01

    residual genetic influence existed. Based on information about habitual diet from the FFQ the genetic influence on total energy intake, macronutrient intake, as well as intake of energy from 20 food groups, was estimated. The proportion of variation in dietary intake explained by variation in genes...... exposures as well as genetic differences between individuals, resulting in differentiated susceptibility to environmental exposures. The evidence for genetic influence on anthropometry has previously been established and has been estimated to be 60-70% based on twin studies. These inter...... mass, but only limited evidence for associations between habitual dietary intake and anthropometry exists. Differences in habitual dietary intake are also partly determined by differences in genes influencing smell and taste preferences. But, so far, only few studies have investigated genetic...

  5. Twinning in Iranian Holstein Dairy Cattle: A Study of Risk Factors and Production and Reproduction Consequences

    Directory of Open Access Journals (Sweden)

    abolfazl mahnani

    2016-08-01

    Full Text Available Introduction Cattle are a monotocous species meaning that, under most circumstances, a successful pregnancy results in the birth of one calf. Twinning rate has been reported in dairy cows from 3 to 5 percent, which can be influenced by maternal age.The birth of twins is detrimental to the majority of beef and dairy cattle producer. Financial loss arising from any of twinning has been reported in Europe between 109 to 201 dollars in recent years. Because it is associated with undesirable consequences such as reduced survival, calf, cow increased removal rate and poor performance. This also reduces pregnancy rates and profitability herds. One of the effects of twinning severe is reduction of the number of calves for replacement fertility in dairy cows. This is a loss arising from an increase in infant mortality and a gender bias in bull calves homo zygote.Twinning rate increases significantly the incidence of reproductive abnormalities, including the retained placenta, dystocia, stillbirth and abortion. Many studies have been done on the effect of multiple pregnancies in cattle production and reproduction. Higher milk production for cows twin issue is controversial as some studies have shown that there is a positive correlation between the rate of twinning in dairy cattle and milk production. But in the next lactation, production for cows that have been the twin of the infected cow metabolic disease in the previous period was lower. In a study reported that cows spend fewer days in the twin peak production. The results of the study on the effect of twinning on reproductive traits of Holstein cows-Farzin showed that only half of the twin cows are prone to reproduce in the next period. It is also reported a greater number of insemination per conception in twin compared to single cows. In addition, it has been reported that the twin was more than 15 days from calving to first services. Average twin cows experiencing 1.7 times more death and removal

  6. Does the sex of one's co-twin affect height and BMI in adulthood? A study of dizygotic adult twins from 31 cohorts.

    Science.gov (United States)

    Bogl, Leonie H; Jelenkovic, Aline; Vuoksimaa, Eero; Ahrenfeldt, Linda; Pietiläinen, Kirsi H; Stazi, Maria A; Fagnani, Corrado; D'Ippolito, Cristina; Hur, Yoon-Mi; Jeong, Hoe-Uk; Silberg, Judy L; Eaves, Lindon J; Maes, Hermine H; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Cutler, Tessa L; Kandler, Christian; Jang, Kerry L; Christensen, Kaare; Skytthe, Axel; Kyvik, Kirsten O; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; Derom, Catherine A; Vlietinck, Robert F; Nelson, Tracy L; Whitfield, Keith E; Corley, Robin P; Huibregtse, Brooke M; McAdams, Tom A; Eley, Thalia C; Gregory, Alice M; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Willemsen, Gonneke; Bartels, Meike; van Beijsterveldt, Toos C E M; Pang, Zengchang; Tan, Qihua; Zhang, Dongfeng; Martin, Nicholas G; Medland, Sarah E; Montgomery, Grant W; Hjelmborg, Jacob V B; Rebato, Esther; Swan, Gary E; Krasnow, Ruth; Busjahn, Andreas; Lichtenstein, Paul; Öncel, Sevgi Y; Aliev, Fazil; Baker, Laura A; Tuvblad, Catherine; Siribaddana, Sisira H; Hotopf, Matthew; Sumathipala, Athula; Rijsdijk, Fruhling; Magnusson, Patrik K E; Pedersen, Nancy L; Aslan, Anna K Dahl; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Duncan, Glen E; Buchwald, Dedra; Tarnoki, Adam D; Tarnoki, David L; Yokoyama, Yoshie; Hopper, John L; Loos, Ruth J F; Boomsma, Dorret I; Sørensen, Thorkild I A; Silventoinen, Karri; Kaprio, Jaakko

    2017-01-01

    The comparison of traits in twins from opposite-sex (OS) and same-sex (SS) dizygotic twin pairs is considered a proxy measure of prenatal hormone exposure. To examine possible prenatal hormonal influences on anthropometric traits, we compared mean height, body mass index (BMI), and the prevalence of being overweight or obese between men and women from OS and SS dizygotic twin pairs. The data were derived from the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) database, and included 68,494 SS and 53,808 OS dizygotic twin individuals above the age of 20 years from 31 twin cohorts representing 19 countries. Zygosity was determined by questionnaires or DNA genotyping depending on the study. Multiple regression and logistic regression models adjusted for cohort, age, and birth year with the twin type as a predictor were carried out to compare height and BMI in twins from OS pairs with those from SS pairs and to calculate the adjusted odds ratios and 95% confidence intervals for being overweight or obese. OS females were, on average, 0.31 cm (95% confidence interval (CI) 0.20, 0.41) taller than SS females. OS males were also, on average, taller than SS males, but this difference was only 0.14 cm (95% CI 0.02, 0.27). Mean BMI and the prevalence of overweight or obesity did not differ between males and females from SS and OS twin pairs. The statistically significant differences between OS and SS twins for height were small and appeared to reflect our large sample size rather than meaningful differences of public health relevance. We found no evidence to support the hypothesis that prenatal hormonal exposure or postnatal socialization (i.e., having grown up with a twin of the opposite sex) has a major impact on height and BMI in adulthood.

  7. Genetic and Environmental Effects on Stuttering: A Twin Study from Finland

    Science.gov (United States)

    Rautakoski, Pirkko; Hannus, Therese; Simberg, Susanna; Sandnabba, N. Kenneth; Santtila, Pekka

    2012-01-01

    The present study explored the prevalence of self-reported stuttering in a Finnish twin population and examined the extent to which the variance in liability to stuttering was attributable to genetic and environmental effects. We analyzed data of 1728 Finnish twins, born between 1961 and 1989. The participants were asked to complete a…

  8. The Netherlands twin register biobank: A resource for genetic epidemiological studies

    NARCIS (Netherlands)

    Willemsen, G.; Geus, E.J.C. de; Bartels, M.; Beijsterveldt, C.E.M.T. van; Brooks, A.I.; Estourgie-van Burk, G.F.; Fugman, D.A.; Hoekstra, C.; Hottenga, J.-J.; Kluft, K.; Meijer, P.; Montgomery, G.W.; Rizzu, P.; Sondervan, D.; Smit, A.B.; Spijker, S.; Suchiman, H.E.D.; Tischfield, J.A.; Lehner, T.; Slagboom, P.E.; Boomsma, D.I.

    2010-01-01

    In 2004 the Netherlands Twin Register (NTR) started a large scale biological sample collection in twin families to create a resource for genetic studies on health, lifestyle and personality. Between January 2004 and July 2008, adult participants from NTR research projects were invited into the

  9. The etiology of autistic traits in preschoolers : a population-based twin study

    NARCIS (Netherlands)

    de Zeeuw, E.L.; van Beijsterveldt, Catharina E M; Hoekstra, Rosa A; Bartels, Meike; Boomsma, Dorret I

    2017-01-01

    BACKGROUND: Autism Spectrum Disorders (ASD) are highly heritable, but the exact etiological mechanisms underlying the condition are still unclear. METHODS: Using a multiple rater twin design in a large sample of general population preschool twins, this study aimed to (a) estimate the contribution of

  10. Has the "Equal Environments" assumption been tested in twin studies?

    Science.gov (United States)

    Eaves, Lindon; Foley, Debra; Silberg, Judy

    2003-12-01

    A recurring criticism of the twin method for quantifying genetic and environmental components of human differences is the necessity of the so-called "equal environments assumption" (EEA) (i.e., that monozygotic and dizygotic twins experience equally correlated environments). It has been proposed to test the EEA by stratifying twin correlations by indices of the amount of shared environment. However, relevant environments may also be influenced by genetic differences. We present a model for the role of genetic factors in niche selection by twins that may account for variation in indices of the shared twin environment (e.g., contact between members of twin pairs). Simulations reveal that stratification of twin correlations by amount of contact can yield spurious evidence of large shared environmental effects in some strata and even give false indications of genotype x environment interaction. The stratification approach to testing the equal environments assumption may be misleading and the results of such tests may actually be consistent with a simpler theory of the role of genetic factors in niche selection.

  11. A lateral cephalometric study of craniofacial variation in Korean child twins

    International Nuclear Information System (INIS)

    Lee, Sang Rae; You, Dong Soo

    1974-01-01

    A study was performed to investigate the degree of similarities and differences in components of craniofacial complex between Korean twins and normal children by lateral cephalometric analysis. Dimensions of S-N, S-Ba, N-Ba, Go-Me, Ar-Go and Ar-Me were plotted against linear measurement and angles of N-S-Ba and gonial against angular measurement in twins and control groups. The lateral cephalograms of twin were composed of 88 twins aged from 7 to 12:44 males aged 10.65 and 44 females aged 9. 55, while those of 50 normalities were composed of 25 male and 25 female aged 10.9 respectively. In order to analyze growth proportion and sexual differences, twins were divided into 3 groups according to two year age intervals and the author compared male with female in 3 groups. For the purpose of observing similarities and differences in twins and normalities by sex, total twins were compared with normalities. The obtained results were as follows: 1. There was no difference in craniofacial complex between twins and normalities. 2. In general, the measurements of male were larger than those of female in both twins and normalities, but there were no statistical significances of sexual differences in both groups. 3. The growth proportion of mandible by aging was larger than that of face in twins. 4. The growth pattern of gonial angle showed slight reducing tendency in twin by aging. 5. There was little difference in the growth proportion of both male and female.

  12. A lateral cephalometric study of craniofacial variation in Korean child twins

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Rae; You, Dong Soo [College of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    1974-11-15

    A study was performed to investigate the degree of similarities and differences in components of craniofacial complex between Korean twins and normal children by lateral cephalometric analysis. Dimensions of S-N, S-Ba, N-Ba, Go-Me, Ar-Go and Ar-Me were plotted against linear measurement and angles of N-S-Ba and gonial against angular measurement in twins and control groups. The lateral cephalograms of twin were composed of 88 twins aged from 7 to 12:44 males aged 10.65 and 44 females aged 9. 55, while those of 50 normalities were composed of 25 male and 25 female aged 10.9 respectively. In order to analyze growth proportion and sexual differences, twins were divided into 3 groups according to two year age intervals and the author compared male with female in 3 groups. For the purpose of observing similarities and differences in twins and normalities by sex, total twins were compared with normalities. The obtained results were as follows: 1. There was no difference in craniofacial complex between twins and normalities. 2. In general, the measurements of male were larger than those of female in both twins and normalities, but there were no statistical significances of sexual differences in both groups. 3. The growth proportion of mandible by aging was larger than that of face in twins. 4. The growth pattern of gonial angle showed slight reducing tendency in twin by aging. 5. There was little difference in the growth proportion of both male and female.

  13. Ethical aspects of registry-based research in the Nordic countries

    Directory of Open Access Journals (Sweden)

    Ludvigsson JF

    2015-11-01

    Full Text Available Jonas F Ludvigsson,1,2 Siri E Håberg,3 Gun Peggy Knudsen,3 Pierre Lafolie,4,5 Helga Zoega,6 Catharina Sarkkola,7 Stephanie von Kraemer,7 Elisabete Weiderpass,1,7–10 Mette Nørgaard11 1Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, 2Department of Pediatrics, Örebro University Hospital, Örebro, Sweden; 3Norwegian Institute of Public Health, Oslo, Norway; 4Department of Medicine, Clinical Pharmacology Unit, 5The Stockholm Regional Ethical Review Board, Karolinska Institutet, Stockholm, Sweden; 6Center of Public Health Sciences, Faculty of Medicine, University of Iceland, Reykjavík, Iceland; 7Genetic Epidemiology Group, Folkhälsan Research Center, Helsinki, Finland; 8Department of Community Medicine, Faculty of Health Sciences, University of Tromsø, 9The Arctic University of Norway, Tromsø, 10Department of Research, Cancer Registry of Norway, Oslo, Norway; 11Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark Abstract: National health care registries in the Nordic countries share many attributes, but different legal and ethical frameworks represent a challenge to promoting effective joint research. Internationally, there is a lack of knowledge about how ethical matters are considered in Nordic registry-based research, and a lack of knowledge about how Nordic ethics committees operate and what is needed to obtain an approval. In this paper, we review ethical aspects of registry-based research, the legal framework, the role of ethics review boards in the Nordic countries, and the structure of the ethics application. We discuss the role of informed consent in registry-based research and how to safeguard the integrity of study participants, including vulnerable subjects and children. Our review also provides information on the different government agencies that contribute registry-based data, and a list of the major health registries in Denmark, Finland, Iceland, Norway, and

  14. Estimating heritability for cause specific mortality based on twin studies

    DEFF Research Database (Denmark)

    Scheike, Thomas; Holst, Klaus Kähler; von Bornemann Hjelmborg, Jacob

    2014-01-01

    the Danish twin registry and discuss how to define heritability for cancer occurrence. The key point is that this should be done taking censoring as well as competing risks due to e.g.  death into account. We describe the dependence between twins on the probability scale and show that various models can...... be used to achieve sensible estimates of the dependence within monozygotic and dizygotic twin pairs that may vary over time. These dependence measures can subsequently be decomposed into a genetic and environmental component using random effects models. We here present several novel models that in essence...

  15. Heritability of retinal vascular fractals: a twin study

    DEFF Research Database (Denmark)

    Vergmann, Anna Stage; Broe, Rebecca; Kessel, Line

    . The retinal vascular fractal dimension was measured using the box-counting method and compared within monozygotic and dizygotic twin pairs using Pearson correlation coefficents. Falconer´s formula and quantitative genetic models were used to determine the genetic component of variation. Results: The retinal...... for quantitative analysis of heritability. The intrapair correlation was markedly higher (0.505, p=0.0002) in monozygotic twins than in dizygotic twins (0.108, p=0.46), corresponding to a heritability h2 for the fractal dimension of 0.79. In quantitative genetic models, 54% of the variation was explained...

  16. Genetic influences on musical specialization: a twin study on choice of instrument and music genre.

    Science.gov (United States)

    Mosing, Miriam A; Ullén, Fredrik

    2018-05-09

    Though several studies show that genetic factors influence individual differences in musical engagement, aptitude, and achievement, no study to date has investigated whether specialization among musically active individuals in terms of choice of instrument and genre is heritable. Using a large twin cohort, we explored whether individual differences in instrument choice, instrument category, and the type of music individuals engage in can entirely be explained by the environment or are partly due to genetic influences. About 10,000 Swedish twins answered an extensive questionnaire about music-related traits, including information on the instrument and genre they played. Of those, 1259 same-sex twin pairs reported to either play an instrument or sing. We calculated the odds ratios (ORs) for concordance in music choices (if both twins played) comparing identical and nonidentical twin pairs, with significant ORs indicating that identical twins are more likely to engage in the same type of music-related behavior than are nonidentical twins. The results showed that for almost all music-related variables, the odds were significantly higher for identical twins to play the same musical instrument or music genre, suggesting significant genetic influences on such music specialization. Possible interpretations and implications of the findings are discussed. © 2018 New York Academy of Sciences.

  17. Twin studies as a model for exploring the aetiology of autoimmune thyroid disease

    DEFF Research Database (Denmark)

    Brix, Thomas Heiberg; Hegedüs, Laszlo

    2012-01-01

    Twins are an important resource for evaluating the relative contribution of genetic and environmental factors in determining a phenotype. During the last decades, a number of twin studies have investigated the aetiology of several phenotypes related to thyroid autoimmunity. Taken together, these ....... Future twin studies should incorporate information on genetic, epigenetic and environmental variation thereby enhancing our ability to quantify the precise effect of specific risk factors......., and biometric twin modelling shows that approximately 75% of the total phenotypic variance in AITD is because of genetic effects. On the other hand, the lack of complete concordance in MZ twin pairs is proof of environmental and/or epigenetic factors also playing an important role. The impact of environmental...

  18. Analysis of 1:1 Matched Cohort Studies and Twin Studies, with Binary Exposures and Binary Outcomes

    OpenAIRE

    Sjölander, Arvid; Johansson, Anna L. V.; Lundholm, Cecilia; Altman, Daniel; Almqvist, Catarina; Pawitan, Yudi

    2012-01-01

    To improve confounder adjustments, observational studies are often matched on potential confounders. While matched case-control studies are common and well covered in the literature, our focus here is on matched cohort studies, which are less common and sparsely discussed in the literature. Matched data also arise naturally in twin studies, as a cohort of exposure–discordant twins can be viewed as being matched on a large number of potential confounders. The analysis of twin studies will be g...

  19. Risk factors for testicular cancer: a case-control study in twins.

    Science.gov (United States)

    Swerdlow, A J; De Stavola, B L; Swanwick, M A; Mangtani, P; Maconochie, N E

    1999-06-01

    Early life and anthropometric risk factors for testicular cancer were examined in a case-control study in England and Wales in which affected male twins were compared with their unaffected male co-twins. Questionnaire data was obtained for 60 twin pairs. Significantly raised risk of testicular cancer occurred in twins who had longer arms and legs than their co-twin. There was a significant excess of testicular cancer reported in non-twin brothers, as well as in twin brothers, of cases. Risk was also significantly raised in relation to cryptorchidism. The results on limb length suggest that factors, perhaps nutritional, affecting growth before puberty, may be causes of testicular cancer. The results on risk in brothers add to evidence of a large genetic component in aetiology of the tumour. The risk associated with cryptorchidism in the twins accords with the hypothesis that cryptorchidism is causally associated with testicular cancer because it is a cause of the malignancy, rather than because the same maternal factors experienced in utero cause both conditions.

  20. Evidence of genetic susceptibility to infectious mononucleosis: a twin study.

    Science.gov (United States)

    Hwang, A E; Hamilton, A S; Cockburn, M G; Ambinder, R; Zadnick, J; Brown, E E; Mack, T M; Cozen, W

    2012-11-01

    Infectious mononucleosis is a clinical manifestation of primary Epstein-Barr virus infection. It is unknown whether genetic factors contribute to risk. To assess heritability, we compared disease concordance in monozygotic to dizygotic twin pairs from the population-based California Twin Program and assessed the risk to initially unaffected co-twins. One member of 611 and both members of 58 twin pairs reported a history of infectious mononucleosis. Pairwise concordance in monozygotic and dizygotic pairs was respectively 12·1% [standard error (s.e.)=1·9%] and 6·1% (s.e.=1·2%). The relative risk (hazard ratio) of monozygotic compared to dizygotic unaffected co-twins of cases was 1·9 [95% confidence interval (CI) 1·1-3·4, P=0·03], over the follow-up period. When the analysis was restricted to same-sex twin pairs, that estimate was 2·5 (95% CI 1·2-5·3, P=0·02). The results are compatible with a heritable contribution to the risk of infectious mononucleosis.

  1. Art for twins: Yorùbá artists and their statues/twin research studies: twins' education and conceptions; diurnal preference; inherited eye diseases; ultrasound counseling when twins are conjoined/popular twin reports: twin sisters (the film); rare pregnancy; diet test; French twins reared apart and reunited.

    Science.gov (United States)

    Segal, Nancy L

    2014-06-01

    The Yorùbá of Nigeria are well known for their high twinning rate and the statues they create to commemorate deceased twins. An impressive collection of this artwork was displayed at the University of California's Fowler Museum in Los Angeles between October 13, 2013 and March 2, 2014. An overview of this exhibit is provided. Next, twin research on maternal education and conception, diurnal preference, inherited eye diseases, and ultrasound counseling for couples with conjoined twins are briefly summarized. This article concludes with a discussion of media-based items related to twins. The topics include an award-winning twin film, a rare pregnancy, a diet test, and the separation and chance reunion of monozygotic female twins.

  2. A synthetic medical and sociological study on twins exposed by atomic bomb, 8

    International Nuclear Information System (INIS)

    Satow, Yukio; Watanabe, Shoji; Kyo, Taiichi

    1984-01-01

    The relationship between immunoglobulin (IgG, IgA, IgM) levels and the exposure status was examined in 13 enzygotic twin pairs who had been exposed to atomic bomb under the same or different conditions and who had no disease showing changes in immunoglobulin levels. The difference in immunoglobulin levels tended to be smaller between the twins exposed under the same conditions and to be larger between the twins exposed under the different conditions. This should be further studied because there were some exceptions in this study. (Namekawa, K.)

  3. Bruxism Is Associated With Nicotine Dependence: A Nationwide Finnish Twin Cohort Study

    Science.gov (United States)

    Ahlberg, J.; Hublin, C.; Broms, U.; Madden, P. A. F.; Könönen, M.; Koskenvuo, M.; Lobbezoo, F.; Kaprio, J.

    2010-01-01

    Objectives: To investigate the association of smoking with bruxism while controlling for genetic and environmental factors using a co-twin-control design. Especially, the role of nicotine dependence was studied in this context. Methods: The material derives from the Finnish Twin Cohort consisting of 12,502 twin individuals who responded to a questionnaire in 1990 (response rate of 77%). All were born in 1930–1957, the mean age being 44 years. The questionnaire covered 103 multiple choice questions, 7 dealing with tobacco use and 22 with sleep and vigilance matters, including perceived bruxism. In addition, a subsample derived from the Nicotine Addiction Genetics Finland Study containing 445 twin individuals was studied. Results: In age- and gender-controlled multinomial logistic regression, both monthly and rarely reported bruxism associated with both current cigarette smoking (odds ratio [OR] = 1.74 and 1.64) and former cigarette smoking (OR = 1.64 and 1.47). Weekly bruxism associated with current smoking (OR = 2.85). Current smokers smoking 20 or more cigarettes a day reported weekly bruxism more likely (OR = 1.61–1.97) than those smoking less. Among twin pairs (N = 142) in which one twin was a weekly bruxer and the cotwin a never bruxer, there were 13 monozygotic pairs in which one twin was a current smoker and the other twin was not. In all cases, the bruxer was the smoker (p = .0003). Nicotine dependence associated significantly with bruxism. Conclusions: Our twin study provides novel evidence for a possible causal link between tobacco use and bruxism among middle-aged adults. Nicotine dependence may be a significant predisposing factor for bruxism. PMID:21041838

  4. Anorexia and Bulimia Nervosa in Same-Sex and Opposite-Sex Twins : Lack of Association With Twin Type in a Nationwide Study of Finnish Twins

    NARCIS (Netherlands)

    Raevuori, Anu; Kaprio, Jaakko; Hoek, Hans W.; Sihvola, Elina; Rissanen, Aila; Keski-Rahkonen, Anna

    2008-01-01

    Objective: The authors tested the hypothesis that either prenatal feminization or masculinization hormone influences in utero or later socialization affects the risk for anorexia and bulimia nervosa and disordered eating in members of opposite-sex twin pairs. Method: Finnish twins (N=2,426 women,

  5. The genetic and environmental influences on childhood obesity: a systematic review of twin and adoption studies

    DEFF Research Database (Denmark)

    Silventoinen, K; Rokholm, B; Kaprio, J

    2010-01-01

    In this systematic review, we aimed to collect together all previous twin and adoption studies on childhood and adolescent obesity up to the age of 18 years. Using several sources, we identified nine twin and five adoption studies; all of these studies had used relative weight as an indicator...... a substantial effect in mid-childhood, but this effect disappeared at adolescence. Adoption studies supported the role of family environment in childhood obesity as correlations were found between adoptees and adoptive parents; however, correlations were substantially stronger between parents...... of obesity. Except the two twin studies from the Korean population, all studies represented Caucasian populations. In a meta-analysis of these twin studies, we found that genetic factors had a strong effect on the variation of body mass index (BMI) at all ages. The common environmental factors showed...

  6. Experimental and Numerical Study of Twin Underexpanded Impinging Jets

    Institute of Scientific and Technical Information of China (English)

    Minoru Yaga; Minoru Okano; Masumi Tamashiro; Kenyu Oyakawa

    2003-01-01

    In this paper, the dual underexpanded impinging jets are experimentally and numerically studied. The experiments were performed by measuring the unsteady and averaged wall static pressures and by visualizing density fields using schlieren method. Numerical calculations were also conducted by solving unsteady three dimensional compressible Navier-Stokes equations with Baldwin-Lomax turbulence model. The main parameters for the dual jets are the non-dimensional distance between the two nozzle centers H/D covering 1.5, 2.0, the nozzle to plate separation L/D 2.0, 3.0,4.0 and 5.0 and the pressure ratio defined by Po/Pb 1.0~6.0, where D is the diameter of each nozzle exit, Po the stagnation pressure and Pb the back pressure. It is found that the agreement between the experiments and the calculations is good. The fountain flow at the middle of the two jets is observed both in the experiments and the calculation. According to FFT analysis of the experiments for the twin jets,relatively low frequency (up to 5 kHz) is dominant for H/D =1.5, L/D =2.0 and pressure ratio Po/Pb =3.0 and 5.0,which is confirmed by the experiments.

  7. A Danish population-based twin study on autism spectrum disorders

    DEFF Research Database (Denmark)

    Nordenbaek, Claudia; Jorgensen, Meta; Kyvik, Kirsten Ohm

    2014-01-01

    Genetic epidemiological studies of Autism Spectrum Disorders (ASDs) based on twin pairs ascertained from the population and thoroughly assessed to obtain a high degree of diagnostic validity are few. All twin pairs aged 3-14 years in the nationwide Danish Twin Registry were approached. A three......-step procedure was used. Five items from the "Child Behaviour Checklist" (CBCL) were used in the first screening phase, while screening in the second phase included the "Social and Communication Questionnaire" and the "Autism Spectrum Screening Questionnaire". The final clinical assessment was based on "gold...

  8. Genomewide association study to detect QTL for twinning rate in ...

    Indian Academy of Sciences (India)

    Mohsen Gholizadeh, Ghodrat Rahimi-Mianji, Ardeshir Nejati-Javaremi, Dirk Jan De Koning and Elisabeth Jonas. J. Genet. 93, 489–493. Chromosome. 02468. − log. 10. (p. ) 1. 2. 3. 4 5 6 7. 9. 11 13 15 17 19. 22 25 27. Figure 1. Manhattan plot of the results from the genomewide association analysis for twinning during the ...

  9. Exploring Genetic and Environmental Effects in Dysphonia: A Twin Study

    Science.gov (United States)

    Simberg, Susanna; Santtila, Pekka; Soveri, Anna; Varjonen, Markus; Sala, Eeva; Sandnabba, N. Kenneth

    2009-01-01

    Purpose: To explore the existence of genetic effects as well as the interaction between potential genetic effects and a voice-demanding occupation on dysphonia. Method: One thousand seven hundred and twenty-eight Finnish twins (555 male; 1,173 female) born between 1961 and 1989 completed a questionnaire concerning vocal symptoms and occupation.…

  10. A study of diabetes mellitus within a large sample of Australian twins

    DEFF Research Database (Denmark)

    Condon, Julianne; Shaw, Joanne E; Luciano, Michelle

    2008-01-01

    with type 2 diabetes (T2D), 41 female pairs with gestational diabetes (GD), 5 pairs with impaired glucose tolerance (IGT) and one pair with MODY. Heritabilities of T1D, T2D and GD were all high, but our samples did not have the power to detect effects of shared environment unless they were very large......Twin studies of diabetes mellitus can help elucidate genetic and environmental factors in etiology and can provide valuable biological samples for testing functional hypotheses, for example using expression and methylation studies of discordant pairs. We searched the volunteer Australian Twin...... Registry (19,387 pairs) for twins with diabetes using disease checklists from nine different surveys conducted from 1980-2000. After follow-up questionnaires to the twins and their doctors to confirm diagnoses, we eventually identified 46 pairs where one or both had type 1 diabetes (T1D), 113 pairs...

  11. The Heritability of Prostate Cancer in the Nordic Twin Study of Cancer

    DEFF Research Database (Denmark)

    von Bornemann Hjelmborg, Jacob; Scheike, Thomas; Holst, Klaus

    2014-01-01

    Background: Prostate cancer is thought to be the most heritable cancer, although little is known about how this genetic contribution varies across age. Methods: To address this question, we undertook the world’s largest prospective study in the Nordic Twin Study of Cancer cohort, including 18...... risk and liability. Results: The cumulative risk of prostate cancer was similar to that of the background population. The cumulative risk for twins whose co-twin was diagnosed with prostate cancer was greater for MZ than for DZ twins across all ages. Among concordantly affected pairs, the time between...... diagnoses was significantly shorter for MZ than DZ pairs (median 3.8 versus 6.5 years, respectively). Genetic differences contributed substantially to variation in both the risk and the liability (heritability=58% (95% CI 52%–63%) of developing prostate cancer. The relative contribution of genetic factors...

  12. Post-traumatic stress disorder and incidence of coronary heart disease: a twin study.

    Science.gov (United States)

    Vaccarino, Viola; Goldberg, Jack; Rooks, Cherie; Shah, Amit J; Veledar, Emir; Faber, Tracy L; Votaw, John R; Forsberg, Christopher W; Bremner, J Douglas

    2013-09-10

    The aim of this study was to determine whether post-traumatic stress disorder (PTSD) is associated with coronary heart disease (CHD) using a prospective twin study design and objective measures of CHD. It has long been hypothesized that PTSD increases the risk of CHD, but empirical evidence using objective measures is limited. We conducted a prospective study of middle-aged male twins from the Vietnam Era Twin Registry. Among twin pairs without self-reported CHD at baseline, we selected pairs discordant for a lifetime history of PTSD, pairs discordant for a lifetime history of major depression, and pairs without either condition. All underwent a clinic visit after a median follow-up of 13 years. Outcomes included clinical events (myocardial infarction, other hospitalizations for CHD and coronary revascularization) and quantitative measures of myocardial perfusion by [(13)N] ammonia positron emission tomography, including a stress total severity score and coronary flow reserve. A total of 562 twins (281 pairs) with a mean age of 42.6 years at baseline were included in this study. The incidence of CHD was more than double in twins with PTSD (22.6%) than in those without PTSD (8.9%; p Stress total severity score was significantly higher (+95%, p = 0.001) and coronary flow reserve was lower (-0.21, p = 0.02) in twins with PTSD than in those without PTSD, denoting worse myocardial perfusion. Associations were only mildly attenuated in 117 twin pairs discordant for PTSD. Among Vietnam-era veterans, PTSD is a risk factor for CHD. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  13. EFFECTS OF LONG-TERM PHYSICAL ACTIVITY ON CARDIAC STRUCTURE AND FUNCTION: A TWIN STUDY

    Directory of Open Access Journals (Sweden)

    Urho M.Kujala

    2009-12-01

    Full Text Available Previous studies have shown that athletic training or other physical activity causes structural and functional adaptations in the heart, but less is known how long-term physical activity affects heart when genetic liability and childhood environment are taken into account. The aim of this study was to investigate the effects of long-term physical activity vs. inactivity on cardiac structure and function in twin pairs discordant for physical activity for 32 years. Twelve same-sex twin pairs (five monozygotic and seven dizygotic, 50-67 years were studied as a part of the TWINACTIVE study. Discordance in physical activity was initially determined in 1975 and it remained significant throughout the follow-up. At the end of the follow-up in 2007, resting echocardiographic and electrocardiographic measurements were performed. During the follow-up period, the active co-twins were on average 8.2 (SD 4.0 MET hours/day more active than their inactive co-twins (p < 0.001. At the end of the follow-up, resting heart rate was lower in the active than inactive co-twins [59 (SD 5 vs. 68 (SD 10 bpm, p=0.03]. The heart rate-corrected QT interval was similar between the co-twins. Also, there was a tendency for left ventricular mass per body weight to be greater and T wave amplitude in lead II to be higher in the active co-twins (18% and 15%, respectively, p=0.08 for both. Similar trends were found for both monozygotic and dizygotic twin pairs. In conclusion, the main adaptation to long- term physical activity is lowered resting heart rate, even after partially or fully controlling for genetic liability and childhood environment

  14. Predictors of fibromyalgia: a population-based twin cohort study.

    Science.gov (United States)

    Markkula, Ritva A; Kalso, Eija A; Kaprio, Jaakko A

    2016-01-15

    Fibromyalgia (FM) is a pain syndrome, the mechanisms and predictors of which are still unclear. We have earlier validated a set of FM-symptom questions for detecting possible FM in an epidemiological survey and thereby identified a cluster with "possible FM". This study explores prospectively predictors for membership of that FM-symptom cluster. A population-based sample of 8343 subjects of the older Finnish Twin Cohort replied to health questionnaires in 1975, 1981, and 1990. Their answers to the set of FM-symptom questions in 1990 classified them in three latent classes (LC): LC1 with no or few symptoms, LC2 with some symptoms, and LC3 with many FM symptoms. We analysed putative predictors for these symptom classes using baseline (1975 and 1981) data on regional pain, headache, migraine, sleeping, body mass index (BMI), physical activity, smoking, and zygosity, adjusted for age, gender, and education. Those with a high likelihood of having fibromyalgia at baseline were excluded from the analysis. In the final multivariate regression model, regional pain, sleeping problems, and overweight were all predictors for membership in the class with many FM symptoms. The strongest non-genetic predictor was frequent headache (OR 8.6, CI 95% 3.8-19.2), followed by persistent back pain (OR 4.7, CI 95% 3.3-6.7) and persistent neck pain (OR 3.3, CI 95% 1.8-6.0). Regional pain, frequent headache, and persistent back or neck pain, sleeping problems, and overweight are predictors for having a cluster of symptoms consistent with fibromyalgia.

  15. Bidirectional influences between maternal parenting and children's peer problems: a longitudinal monozygotic twin difference study.

    Science.gov (United States)

    Yamagata, Shinji; Takahashi, Yusuke; Ozaki, Koken; Fujisawa, Keiko K; Nonaka, Koichi; Ando, Juko

    2013-03-01

    This twin study examined the bidirectional relationship between maternal parenting behaviors and children's peer problems that were not confounded by genetic and family environmental factors. Mothers of 259 monozygotic twin pairs reported parenting behaviors and peer problems when twins were 42 and 48 months. Path analyses on monozygotic twin difference scores revealed that authoritative parenting (the presence of consistent discipline and lack of harsh parenting) and peer problems simultaneously influenced each other. Authoritative parenting reduced peer problems, and peer problems increased authoritative parenting. Neither consistent discipline nor harsh parenting alone was associated with peer problems. These results suggest that maternal authoritative parenting works protectively in regard to children's peer problems, and peer problems can evoke such effective parenting. © 2012 Blackwell Publishing Ltd.

  16. Psychiatric outcomes of bullying victimization: a study of discordant monozygotic twins.

    Science.gov (United States)

    Silberg, J L; Copeland, W; Linker, J; Moore, A A; Roberson-Nay, R; York, T P

    2016-07-01

    Bullying victimization in childhood is associated with a broad array of serious mental health disturbances, including anxiety, depression, and suicidal ideation and behavior. The key goal of this study was to evaluate whether bullying victimization is a true environmental risk factor for psychiatric disturbance using data from 145 bully-discordant monozygotic (MZ) juvenile twin pairs from the Virginia Twin Study of Adolescent Behavioral Development (VTSABD) and their follow-up into young adulthood. Since MZ twins share an identical genotype and familial environment, a higher rate of psychiatric disturbance in a bullied MZ twin compared to their non-bullied MZ co-twin would be evidence of an environmental impact of bullying victimization. Environmental correlations between being bullied and the different psychiatric traits were estimated by fitting structural equation models to the full sample of MZ and DZ twins (N = 2824). Environmental associations were further explored using the longitudinal data on the bullying-discordant MZ twins. Being bullied was associated with a wide range of psychiatric disorders in both children and young adults. The analysis of data on the MZ-discordant twins supports a genuine environmental impact of bullying victimization on childhood social anxiety [odds ratio (OR) 1.7], separation anxiety (OR 1.9), and young adult suicidal ideation (OR 1.3). There was a shared genetic influence on social anxiety and bullying victimization, consistent with social anxiety being both an antecedent and consequence of being bullied. Bullying victimization in childhood is a significant environmental trauma and should be included in any mental health assessment of children and young adults.

  17. Twin studies advance the understanding of gene-environment interplay in human nutrigenomics.

    Science.gov (United States)

    Pallister, Tess; Spector, Tim D; Menni, Cristina

    2014-12-01

    Investigations into the genetic architecture of diet-disease relationships are particularly relevant today with the global epidemic of obesity and chronic disease. Twin studies have demonstrated that genetic makeup plays a significant role in a multitude of dietary phenotypes such as energy and macronutrient intakes, dietary patterns, and specific food group intakes. Besides estimating heritability of dietary assessment, twins provide a naturally unique, case-control experiment. Due to their shared upbringing, matched genes and sex (in the case of monozygotic (MZ) twin pairs), and age, twins provide many advantages over classic epidemiological approaches. Future genetic epidemiological studies could benefit from the twin approach particularly where defining what is 'normal' is problematic due to the high inter-individual variability underlying metabolism. Here, we discuss the use of twins to generate heritability estimates of food intake phenotypes. We then highlight the value of discordant MZ pairs to further nutrition research through discovery and validation of biomarkers of intake and health status in collaboration with cutting-edge omics technologies.

  18. Risk and protective factors for Parkinson's disease: a study in Swedish twins.

    Science.gov (United States)

    Wirdefeldt, Karin; Gatz, Margaret; Pawitan, Yudi; Pedersen, Nancy L

    2005-01-01

    Many studies have shown a protective effect of cigarette smoking on Parkinson's disease. However, criticism has been raised concerning confounding by genetic factors. We investigated the associations between Parkinson's disease and smoking, alcohol, coffee, area of living, and education in a co-twin control study. Because twins are matched for genetic and familial environmental factors, this design controls for confounding by these factors. We also examined control subjects unrelated to cases. Exposure information was taken from questionnaires answered in the 1960s and 1970s. Parkinson's disease cases were identified through the Swedish Inpatient Discharge Register (IDR) and the Cause of Death Register. In the unrelated control subject comparison, 476 Parkinson's disease cases and 2,380 control subjects were included. In the co-twin control comparison, 415 same-sex twin pairs were included. There was an inverse association between smoking and Parkinson's disease using unrelated control subjects and co-twin control cases. There was no association between Parkinson's disease and alcohol, coffee, or area of living. High educational level was associated with Parkinson's disease in the unrelated control subject comparison but not in the co-twin control comparison. We confirm the protective effect of smoking on Parkinson's disease and establish that the association is only partially explained by genetic and familial environmental factors.

  19. Do MZ twins have discordant experiences of friendship? A qualitative hypothesis-generating MZ twin differences study

    Science.gov (United States)

    Moran, Nicola; Plomin, Robert

    2017-01-01

    Using a qualitative monozygotic (MZ) twin differences design we explored whether adolescent MZ twins report discordant peer relationships and, if so, whether they perceive them as causes, consequences or correlates of discordant behaviour. We gathered free-response questionnaire data from 497 families and conducted in-depth telephone interviews with 97 of them. Within this dataset n = 112 families (23% of the sample) described discordant peer relationships. Six categories of discordance were identified (peer victimisation, peer rejection, fewer friends, different friends, different attitudes to friendship and dependence on co-twin). Participants described peer relationship discordance arising as a result of chance occurrences, enhanced vulnerability in one twin or discordant behaviour. Consequences of discordant peer relationships were seen as discordance in self-confidence, future plans, social isolation, mental health and interests. In all cases the twin with worse peer experiences was seen as having a worse outcome. Specific hypotheses are presented. PMID:28727730

  20. Hallux Valgus, By Nature or Nurture? A Twin Study.

    Science.gov (United States)

    Munteanu, Shannon E; Menz, Hylton B; Wark, John D; Christie, Jemma J; Scurrah, Katrina J; Bui, Minh; Erbas, Bircan; Hopper, John L; Wluka, Anita E

    2017-09-01

    To evaluate the contributions of shared but unmeasured genetic and environmental factors to hallux valgus (HV). Between 2011 and 2012, 74 monozygotic (MZ) and 56 dizygotic (DZ) female twin pairs self-reported HV and putative risk factors, including footwear use across their lifespan. Estimates of casewise concordance (P C ), correlation (ρ), and odds ratios (ORs) were calculated, adjusting for age and other risk factors, and compared between MZ and DZ pairs using logistic regression, generalized estimating equations, and a maximum likelihood-based method, respectively. A total of 70 participants (27%) reported HV, with 12 MZ and 7 DZ pairs being concordant. After adjusting for age, twins were correlated (ρ = 0.27 [95% confidence interval (95% CI) 0.08, 0.46]) and concordant (P C  = 0.45 [95% CI 0.29, 0.61]; mean age 58 years), with no difference between MZ and DZ pairs (P = 0.7). HV was associated with regularly wearing footwear with a constrictive toe-box during the fourth decade (adjusted OR 2.73 [95% CI 1.12, 6.67]). This risk factor was correlated in MZ (ρ = 0.38 [95% CI 0.15, 0.60]) but not DZ (ρ = -0.20 [95% CI -0.43, 0.03]) pairs. These correlations were significantly different (P = 0.002). Twins are correlated for HV, but we found no evidence that correlation was due to shared genetic factors. We identified an environmental risk factor, footwear with a constrictive toe-box, that is not shared to the same extent by MZ and DZ pairs, contrary to the assumption of the classic twin model. Footwear, and possibly genetic factors and unknown shared environmental factors, could contribute to developing HV. © 2016, American College of Rheumatology.

  1. Risk factors for asthma in young adults: a co-twin control study

    DEFF Research Database (Denmark)

    Thomsen, SF; Ulrik, Charlotte Suppli; Kyvik, KO

    2006-01-01

    BACKGROUND: The liability to asthma is influenced both by genetic and environmental factors. The objective of this study was to identify risk factors for asthma in young adult twin pairs during an 8-year period. METHODS: From the birth cohorts 1953-1982 of the Danish Twin Registry, 6,090 twin pairs....... Pairs in which only one twin developed asthma -- discordant pairs -- were identified and conditional logistic regression was applied to detect effects of risk factors. RESULTS: A total of 126 monozygotic (MZ) and 273 dizygotic (DZ) discordant twin pairs were identified. In MZ twins hay fever (OR = 3...... and females = 0.54, 95% CI: 0.36-0.80, P = 0.002), and increasing levels of body mass index (BMI; OR per unit = 1.11, 95% CI: 1.02-1.20, P = 0.009) were significant predictors of asthma. CONCLUSIONS: Hay fever, eczema, female sex, exercise and increasing levels of BMI were risk factors for asthma in young...

  2. A STUDY OF PERINATAL OUTCOME IN TWIN GESTATION IN A TERTIARY CARE CENTER

    Directory of Open Access Journals (Sweden)

    Rinku Girija

    2017-02-01

    Full Text Available BACKGROUND Perinatal mortality is an index of obstetric care. Twin pregnancy is a high-risk pregnancy since most often the foetus in born prematurely or retarded physically; it may turn out to be a dreaded event, especially in rare instances of simultaneous death of twins or death of one twin in mid trimester thereby worsening the prognosis of the surviving twin. The aim of the study is to study the perinatal mortality and morbidity of twin gestation and factors affecting the same in a tertiary care center. MATERIALS AND METHODS This is a prospective study. 100 successive cases of multiple pregnancy beyond 28 weeks of gestation admitted during the study period were followed from the antenatal period upon their admission to the antenatal ward and the labour room. 100 cases of singleton pregnancies during the same period taken as control. Detailed obstetric history, family history of twins, intake of ovulation inducing agents, time of diagnosis of twin pregnancy confirmed by USS examination were noted. Maternal antenatal complications like anaemia, hypertension, jaundice, etc. noted. The mode of onset of labour, presentation of foetus noted and if possible confirmed by USS, routine and special investigation like PIH profile, FBS, PPBS. Doppler USS done wherever necessary. Study Setting and Design- It is a prospective observational study of 100 consecutive twin gestations of gestational age 28 weeks and above at a tertiary care hospital attached to Government Medical College, Thiruvananthapuram, for a period of 6 months. Perinatal outcome including perinatal morbidity and mortality in relation to gestational age, mode of delivery, chorionicity, birth weight of the baby and NICU admission were analysed. RESULTS Data collected was analysed with descriptive statistics like percentage, proportion, rates, ratio and chi-square test. CONCLUSION In spite of so many advances in Obstetrics and Neonatology, the perinatal mortality and morbidity in twin

  3. Research from the NASA Twins Study and Omics in Support of Mars Missions

    Science.gov (United States)

    Kundrot, C.; Shelhamer, M.; Scott, G.

    2015-01-01

    The NASA Twins Study, NASA's first foray into integrated omic studies in humans, illustrates how an integrated omics approach can be brought to bear on the challenges to human health and performance on a Mars mission. The NASA Twins Study involves US Astronaut Scott Kelly and his identical twin brother, Mark Kelly, a retired US Astronaut. No other opportunity to study a twin pair for a prolonged period with one subject in space and one on the ground is available for the foreseeable future. A team of 10 principal investigators are conducting the Twins Study, examining a very broad range of biological functions including the genome, epigenome, transcriptome, proteome, metabolome, gut microbiome, immunological response to vaccinations, indicators of atherosclerosis, physiological fluid shifts, and cognition. A novel aspect of the study is the integrated study of molecular, physiological, cognitive, and microbiological properties. Major sample and data collection from both subjects for this study began approximately six months before Scott Kelly's one year mission on the ISS, continue while Scott Kelly is in flight and will conclude approximately six months after his return to Earth. Mark Kelly will remain on Earth during this study, in a lifestyle unconstrained by this study, thereby providing a measure of normal variation in the properties being studied. An overview of initial results and the future plans will be described as well as the technological and ethical issues raised for spaceflight studies involving omics.

  4. Anorexia and bulimia nervosa in same-sex and opposite-sex twins: lack of association with twin type in a nationwide study of Finnish twins.

    Science.gov (United States)

    Raevuori, Anu; Kaprio, Jaakko; Hoek, Hans W; Sihvola, Elina; Rissanen, Aila; Keski-Rahkonen, Anna

    2008-12-01

    The authors tested the hypothesis that either prenatal feminization or masculinization hormone influences in utero or later socialization affects the risk for anorexia and bulimia nervosa and disordered eating in members of opposite-sex twin pairs. Finnish twins (N=2,426 women, N=1,962 men with known zygosity) from birth cohorts born 1974-1979 were assessed at age 22 to 28 years with a questionnaire for eating disorder symptoms. Based on the questionnaire screen, women (N=292), men (N=53), and their cotwins were interviewed to assess diagnoses of anorexia nervosa and bulimia nervosa (per DSM-IV and broad criteria). In women from opposite-sex twin pairs, the prevalence of DSM-IV or broad anorexia nervosa was not significantly different than that of women from monozygotic pairs or same-sex dizygotic pairs. Of the five male anorexia nervosa probands, only one was from an opposite-sex twin pair. Bulimia nervosa in men was too rare to be assessed by zygosity; the prevalence of DSM-IV or broad bulimia nervosa did not differ in women from opposite- versus same-sex twin pairs. In both sexes, the overall profile of indicators on eating disorders was rather similar between individuals from opposite- and same-sex pairs. The authors found little evidence that the risk for anorexia nervosa, bulimia nervosa, or disordered eating was associated with zygosity or sex composition of twin pairs, thus making it unlikely that in utero femininization or masculinization or socialization effects of growing up with an opposite-sex twin have a major influence on the later development of eating disorders.

  5. Efficacy of the Video-feedback Intervention to promote Positive Parenting and Sensitive Discipline in Twin Families (VIPP-Twins): Study protocol for a randomized controlled trial.

    Science.gov (United States)

    Euser, Saskia; Bakermans-Kranenburg, Marian J; van den Bulk, Bianca G; Linting, Mariëlle; Damsteegt, Rani C; Vrijhof, Claudia I; van Wijk, Ilse C; Crone, Eveline A; van IJzendoorn, Marinus H

    2016-06-06

    Intervention programs with the aim of enhancing parenting quality have been found to be differentially effective in decreasing negative child outcomes such as externalizing behavioral problems, resulting in modest overall effect sizes. Here we present the protocol for a randomized controlled trial to examine the efficacy of the Video-feedback Intervention to promote Positive Parenting and Sensitive Discipline for Twin Families (VIPP-Twins) on parenting quality and children's behavioral control and social competence. In addition, we aim to test the differential susceptibility theory; we examine differential efficacy of the intervention based on genetic make-up or temperament for both parents and children. Lastly, we explore neurobiological mechanisms underlying intervention effects on children's developmental outcomes. The original VIPP-SD was adapted for use in families with twins. The VIPP-Twins consists of five biweekly sessions in which the families are visited at home, parent-child interactions are videotaped and parents receive positive feedback on selected video fragments. Families (N = 225) with a same sex twin (mean age = 3.6 years) were recruited to participate in the study. The study consists of four assessments. After two baseline assessments in year 1 and year 2, a random 40 % of the sample will receive the VIPP-Twins program. The first post-test assessment will be carried out one month after the intervention and there will be a long term follow-up assessment two years after the intervention. Measures include observational assessments of parenting and children's social competence and behavioral control, and neurobiological assessments (i.e., hormonal functioning and neural (re-)activity). Results of the study will provide insights in the efficacy of the VIPP-Twins and reveal moderators and mediators of program efficacy. Overall the randomized controlled trial is an experimental test of the differential susceptibility theory. Dutch Trial

  6. A metric study of insole foot impressions in footwear of identical twins.

    Science.gov (United States)

    Nirenberg, Michael S; Krishan, Kewal; Kanchan, Tanuj

    2017-11-01

    Foot impressions are of utmost importance in crime scene investigations. Foot impressions are available in the form of barefoot prints, sock-clad footprints, and as impressions within footwear. Sometimes suspects leave their footwear at the crime scene, and the insole of this footwear may contain the foot impression of the suspect which may be important evidence linking him or her to the crime. The task of identification based on the analysis of footprints can be challenging when the footprints belonging to one of the identical twin is available for examination. The present study is based on the quantitative measures of the foot impressions in the footwear of adult identical twins. The study was conducted on four sets of female monozygotic twins from the United States of America. A total of 17 length and breadth measurements were taken on each foot impression. A combination of Reel Method and Extended Gunn Method was utilized to produce the measurements. The measurements of the foot impressions were compared among the twins on the right and the left side. Differences were found in the various footprint measurements among the twins. The study's sample size was not large enough to apply robust statistical tests, but the study is significant in that it presents the first detailed comparative analysis of a large number of measurements of insole foot impressions of adult twins. The observations derived from the study are likely to assist forensic investigations in cases involving the foot impressions of the twins. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  7. Heritability of Biomarkers of Oxidized Lipoproteins: Twin Pair Study.

    Science.gov (United States)

    Rao, Fangwen; Schork, Andrew J; Maihofer, Adam X; Nievergelt, Caroline M; Marcovina, Santica M; Miller, Elizabeth R; Witztum, Joseph L; O'Connor, Daniel T; Tsimikas, Sotirios

    2015-07-01

    To determine whether biomarkers of oxidized lipoproteins are genetically determined. Lipoprotein(a) (Lp[a]) is a heritable risk factor and carrier of oxidized phospholipids (OxPL). We measured oxidized phospholipids on apolipoprotein B-containing lipoproteins (OxPL-apoB), Lp(a), IgG, and IgM autoantibodies to malondialdehyde-modified low-density lipoprotein, copper oxidized low-density lipoprotein, and apoB-immune complexes in 386 monozygotic and dizygotic twins to estimate trait heritability (h(2)) and determine specific genetic effects among traits. A genome-wide linkage study followed by genetic association was performed. The h(2) (scale: 0-1) for Lp(a) was 0.91±0.01 and for OxPL-apoB 0.87±0.02, which were higher than physiological, inflammatory, or lipid traits. h(2) of IgM malondialdehyde-modified low-density lipoprotein, copper oxidized low-density lipoprotein, and apoB-immune complexes were 0.69±0.04, 0.67±0.05, and 0.80±0.03, respectively, and for IgG malondialdehyde-modified low-density lipoprotein, copper oxidized low-density lipoprotein, and apoB-immune complexes 0.62±0.05, 0.52±0.06, and 0.53±0.06, respectively. There was an inverse correlation between the major apo(a) isoform and OxPL-apoB (R=-0.49; Plipoprotein and copper oxidized low-density lipoprotein, and apoB-immune complexes. Sib-pair genetic linkage of the Lp(a) trait revealed that single nucleotide polymorphism rs10455872 was significantly associated with OxPL-apoB after adjusting for Lp(a). OxPL-apoB and other biomarkers of oxidized lipoproteins are highly heritable cardiovascular risk factors that suggest novel genetic origins of atherothrombosis. © 2015 American Heart Association, Inc.

  8. Examining the provisional guidelines for weight gain in twin pregnancies: a retrospective cohort study.

    Science.gov (United States)

    Lutsiv, Olha; Hulman, Adam; Woolcott, Christy; Beyene, Joseph; Giglia, Lucy; Armson, B Anthony; Dodds, Linda; Neupane, Binod; McDonald, Sarah D

    2017-09-29

    Weight gain during pregnancy has an important impact on maternal and neonatal health. Unlike the Institute of Medicine (IOM) recommendations for weight gain in singleton pregnancies, those for twin gestations are termed "provisional", as they are based on limited data. The objectives of this study were to determine the neonatal and maternal outcomes associated with gaining weight below, within and above the IOM provisional guidelines on gestational weight gain in twin pregnancies, and additionally, to explore ranges of gestational weight gain among women who delivered twins at the recommended gestational age and birth weight, and those who did not. A retrospective cohort study of women who gave birth to twins at ≥20 weeks gestation, with a birth weight ≥ 500 g was conducted in Nova Scotia, Canada (2003-2014). Our primary outcome of interest was small for gestational age (gain were used to categorize women as gaining below, within, or above guidelines. We performed traditional regression analyses for maternal outcomes, and to account for the correlated nature of the neonatal outcomes in twins, we used generalized estimating equations (GEE). A total of 1482 twins and 741 mothers were included, of whom 27%, 43%, and 30% gained below, within, and above guidelines, respectively. The incidence of small for gestational age in these three groups was 30%, 21%, and 20%, respectively, and relative to gaining within guidelines, the adjusted odds ratios were 1.44 (95% CI 1.01-2.06) for gaining below and 0.92 (95% CI 0.62-1.36) for gaining above. The gestational weight gain in women who delivered twins at 37-42 weeks with average birth weight ≥ 2500 g and those who delivered twins outside of the recommend ranges were comparable to each other and the IOM recommendations. While gestational weight gain below guidelines for twins was associated with some adverse neonatal outcomes, additional research exploring alternate ranges of gestational weight gain in twin

  9. A population-based study of gastroesophageal reflux disease and sleep problems in elderly twins.

    Directory of Open Access Journals (Sweden)

    Anna Lindam

    Full Text Available BACKGROUND & AIMS: Previous studies indicate an association between sleep problems and gastroesophageal reflux disease (GERD. Although both these conditions separately have moderate heritabilities, confounding by genetic factors has not previously been taken into account. This study aimed to reveal the association between sleep problems and GERD, while adjusting for heredity and other potential confounding factors. METHODS: This cross-sectional population-based study included all 8,014 same-sexed twins of at least 65 years of age and born in Sweden between 1886 and 1958, who participated in telephone interviews in 1998-2002. Three logistic regression models were used 1 external control analysis, 2 within-pair co-twin analysis with dizygotic (DZ twin pairs discordant for GERD, and 3 within-pair co-twin analysis with monozygotic (MZ twin pairs discordant for GERD. Odds ratios (ORs with 95% confidence intervals (CIs were calculated and adjusted for established risk factors for GERD, i.e. sex, age, body mass index (BMI, tobacco smoking, and educational level. RESULTS: A dose-response association was identified between increasing levels of sleep problems and GERD in the external control analysis. Individuals who often experienced sleep problems had a two-fold increased occurrence of GERD compared to those who seldom had sleep problems (OR 2.0, 95% CI 1.8-2.4. The corresponding association was of similar strength in the co-twin analysis including 356 DZ pairs (OR 2.2, 95% CI 1.6-3.4, and in the co-twin analysis including 210 MZ pairs (OR 1.5, 95% CI 0.9-2.7. CONCLUSION: A dose-dependent association between sleep problems and GERD remains after taking heredity and other known risk factors for GERD into account.

  10. A twin study of schizoaffective-mania, schizoaffective-depression, and other psychotic syndromes.

    Science.gov (United States)

    Cardno, Alastair G; Rijsdijk, Frühling V; West, Robert M; Gottesman, Irving I; Craddock, Nick; Murray, Robin M; McGuffin, Peter

    2012-03-01

    The nosological status of schizoaffective disorders remains controversial. Twin studies are potentially valuable for investigating relationships between schizoaffective-mania, schizoaffective-depression, and other psychotic syndromes, but no such study has yet been reported. We ascertained 224 probandwise twin pairs [106 monozygotic (MZ), 118 same-sex dizygotic (DZ)], where probands had psychotic or manic symptoms, from the Maudsley Twin Register in London (1948-1993). We investigated Research Diagnostic Criteria schizoaffective-mania, schizoaffective-depression, schizophrenia, mania and depressive psychosis primarily using a non-hierarchical classification, and additionally using hierarchical and data-derived classifications, and a classification featuring broad schizophrenic and manic syndromes without separate schizoaffective syndromes. We investigated inter-rater reliability and co-occurrence of syndromes within twin probands and twin pairs. The schizoaffective syndromes showed only moderate inter-rater reliability. There was general significant co-occurrence between syndromes within twin probands and MZ pairs, and a trend for schizoaffective-mania and mania to have the greatest co-occurrence. Schizoaffective syndromes in MZ probands were associated with relatively high risk of a psychotic syndrome occurring in their co-twins. The classification of broad schizophrenic and manic syndromes without separate schizoaffective syndromes showed improved inter-rater reliability, but high genetic and environmental correlations between the two broad syndromes. The results are consistent with regarding schizoaffective-mania as due to co-occurring elevated liability to schizophrenia, mania, and depression; and schizoaffective-depression as due to co-occurring elevated liability to schizophrenia and depression, but with less elevation of liability to mania. If in due course schizoaffective syndromes show satisfactory inter-rater reliability and some specific etiological

  11. Familial resemblance in religiousness in a secular society: a twin study.

    Science.gov (United States)

    Hvidtjørn, Dorte; Petersen, Inge; Hjelmborg, Jacob; Skytthe, Axel; Christensen, Kaare; Hvidt, Niels C

    2013-04-01

    It is well known that human behavior and individual psychological traits are moderately to substantially heritable. Over the past decade, an increasing number of studies have explored the genetic and environmental influence on religiousness. These studies originate predominantly from countries generally considered more religious than the very secular northern European countries. Comparisons of the results are complicated by diverse definitions of religiousness, but several studies indicate that the influence of the family environment is most predominant in early life, whereas genetic influences increase with age. We performed a population-based twin study of religiousness in a secular society using data from a Web-based survey sent to 6,707 Danish twins born 1970-1989, who were identified in the Danish Twin Registry. We applied Fishman's three conceptual dimensions of religiousness: cognition, practice, and importance. In all polygenic models and biometric analyses, we controlled for gender and age. The study sample comprised 2,237 same sex twins, a response rate of 45%. We found high correlations within both monozygotic and dizygotic twin pairs in most items of religiousness, indicating a large influence from shared environmental factors. Personal religiousness such as praying to God, believing in God, and finding strength and comfort in religion were more influenced by genetic factors than were social forms of religiousness such as church attendance. We found a small tendency for increasing genetic influence with increasing age for some religious items, but not for all.

  12. The Twins Study: NASA's First Foray into 21st Century Omics Research

    Science.gov (United States)

    Kundrot, C. E.; Shelhamer, M.; Scott, G. B. I.

    2015-01-01

    The full array of 21st century omics-based research methods should be intelligently employed to reduce the health and performance risks that astronauts will be exposed to during exploration missions beyond low Earth Orbit. In March of 2015, US Astronaut Scott Kelly will launch to the International Space Station for a one year mission while his twin brother, Mark Kelly, a retired US Astronaut, remains on the ground. This situation presents an extremely rare flight opportunity to perform an integrated omics-based demonstration pilot study involving identical twin astronauts. A group of 10 principal investigators has been competitively selected, funded, and teamed together to form the Twins Study. A very broad range of biological function are being examined including the genome, epigenome, transcriptome, proteome, metabolome, gut microbiome, immunological response to vaccinations, indicators of atherosclerosis, physiological fluid shifts, and cognition. The plans for the Twins Study and an overview of initial results will be described as well as the technological and ethical issues raised for such spaceflight studies. An anticipated outcome of the Twins Study is that it will place NASA on a trajectory of using omics-based information to develop precision countermeasures for individual astronauts.

  13. Long term costs and effects of reducing the number of twin pregnancies in IVF by single embryo transfer: the TwinSing study.

    Science.gov (United States)

    van Heesch, Mirjam M J; Bonsel, Gouke J; Dumoulin, John C M; Evers, Johannes L H; van der Hoeven, Mark Ahbm; Severens, Johan L; Dykgraaf, Ramon H M; van der Veen, Fulco; Tonch, Nino; Nelen, Willianne L D M; van Zonneveld, Piet; van Goudoever, Johannes B; Tamminga, Pieter; Steiner, Katerina; Koopman-Esseboom, Corine; van Beijsterveldt, Catharina E M; Boomsma, Dorret I; Snellen, Diana; Dirksen, Carmen D

    2010-10-20

    Pregnancies induced by in vitro fertilisation (IVF) often result in twin gestations, which are associated with both maternal and perinatal complications. An effective way to reduce the number of IVF twin pregnancies is to decrease the number of embryos transferred from two to one. The interpretation of current studies is limited because they used live birth as outcome measure and because they applied limited time horizons. So far, research on long-term outcomes of IVF twins and singletons is scarce and inconclusive. The objective of this study is to investigate the short (1-year) and long-term (5 and 18-year) costs and health outcomes of IVF singleton and twin children and to consider these in estimating the cost-effectiveness of single embryo transfer compared with double embryo transfer, from a societal and a healthcare perspective. A multi-centre cohort study will be performed, in which IVF singletons and IVF twin children born between 2003 and 2005 of whom parents received IVF treatment in one of the five participating Dutch IVF centres, will be compared. Data collection will focus on children at risk of health problems and children in whom health problems actually occurred. First year of life data will be collected in approximately 1,278 children (619 singletons and 659 twin children). Data up to the fifth year of life will be collected in approximately 488 children (200 singletons and 288 twin children). Outcome measures are health status, health-related quality of life and costs. Data will be obtained from hospital information systems, a parent questionnaire and existing registries. Furthermore, a prognostic model will be developed that reflects the short and long-term costs and health outcomes of IVF singleton and twin children. This model will be linked to a Markov model of the short-term cost-effectiveness of single embryo transfer strategies versus double embryo transfer strategies to enable the calculation of the long-term cost-effectiveness. This is

  14. Long term costs and effects of reducing the number of twin pregnancies in IVF by single embryo transfer: the TwinSing study

    Directory of Open Access Journals (Sweden)

    van Goudoever Johannes B

    2010-10-01

    Full Text Available Abstract Background Pregnancies induced by in vitro fertilisation (IVF often result in twin gestations, which are associated with both maternal and perinatal complications. An effective way to reduce the number of IVF twin pregnancies is to decrease the number of embryos transferred from two to one. The interpretation of current studies is limited because they used live birth as outcome measure and because they applied limited time horizons. So far, research on long-term outcomes of IVF twins and singletons is scarce and inconclusive. The objective of this study is to investigate the short (1-year and long-term (5 and 18-year costs and health outcomes of IVF singleton and twin children and to consider these in estimating the cost-effectiveness of single embryo transfer compared with double embryo transfer, from a societal and a healthcare perspective. Methods/Design A multi-centre cohort study will be performed, in which IVF singletons and IVF twin children born between 2003 and 2005 of whom parents received IVF treatment in one of the five participating Dutch IVF centres, will be compared. Data collection will focus on children at risk of health problems and children in whom health problems actually occurred. First year of life data will be collected in approximately 1,278 children (619 singletons and 659 twin children. Data up to the fifth year of life will be collected in approximately 488 children (200 singletons and 288 twin children. Outcome measures are health status, health-related quality of life and costs. Data will be obtained from hospital information systems, a parent questionnaire and existing registries. Furthermore, a prognostic model will be developed that reflects the short and long-term costs and health outcomes of IVF singleton and twin children. This model will be linked to a Markov model of the short-term cost-effectiveness of single embryo transfer strategies versus double embryo transfer strategies to enable the

  15. Genetic contribution to the relationship between social role function and depressive symptoms in Japanese elderly twins: a twin study.

    Science.gov (United States)

    Nishihara, Reiko; Inui, Fujio; Kato, Kenji; Tomizawa, Rie; Hayakawa, Kazuo

    2011-03-01

    Social role function is the capacity to maintain interpersonal relationships and is essential for being independent in the community. Limitations in social role function often coexist with depressive symptoms, suggesting a possible common mechanistic basis. We investigated whether the observed association between these traits is mainly a result of genetic or environmental influences. In 2008, a questionnaire was sent to 745 male twins aged 65 years and older. Our sample included 397 male twins. The number of monozygotic twins was 302, and dizygotic was 95. Among the twin pairs for whom data were available for both twins, 75 twin pairs (150 individuals) were monozygotic and 28 pairs (56 individuals) were dizygotic. Social role function was assessed using the Tokyo Metropolitan Institute of Gerontology Index of Competence. Depressive symptoms were measured by the 15-item version of the Geriatric Depression Scale. Relative importance of genes and environments for the phenotypes was calculated using structural equation analyses. Our results show that genetic influence was the major contributor to the relationship between social role function and depressive symptoms, and non-shared environmental influence was important for overall variation in each trait. We concluded that focusing on a non-shared environment is an essential approach for maintaining social role function and psychological well-being. It is suggested that treatments specific to depressive symptoms are more effective than indirect intervention targeting social role function. © 2011 The Authors. Psychogeriatrics © 2011 Japanese Psychogeriatric Society.

  16. The genetic and environmental influences on childhood obesity: a systematic review of twin and adoption studies

    DEFF Research Database (Denmark)

    Silventoinen, K; Rokholm, B; Kaprio, J

    2010-01-01

    a substantial effect in mid-childhood, but this effect disappeared at adolescence. Adoption studies supported the role of family environment in childhood obesity as correlations were found between adoptees and adoptive parents; however, correlations were substantially stronger between parents......In this systematic review, we aimed to collect together all previous twin and adoption studies on childhood and adolescent obesity up to the age of 18 years. Using several sources, we identified nine twin and five adoption studies; all of these studies had used relative weight as an indicator...

  17. Association of Educational Level and Marital Status With Obesity: A Study of Chinese Twins.

    Science.gov (United States)

    Liao, Chunxiao; Gao, Wenjing; Cao, Weihua; Lv, Jun; Yu, Canqing; Wang, Shengfeng; Li, Chunxiao; Pang, Zengchang; Cong, Liming; Dong, Zhong; Wu, Fan; Wang, Hua; Wu, Xianping; Jiang, Guohong; Wang, Xiaojie; Wang, Binyou; Li, Liming

    2018-04-01

    The prevalence of overweight and obesity is growing rapidly in many countries. Socioeconomic inequalities might be important for this increase. The aim of this study was to determine associations of body mass index (BMI), overweight and obesity with educational level and marital status in Chinese twins. Participants were adult twins recruited through the Chinese National Twin Registry (CNTR), aged 18 to 79 years, and the sample comprised 10,448 same-sex twin pairs. Current height, weight, educational attainment, and marital status were self-reported. Regression analyses and structural equation models were conducted to evaluate BMI, overweight, and obesity associated with educational level and marital status in both sexes. At an individual level, both educational level and marital status were associated with higher BMI and higher risk of being overweight and obesity in men, while in women the effects of educational level on BMI were in the opposite direction. In within-Monozygotic (MZ) twin-pair analyses, the effects of educational level on BMI disappeared in females. Bivariate structural equation models showed that genetic factors and shared environmental confounded the relationship between education and BMI in females, whereas marital status was associated with BMI on account of significant positive unique environmental correlation apart in both sexes. The present data suggested that marital status and BMI were associated, independent of familiar factors, for both sexes of this study population, while common genetic and shared environmental factors contributed to education-associated disparities in BMI in females.

  18. Can prematurity risk in twin pregnancies after in vitro fertilization be predicted? A retrospective study

    Directory of Open Access Journals (Sweden)

    Barad David

    2009-01-01

    Full Text Available Abstract Background Assisted reproduction (ART contributes to world-wide increases of twin pregnancies, in turn raising prematurity risks. Whether characteristics of ART cycles, resulting in twin gestations, can predict prematurity risks was the subject of this study. Methods One-hundred-and-six women, ages 20 to 39 years, with consecutive dichorionic-diamniotic (DC/DA twin gestations were retrospectively investigated. All pregnancies investigated followed fresh ART cycles, with use of autologous gamets, and were delivered at a university-based high-risk, maternal-fetal medicine unit. Only premature deliveries (i.e., <37.0 weeks gestational age, with viable neonate(s of ≥ 500 grams, were considered for analysis. Results After 1.8 +/- 1.2 ART cycles, 11.0 +/- 5.4 oocytes were retrieved and 2.4 +/- 0.9 embryos transferred in 106 women aged 31.6 +/- 4.2 years. Indications for ART treatment were male factor in 51.9%, female infertility in 27.4% and combined infertility in 20.8%. Though maternal age significantly influenced prematurity risk (p < 0.05, paternal age, maternal body mass index, indications for fertility treatment, number of previous ART attempts, oocytes retrieved or embryos transferred, as well as stimulation protocols and previous ART pregnancies, were not associated with gestational duration in twin pregnancies. Summary Except for female age, baseline and ART cycle characteristics do not allow for prediction of prematurity risk in dichorionic twin gestations after assisted reproduction.

  19. Genetic and Environmental Influences on the Mental Health of Children: A Twin Study.

    Science.gov (United States)

    Yin, Ping; Hou, Xiao; Qin, Qing; Deng, Wei; Hu, Hua; Luo, Qinghua; Du, Lian; Qiu, Haitang; Qiu, Tian; Fu, Yixiao; Meng, Huaqing; Li, Tao

    2016-08-01

    The current study explored the influences of genetic and environmental factors on the mental health of twins between ages 6 and 16. A total of 41 monozygotic (MZ) twins and 35 dizygotic twins were recruited. The psychological attributes and environmental information of children were evaluated. A significant correlation was found between twins in the diagnostic categories of any psychiatric disorder and attention deficit/hyperactivity disorder (ADHD)/hyperkinesis based on the Strengths and Difficulties Questionnaire scale in MZ twins. Furthermore, fathers' authoritarian parenting style was positively correlated with the probability of any psychiatric disorders and oppositional/conduct disorders, whereas mothers' authoritative parenting style was negatively correlated with the probability of any psychiatric disorders and ADHD/hyperkinesis. The probability of emotional disorders was negatively correlated with scores on the Stressful Life Events Scale. These results collectively suggest that genetic and environmental elements, such as parental rearing style and stressful life events, may influence children's mental health. [Journal of Psychosocial Nursing and Mental Health Services, 54(8), 29-34.]. Copyright 2016, SLACK Incorporated.

  20. Abnormal N400 Semantic Priming Effect May Reflect Psychopathological Processes in Schizophrenia: A Twin Study

    Directory of Open Access Journals (Sweden)

    Anuradha Sharma

    2017-01-01

    Full Text Available Objective. Activation of semantic networks is indexed by the N400 effect. We used a twin study design to investigate whether N400 effect abnormalities reflect genetic/trait liability or are related to psychopathological processes in schizophrenia. Methods. We employed robust linear regression to compare N400 and behavioral priming effects across 36 monozygotic twin pairs (6 pairs concordant for schizophrenia/schizoaffective disorder, 11 discordant pairs, and 19 healthy control pairs performing a lexical decision task. Moreover, we examined the correlation between Brief Psychiatric Rating Scale (BPRS score and the N400 effect and the influence of medication status on this effect. Results. Regression yielded a significant main effect of group on the N400 effect only in the direct priming condition (p=0.003. Indirect condition and behavioral priming effect showed no significant effect of group. Planned contrasts with the control group as a reference group revealed that affected concordant twins had significantly reduced N400 effect compared to controls, and discordant affected twins had a statistical trend for reduced N400 effect compared to controls. The unaffected twins did not differ significantly from the controls. There was a trend for correlation between reduced N400 effect and higher BPRS scores, and the N400 effect did not differ significantly between medicated and unmedicated patients. Conclusions. Reduced N400 effect may reflect disease-specific processes in schizophrenia implicating frontotemporal brain network in schizophrenia pathology.

  1. Twin study of heritability of eating bread in Danish and Finnish men and women.

    Science.gov (United States)

    Hasselbalch, Ann L; Silventoinen, Karri; Keskitalo, Kaisu; Pietiläinen, Kirsi H; Rissanen, Aila; Heitmann, Berit L; Kyvik, Kirsten O; Sørensen, Thorkild I A; Kaprio, Jaakko

    2010-04-01

    Bread is an elementary part of the western diet, and especially rye bread is regarded as an important source of fibre. We investigated the heritability of eating bread in terms of choice of white and rye bread and use-frequency of bread in female and male twins in Denmark and Finland. The study cohorts included 575 Danish (age range 18-67 years) and 2009 Finnish (age range 22-27 years) adult twin pairs. Self-reported frequency of eating bread was obtained by food frequency questionnaires. Univariate models based on linear structural equations for twin data were used to estimate the relative magnitude of the additive genetic, shared environmental and individual environmental effects on bread eating frequency and choice of bread. The analysis of bread intake frequency demonstrated moderate heritability ranging from 37-40% in the Finnish cohort and 23-26% in the Danish cohort. The genetic influence on intake of white bread was moderate (24-31%), while the genetic influence on intake of rye bread was higher in men (41-45%) than in women (24-33%). Environmental influences shared by the twins were not significant. Consumption of bread as well as choice of bread is influenced by genetic predisposition. Environmental factors shared by the co-twins (e.g., childhood environment) seem to have no significant effects on bread consumption and preference in adulthood.

  2. Losing one twin in the NICU - A case study of parental experience

    DEFF Research Database (Denmark)

    Aagaard, Hanne; Storm, Ida; Klitgaard, Jeannett

    2016-01-01

    and revealed tree overall themes. These themes indicate that besides struggling with grief related to the loss of one infant, the parents were challenged by the medical discourse, the lack of staff continuity and space to develop parenthood. This case study emphasizes how the loss of a premature twin......The aim of this case study was to generate a deeper understanding of parents’ experiences of losing one twin in the NICU. In an in-depth interview the parents told their story of giving birth to twins born extremely preterm and shortly after losing one of them. A thematic analysis was conducted...... reinforced the parents’ need of an understandable dialogue with a team of nurses. Furthermore the nurses have to offer a close partnership and create the necessary space for parents to develop parenthood while simultaneously dealing with the unexpected and traumatising circumstances related to the loss...

  3. Genetic and environmental influences on adolescents' smoking involvement: a multi-informant twin study.

    Science.gov (United States)

    Seglem, Karoline Brobakke; Waaktaar, Trine; Ask, Helga; Torgersen, Svenn

    2015-03-01

    Studying monozygotic and dizygotic adolescent twin pairs of both sexes reared together, the present study examined the extent to which the variance in smoking involvement is attributable to genetic and environmental effects, and to what extent there are sex differences in the etiology. Questionnaire data on how often the adolescent had ever smoked tobacco was collected from a population-based twin sample consisting of seven national birth cohorts (ages 12-18), their mothers, and their fathers (N = 1,394 families). The data was analyzed with multivariate genetic modeling, using a multi-informant design. The etiological structure of smoking involvement was best represented in an ACE common pathway model, with smoking defined as a latent factor loading onto all three informants' reports. Estimates could be set equal across sexes. Results showed that adolescent lifetime smoking involvement was moderately heritable (37 %). The largest influence was from the shared environment (56 %), while environmental effects unique to each twin had minimal influence (7 %).

  4. Heredity and Environment in Etiology of Eating Disorders. I. Review of Twin Studies

    Directory of Open Access Journals (Sweden)

    Meshkova T.A.

    2015-06-01

    Full Text Available Twin studies of eating disorders (anorexia nervosa, bulimia nervosa, and binge eating are reviewed. Historically, eating disorders (ED was viewed as a disorders primarily influenced by sociocultural factors, however, over the past decade, this perception has been challenged. Twin studies demonstrate that genetic factors significantly influence the risk for ED and substantially contribute to the observed association between ED and other disorders and personal traits (major depression, anxiety disorders, substance use disorders, perfectionism. Among environmental factors nonshared (unique environment plays the main role, except of early puberty.

  5. Diprosopus conjoined twins: radiologic, autoptic, and histologic study of a case.

    Science.gov (United States)

    D'Armiento, Maria; Falleti, Jessica; Maruotti, Giuseppe Maria; Martinelli, Pasquale

    2010-01-01

    Conjoined twins are a rare and intriguing nature's phenomena; diprosopus or craniofacial duplication is the rarest with a reported incidence of 1 case in 180,000-15 million births. We present a radiologic, autoptic, and histologic study of a 37-week-old male diprosopus twin in a dichorionic pregnancy of a 26-old-year woman. Diprosopus malformation is part of duplication involving face and cranium like janiceps and dicephalus. Our case also shows partial duplication of the stomach with ectopic pancreas. Most studies are required to understand the exact mechanism of this malformation.

  6. Twin study of heritability of eating bread in Danish and Finnish men and women

    DEFF Research Database (Denmark)

    Hasselbalch, Ann Louise; Silventoinen, Karri; Keskitalo, Kaisu

    2010-01-01

    Bread is an elementary part of the western diet, and especially rye bread is regarded as an important source of fibre. We investigated the heritability of eating bread in terms of choice of white and rye bread and use-frequency of bread in female and male twins in Denmark and Finland. The study...... cohorts included 575 Danish (age range 18-67 years) and 2009 Finnish (age range 22-27 years) adult twin pairs. Self-reported frequency of eating bread was obtained by food frequency questionnaires. Univariate models based on linear structural equations for twin data were used to estimate the relative...... magnitude of the additive genetic, shared environmental and individual environmental effects on bread eating frequency and choice of bread. The analysis of bread intake frequency demonstrated moderate heritability ranging from 37-40% in the Finnish cohort and 23-26% in the Danish cohort. The genetic...

  7. Heritability of myopia and ocular biometrics in Koreans: the healthy twin study.

    Science.gov (United States)

    Kim, Myung Hun; Zhao, Di; Kim, Woori; Lim, Dong-Hui; Song, Yun-Mi; Guallar, Eliseo; Cho, Juhee; Sung, Joohon; Chung, Eui-Sang; Chung, Tae-Young

    2013-05-01

    To estimate the heritabilities of myopia and ocular biometrics among different family types among a Korean population. We studied 1508 adults in the Healthy Twin Study. Spherical equivalent, axial length, anterior chamber depth, and corneal astigmatism were measured by refraction, corneal topography, and A-scan ultrasonography. To see the degree of resemblance among different types of family relationships, intraclass correlation coefficients (ICC) were calculated. Variance-component methods were applied to estimate the genetic contributions to eye phenotypes as heritability based on the maximum likelihood estimation. Narrow sense heritability was calculated as the proportion of the total phenotypic variance explained by additive genetic effects, and linear and nonlinear effects of age, sex, and interactions between age and sex were adjusted. A total of 240 monozygotic twin pairs, 45 dizygotic twin pairs, and 938 singleton adult family members who were first-degree relatives of twins in 345 families were included in the study. ICCs for spherical equivalent from monozygotic twins, pooled first-degree pairs, and spouse pairs were 0.83, 0.34, and 0.20, respectively. The ICCs of other ocular biometrics were also significantly higher in monozygotic twins compared with other relative pairs, with greater consistency and conformity. The estimated narrow sense heritability (95% confidence interval) was 0.78 (0.71-0.84) for spherical equivalent; 0.86 (0.82-0.90) for axial length; 0.83 (0.76-0.91) for anterior chamber depth; and 0.70 (0.63-0.77) for corneal astigmatism. The estimated heritability of spherical equivalent and ocular biometrics in the Korean population suggests the compelling evidence that all traits are highly heritable.

  8. Long-term leisure time physical activity and properties of bone: a twin study.

    Science.gov (United States)

    Ma, Hongqiang; Leskinen, Tuija; Alen, Markku; Cheng, Sulin; Sipilä, Sarianna; Heinonen, Ari; Kaprio, Jaakko; Suominen, Harri; Kujala, Urho M

    2009-08-01

    Effects of physical activity on bone properties, when controlled for genetic effects, are not fully understood. We aimed to study the association between long-term leisure time physical activity (LTPA) and bone properties using twin pairs known to be discordant for leisure time physical activity for at least 30 yr. Volumetric BMD and geometric properties were measured at the tibia shaft and distal end using pQCT in 16 middle-aged (50-74 yr) same-sex twin pairs (seven monozygotic [MZ] and nine dizygotic [DZ] pairs) selected from a population-based cohort. Paired differences between active and inactive co-twins were studied. Active members of MZ twin pairs had larger cortical bone cross-sectional area (intrapair difference: 8%, p = 0.006), thicker cortex (12%, p = 0.003), and greater moment of inertia (I(max), 20%, p = 0.024) at the tibia shaft than their inactive co-twins. At the distal tibia, trabecular BMD (12%, p = 0.050) and compressive strength index (18%, p = 0.038) were also higher in physically active MZ pair members than their inactive co-twins. The trends were similar, but less consistently so, in DZ pairs as in MZ pairs. Our genetically controlled study design shows that LTPA during adulthood strengthens bones in a site-specific manner, that is, the long bone shaft has a thicker cortex, and thus higher bending strength, whereas the distal bone has higher trabecular density and compressive strength. These results suggest that LTPA has a potential causal role in decreasing the long-term risk of osteoporosis and thus preventing osteoporotic fractures.

  9. Twin-singleton differences in intelligence: a register-based birth cohort study of Norwegian males.

    Science.gov (United States)

    Eriksen, Willy; Sundet, Jon M; Tambs, Kristian

    2012-10-01

    The aim was to determine the difference in intelligence between singletons and twins in young adulthood. Data from the Medical Birth Register of Norway were linked with register data from the Norwegian National Conscript Service. The study base consisted of data on the 445,463 males who were born alive in either single or twin births in Norway during 1967-1984 and who were examined at the time of the mandatory military conscription (age 18-20). Within this study base, there were data on 1,653 sibships of full brothers that included at least one man born in single birth and at least one man born in twin birth (4,307 persons, including 2,378 twins and 1,929 singletons). The intelligence scores of the singletons were 11% (95% confidence interval [CI]: 9-14%) of a standard deviation higher than those of the twins, after adjustment for birth year, birth order, parental ages at delivery, parental education levels, and other factors. The adjusted within-family difference was also 11% (95 % CI: 6-16%) of a standard deviation, indicating that unmeasured factors shared by siblings (e.g., maternal body height) have not influenced the estimate in important ways. When gestational age at birth was added to the model, the estimate for the difference in intelligence score was approximately the same. Including birth weight in the model strongly reduced the estimate. In conclusion, twins born in Norway during 1967-1984 had slightly lower intelligence in early adulthood compared with the singletons.

  10. Study on Brazil law type twinning in amethyst from Bahia (Brazil) by the X-ray topography and polarized light

    International Nuclear Information System (INIS)

    Baran, Z.

    1987-01-01

    Brazil law type twinning is very common in quartz. Generally is not observed in normal petrographic thin section but it is possible to study this kind of twinning under polarized light in thicker sections. X-ray topography will be another powerfull method to study and it was applied for the amethytst of the Mina Cabeluda of the state of Bahia. (author) [pt

  11. Genetic architecture of motives for leisure-time physical activity : a twin study

    NARCIS (Netherlands)

    Aaltonen, S.; Kaprio, J.; Vuoksimaa, E.; Huppertz, C.; Kujala, U. M.; Silventoinen, K.

    2017-01-01

    The aim of this study was to estimate the contribution of genetic and environmental influences on motives for engaging in leisure-time physical activity. The participants were obtained from the FinnTwin16 study. A modified version of the Recreational Exercise Motivation Measure was used to assess

  12. Evidence for shared genetic risk between ADHD symptoms and reduced mathematics ability: a twin study.

    Science.gov (United States)

    Greven, Corina U; Kovas, Yulia; Willcutt, Erik G; Petrill, Stephen A; Plomin, Robert

    2014-01-01

    Attention-deficit/hyperactivity disorder (ADHD) symptoms and mathematics ability are associated, but little is known about the genetic and environmental influences underlying this association. Data came from more than 6,000 twelve-year-old twin pairs from the UK population-representative Twins Early Development Study. Parents rated each twin's behaviour using a DSM-IV-based 18-item questionnaire of inattentive and hyperactive-impulsive ADHD symptoms. Mathematics tests based on the UK National Curriculum were completed by each twin. The twins also completed standardised tests of reading and general cognitive ability. Multivariate twin model fitting was applied. Inattentive and hyperactive-impulsive ADHD symptoms were highly heritable (67% and 73% respectively). Mathematics ability was moderately heritable (46%). Mathematics ability and inattentiveness showed a significantly greater phenotypic correlation (r(p) = -.26) and genetic correlation (r(A) = -.41) than mathematics ability and hyperactivity-impulsivity (r(p) = -.18; r(A) = -.22). The genetic correlation between inattentiveness and mathematics ability was largely independent from hyperactivity-impulsivity, and was only partially accounted for by genetic influences related to reading and general cognitive ability. Results revealed the novel finding that mathematics ability shows significantly stronger phenotypic and genetic associations with inattentiveness than with hyperactivity-impulsivity. Genetic associations between inattentiveness and mathematics ability could only partially be accounted for by hyperactivity-impulsivity, reading and general cognitive ability. Results suggest that mathematics ability is associated with ADHD symptoms largely because it shares genetic risk factors with inattentiveness, and provide further evidence for considering inattentiveness and hyperactivity-impulsivity separately. DNA markers for ADHD symptoms (especially inattentiveness) may also be candidate risk factors for

  13. Exploring Anxiety Symptoms in a Large-Scale Twin Study of Children with Autism Spectrum Disorders, Their Co-Twins and Controls

    Science.gov (United States)

    Hallett, Victoria; Ronald, Angelica; Colvert, Emma; Ames, Catherine; Woodhouse, Emma; Lietz, Stephanie; Garnett, Tracy; Gillan, Nicola; Rijsdijk, Fruhling; Scahill, Lawrence; Bolton, Patrick; Happé, Francesca

    2013-01-01

    Background: Although many children with autism spectrum disorders (ASDs) experience difficulties with anxiety, the manifestation of these difficulties remains unresolved. The current study assessed anxiety in a large population-based twin sample, aged 10-15 years. Phenotypic analyses were used to explore anxiety symptoms in children with ASDs,…

  14. Infant twin mortality and hospitalisations after the perinatal period - a prospective cohort study from Guinea-Bissau

    DEFF Research Database (Denmark)

    Bjerregaard-Andersen, M; Biering-Sørensen, S; Gomes, G M

    2014-01-01

    OBJECTIVE: To examine mortality and hospitalisations among infant twins and singletons after the perinatal period in Guinea-Bissau. METHODS: The study was conducted from September 2009 to November 2012 by the Bandim Health Project (BHP). Newborn twins and unmatched singleton controls were included...

  15. Measuring adolescents’ exposure to victimization: The Environmental Risk (E-Risk) Longitudinal Twin Study

    Science.gov (United States)

    Fisher, Helen L.; Caspi, Avshalom; Moffitt, Terrie E.; Wertz, Jasmin; Gray, Rebecca; Newbury, Joanne; Ambler, Antony; Zavos, Helena; Danese, Andrea; Mill, Jonathan; Odgers, Candice L.; Pariante, Carmine; Wong, Chloe C.; Arseneault, Louise

    2016-01-01

    This paper presents mutlilevel findings on adolescents’ victimization exposure from a large longitudinal cohort of twins. Data were obtained from the Environmental Risk (E-Risk) Longitudinal Twin Study, an epidemiological study of 2,232 children (1,116 twin pairs) followed to 18 years of age (with 93% retention). To assess adolescent victimization we combined best practices in survey research on victimization with optimal approaches to measuring life stress and traumatic experiences, and introduce a reliable system for coding severe victimization. One in three children experienced at least one type of severe victimization during adolescence (crime victimization, peer/sibling victimization, internet/mobile phone victimization, sexual victimization, family violence, maltreatment, or neglect), and most types of victimization were more prevalent amongst children from low socioeconomic backgrounds. Exposure to multiple victimization types was common, as was re-victimization; over half of those physically maltreated in childhood were also exposed to severe physical violence in adolescence. Biometric twin analyses revealed that environmental factors had the greatest influence on most types of victimization, while severe physical maltreatment from caregivers during adolescence was predominantly influenced by heritable factors. The findings from this study showcase how distinct levels of victimization measurement can be harmonized in large-scale studies of health and development. PMID:26535933

  16. A Twin-Sibling Study on the Relationship Between Exercise Attitudes and Exercise Behavior

    NARCIS (Netherlands)

    Huppertz, C.; Bartels, M.; Jansen, I.E.; Boomsma, D.I.; Willemsen, G.; de Moor, M.H.M.; de Geus, E.J.C.

    2014-01-01

    Social cognitive models of health behavior propose that individual differences in leisure time exercise behavior are influenced by the attitudes towards exercise. At the same time, large scale twin-family studies show a significant influence of genetic factors on regular exercise behavior. This

  17. Aging Trajectories in Different Body Systems Share Common Environmental Etiology : The Healthy Aging Twin Study (HATS)

    NARCIS (Netherlands)

    Moayyeri, Alireza; Hart, Deborah J.; Snieder, Harold; Hammond, Christopher J.; Spector, Timothy D.; Steves, Claire J.

    Little is known about the extent to which aging trajectories of different body systems share common sources of variance. We here present a large twin study investigating the trajectories of change in five systems: cardiovascular, respiratory, skeletal, morphometric, and metabolic. Longitudinal

  18. Breastfeeding, Maternal Education and Cognitive Function: A Prospective Study in Twins

    NARCIS (Netherlands)

    Bartels, M.; van Beijsterveldt, C.E.M.; Boomsma, D.I.

    2009-01-01

    The effect of breastfeeding on cognitive abilities is examined in the offspring of highly educated women and compared to the effects in women with low or middle educational attainment. All offspring consisted of 12-year old mono- or dizygotic twins and this made it possible to study the effect of

  19. A Twin Study of Heritable and Shared Environmental Contributions to Autism

    Science.gov (United States)

    Frazier, Thomas W.; Thompson, Lee; Youngstrom, Eric A.; Law, Paul; Hardan, Antonio Y.; Eng, Charis; Morris, Nathan

    2014-01-01

    The present study examined genetic and shared environment contributions to quantitatively-measured autism symptoms and categorically-defined autism spectrum disorders (ASD). Participants included 568 twins from the Interactive Autism Network. Autism symptoms were obtained using the Social Communication Questionnaire and Social Responsiveness…

  20. DNA methylation age is associated with mortality in a longitudinal Danish twin study

    DEFF Research Database (Denmark)

    Christiansen, Lene; Lenart, Adam; Tan, Qihua

    2016-01-01

    included a 10-year longitudinal study of the 86 oldest-old twins (mean age of 86.1 at follow-up), which subsequently were followed for mortality for 8 years. We found that the DNAm age is highly correlated with chronological age across all age groups (r = 0.97), but that the rate of change of DNAm age...

  1. Improving fluid registration through white matter segmentation in a twin study design

    Science.gov (United States)

    Chou, Yi-Yu; Lepore, Natasha; Brun, Caroline; Barysheva, Marina; McMahon, Katie; de Zubicaray, Greig I.; Wright, Margaret J.; Toga, Arthur W.; Thompson, Paul M.

    2010-03-01

    Robust and automatic non-rigid registration depends on many parameters that have not yet been systematically explored. Here we determined how tissue classification influences non-linear fluid registration of brain MRI. Twin data is ideal for studying this question, as volumetric correlations between corresponding brain regions that are under genetic control should be higher in monozygotic twins (MZ) who share 100% of their genes when compared to dizygotic twins (DZ) who share half their genes on average. When these substructure volumes are quantified using tensor-based morphometry, improved registration can be defined based on which method gives higher MZ twin correlations when compared to DZs, as registration errors tend to deplete these correlations. In a study of 92 subjects, higher effect sizes were found in cumulative distribution functions derived from statistical maps when performing tissue classification before fluid registration, versus fluidly registering the raw images. This gives empirical evidence in favor of pre-segmenting images for tensor-based morphometry.

  2. Sex differences in jealousy: a population-based twin study in Sweden.

    Science.gov (United States)

    Walum, Hasse; Larsson, Henrik; Westberg, Lars; Lichtenstein, Paul; Magnusson, Patrik K E

    2013-10-01

    According to the theory of evolved sex differences in jealousy, the challenge for women to ensure paternal investment increased their jealousy response to emotional infidelity, whereas paternal uncertainty exerted selective pressures that shaped men to become more distressed by sexual infidelity. Several studies have investigated whether the effect of these sexually dimorphic selection pressures can be detected in contemporary human populations, with conflicting results. To date, no genetically informed studies of sex differences in jealousy have been conducted. We used data from the Screening Across the Lifespan of Twins Younger (SALTY) sample, containing information concerning self-rated jealousy from 3,197 complete twin pairs collected by the Swedish Twin Registry. Intra-class correlations and structural equation models were used to assess the genetic influence on jealousy and to investigate sex differences at genetic level. We saw a highly significant sex effect on the relationship between infidelity types, indicating that men, relative to women, reported greater jealousy in response to sexual infidelity than in response to emotional infidelity. The twin models revealed significant heritabilities for both sexual (32%) and emotional (26%) jealousy. The heritabilities were of a similar magnitude in both sexes, and no qualitative sex differences could be detected. We show for the first time that variance in jealousy is to some extent explained by genetic factors. Even though our results from the mean value analyses are in line with the theory of evolved sex differences in jealousy, we could not identify any sex differences on a genetic level.

  3. Nineteen and Up study (19Up): understanding pathways to mental health disorders in young Australian twins.

    Science.gov (United States)

    Couvy-Duchesne, Baptiste; O'Callaghan, Victoria; Parker, Richard; Mills, Natalie; Kirk, Katherine M; Scott, Jan; Vinkhuyzen, Anna; Hermens, Daniel F; Lind, Penelope A; Davenport, Tracey A; Burns, Jane M; Connell, Melissa; Zietsch, Brendan P; Scott, James; Wright, Margaret J; Medland, Sarah E; McGrath, John; Martin, Nicholas G; Hickie, Ian B; Gillespie, Nathan A

    2018-03-17

    The Nineteen and Up study (19Up) assessed a range of mental health and behavioural problems and associated risk factors in a genetically informative Australian cohort of young adult twins and their non-twin siblings. As such, 19Up enables detailed investigation of genetic and environmental pathways to mental illness and substance misuse within the Brisbane Longitudinal Twin Sample (BLTS). Twins and their non-twin siblings from Queensland, Australia; mostly from European ancestry. Data were collected between 2009 and 2016 on 2773 participants (age range 18-38, 57.8% female, 372 complete monozygotic pairs, 493 dizygotic pairs, 640 non-twin siblings, 403 singleton twins). A structured clinical assessment (Composite International Diagnostic Interview) was used to collect lifetime prevalence of diagnostic statistical manual (4th edition) (DSM-IV) diagnoses of major depressive disorder, (hypo)mania, social anxiety, cannabis use disorder, alcohol use disorder, panic disorder and psychotic symptoms. Here, we further describe the comorbidities and ages of onset for these mental disorders. Notably, two-thirds of the sample reported one or more lifetime mental disorder.In addition, the 19Up study assessed general health, drug use, work activity, education level, personality, migraine/headaches, suicidal thoughts, attention deficit hyperactivity disorder (ADHD) symptomatology, sleep-wake patterns, romantic preferences, friendships, familial environment, stress, anorexia and bulimia as well as baldness, acne, asthma, endometriosis, joint flexibility and internet use.The overlap with previous waves of the BLTS means that 84% of the 19Up participants are genotyped, 36% imaged using multimodal MRI and most have been assessed for psychological symptoms at up to four time points. Furthermore, IQ is available for 57%, parental report of ADHD symptomatology for 100% and electroencephalography for 30%. The 19Up study complements a phenotypically rich, longitudinal collection of

  4. Twin Birth Study: 2-year neurodevelopmental follow-up of the randomized trial of planned cesarean or planned vaginal delivery for twin pregnancy.

    Science.gov (United States)

    Asztalos, Elizabeth V; Hannah, Mary E; Hutton, Eileen K; Willan, Andrew R; Allen, Alexander C; Armson, B Anthony; Gafni, Amiram; Joseph, K S; Ohlsson, Arne; Ross, Susan; Sanchez, J Johanna; Mangoff, Kathryn; Barrett, Jon F R

    2016-03-01

    The Twin Birth Study randomized women with uncomplicated pregnancies, between 32(0/7)-38(6/7) weeks' gestation where the first twin was in cephalic presentation, to a policy of either a planned cesarean or planned vaginal delivery. The primary analysis showed that planned cesarean delivery did not increase or decrease the risk of fetal/neonatal death or serious neonatal morbidity as compared with planned vaginal delivery. This study presents the secondary outcome of death or neurodevelopmental delay at 2 years of age. A total of 4603 children from the initial cohort of 5565 fetuses/infants (83%) contributed to the outcome of death or neurodevelopmental delay. Surviving children were screened using the Ages and Stages Questionnaire with abnormal scores validated by a clinical neurodevelopmental assessment. The effect of planned cesarean vs planned vaginal delivery on death or neurodevelopmental delay was quantified using a logistic model to control for stratification variables and using generalized estimating equations to account for the nonindependence of twin births. Baseline maternal, pregnancy, and infant characteristics were similar. Mean age at assessment was 26 months. There was no significant difference in the outcome of death or neurodevelopmental delay: 5.99% in the planned cesarean vs 5.83% in the planned vaginal delivery group (odds ratio, 1.04; 95% confidence interval, 0.77-1.41; P = .79). A policy of planned cesarean delivery provides no benefit to children at 2 years of age compared with a policy of planned vaginal delivery in uncomplicated twin pregnancies between 32(0/7)-38(6/7)weeks' gestation where the first twin is in cephalic presentation. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Risks of neurological and immune-related diseases, including narcolepsy, after vaccination with Pandemrix: a population- and registry-based cohort study with over 2 years of follow-up.

    Science.gov (United States)

    Persson, I; Granath, F; Askling, J; Ludvigsson, J F; Olsson, T; Feltelius, N

    2014-02-01

    To investigate the association between vaccination with Pandemrix and risk of selected neurological and immune-related diseases including narcolepsy. Population-based prospective cohort study using data from regional vaccination registries and national health registries. Seven healthcare regions in Sweden comprising 61% of the Swedish population. Study population of 3,347,467 vaccinated and 2,497,572 nonvaccinated individuals (vaccination coverage ≈ 60%) followed between 2009 and 2011 for 6.9 million person-years after exposure and 6.0 million person-years without exposure. First recorded diagnosis of neurological and immune-related diseases. Relative risks [hazard ratios (HRs) with 95% confidence intervals (CIs)] assessed using Cox regression, adjusted for covariates. For all selected neurological and immune-related outcomes under study, other than allergic vaccine reactions (for which we verified an expected increase in risk) and narcolepsy, HRs were close to 1.0 and always below 1.3. We observed a three-fold increased risk of a diagnosis of narcolepsy (HR: 2.92, 95% CI: 1.78-4.79; that is, four additional cases per 100,000 person-years) in individuals ≤ 20 years of age at vaccination and a two-fold increase (HR: 2.18, 95% CI: 1.00-4.75) amongst young adults between 21 and 30 years of age. The excess risk declined successively with increasing age at vaccination; no increase in risk was seen after 40 years of age. For a large number of selected neurological and immune-related diseases, we could neither confirm any causal association with Pandemrix nor refute entirely a small excess risk. We confirmed an increased risk for a diagnosis of narcolepsy in individuals ≤ 20 years of age and observed a trend towards an increased risk also amongst young adults between 21 and 30 years. © 2013 The Association for the Publication of the Journal of Internal Medicine.

  6. Placental cord insertion and birthweight discordance in twin pregnancies: results of the national prospective ESPRiT Study.

    Science.gov (United States)

    Kent, Etaoin M; Breathnach, Fionnuala M; Gillan, John E; McAuliffe, Fionnuala M; Geary, Michael P; Daly, Sean; Higgins, John R; Dornan, James; Morrison, John J; Burke, Gerard; Higgins, Shane; Carroll, Stephen; Dicker, Patrick; Manning, Fiona; Malone, Fergal D

    2011-10-01

    The purpose of this study was to evaluate the impact of noncentral placental cord insertion on birthweight discordance in twins. We performed a multicenter, prospective trial of twin pregnancies. Placental cord insertion was documented as central, marginal, or velamentous according to a defined protocol. Association of the placental cord insertion site with chorionicity, birthweight discordance, and growth restriction were assessed. Eight hundred sixteen twin pairs were evaluated; 165 pairs were monochorionic, and 651 pairs were dichorionic. Monochorionic twins had higher rates of marginal (P = .0068) and velamentous (P < .0001) placental cord insertion. Noncentral placental cord insertion was more frequent in smaller twins of discordant pairs than control pairs (29.8% vs 19.1%; P = .004). Velamentous placental cord insertion in monochorionic twins was associated significantly with birthweight discordance (odds ratio, 3.5; 95% confidence interval, 1.3-9.4) and growth restriction (odds ratio, 4; 95% confidence interval, 1.1-14.3). Noncentral placental cord insertion contributes to birthweight discordance in monochorionic twin pregnancies. Sonographic delineation of placental cord insertion may be of value in antenatal assessment of twin pregnancies. Copyright © 2011 Mosby, Inc. All rights reserved.

  7. Comprehensive Analysis of the Incidence and Survival Patterns of Lung Cancer by Histologies, Including Rare Subtypes, in the Era of Molecular Medicine and Targeted Therapy: A Nation-Wide Cancer Registry-Based Study From Taiwan.

    Science.gov (United States)

    Chang, Jeffrey S; Chen, Li-Tzong; Shan, Yan-Shen; Lin, Sheng-Fung; Hsiao, Sheng-Yen; Tsai, Chia-Rung; Yu, Shu-Jung; Tsai, Hui-Jen

    2015-06-01

    Lung cancer is the third most common cancer in the world and has the highest cancer mortality rate. A worldwide increasing trend of lung adenocarcinoma has been noted. In addition, the identification of epidermal growth factor receptor (EGFR) mutations and the introduction of EGFR inhibitors to successfully treat EGFR mutated non-small cell lung cancers are breakthroughs for lung cancer treatment. The current study evaluated the incidence and survival of lung cancer using data collected by the Taiwan Cancer Registry between 1996 and 2008. The results showed that the most common histologic subtype of lung cancer was adenocarcinoma, followed by squamous cell carcinoma, small cell carcinoma, large cell carcinoma, neuroendocrine tumors, lymphoma, and sarcoma. Overall, the incidence of lung cancer in Taiwan increased significantly from 1996 to 2008. An increased incidence was observed for adenocarcinoma, particularly for women, with an annual percentage change of 5.9, whereas the incidence of squamous cell carcinoma decreased. Among the subtypes of lung cancer, the most rapid increase occurred in neuroendocrine tumors with an annual percentage change of 15.5. From 1996-1999 to 2005-2008, the 1-year survival of adenocarcinoma increased by 10% for men, whereas the 1-, 3-, and 5-year survivals of adenocarcinoma for women increased by 18%, 11%, and 5%, respectively. Overall, the incidence of lung cancer has been increasing in Taiwan, although the trends were variable by subtype. The introduction of targeted therapies was associated with a significantly improved survival for lung adenocarcinoma in Taiwan; however, more studies are needed to explain the rising incidence of lung adenocarcinoma. In addition, it is important to investigate the molecular pathogenesis of the various subtypes of lung cancer to develop novel therapeutic agents.

  8. Determination of the Oswestry Disability Index score equivalent to a "satisfactory symptom state" in patients undergoing surgery for degenerative disorders of the lumbar spine-a Spine Tango registry-based study.

    Science.gov (United States)

    van Hooff, Miranda L; Mannion, Anne F; Staub, Lukas P; Ostelo, Raymond W J G; Fairbank, Jeremy C T

    2016-10-01

    The achievement of a given change score on a valid outcome instrument is commonly used to indicate whether a clinically relevant change has occurred after spine surgery. However, the achievement of such a change score can be dependent on baseline values and does not necessarily indicate whether the patient is satisfied with the current state. The achievement of an absolute score equivalent to a patient acceptable symptom state (PASS) may be a more stringent measure to indicate treatment success. This study aimed to estimate the score on the Oswestry Disability Index (ODI, version 2.1a; 0-100) corresponding to a PASS in patients who had undergone surgery for degenerative disorders of the lumbar spine. This is a cross-sectional study of diagnostic accuracy using follow-up data from an international spine surgery registry. The sample includes 1,288 patients with degenerative lumbar spine disorders who had undergone elective spine surgery, registered in the EUROSPINE Spine Tango Spine Surgery Registry. The main outcome measure was the ODI (version 2.1a). Surgical data and data from the ODI and Core Outcome Measures Index (COMI) were included to determine the ODI threshold equivalent to PASS at 1 year (±1.5 months; n=780) and 2 years (±2 months; n=508) postoperatively. The symptom-specific well-being item of the COMI was used as the external criterion in the receiver operating characteristic (ROC) analysis to determine the ODI threshold equivalent to PASS. Separate sensitivity analyses were performed based on the different definitions of an "acceptable state" and for subgroups of patients. JF is a copyright holder of the ODI. The ODI threshold for PASS was 22, irrespective of the time of follow-up (area under the curve [AUC]: 0.89 [sensitivity {Se}: 78.3%, specificity {Sp}: 82.1%] and AUC: 0.91 [Se: 80.7%, Sp: 85.6] for the 1- and 2-year follow-ups, respectively). Sensitivity analyses showed that the absolute ODI-22 threshold for the two follow-up time-points were

  9. Use of a geographic information system to identify differences in automated external defibrillator installation in urban areas with similar incidence of public out-of-hospital cardiac arrest: a retrospective registry-based study.

    Science.gov (United States)

    Fredman, David; Haas, Jan; Ban, Yifang; Jonsson, Martin; Svensson, Leif; Djarv, Therese; Hollenberg, Jacob; Nordberg, Per; Ringh, Mattias; Claesson, Andreas

    2017-06-02

    Early defibrillation in out-of-hospital cardiac arrest (OHCA) is of importance to improve survival. In many countries the number of automated external defibrillators (AEDs) is increasing, but the use is low. Guidelines suggest that AEDs should be installed in densely populated areas and in locations with many visitors. Attempts have been made to identify optimal AED locations based on the incidence of OHCA using geographical information systems (GIS), but often on small datasets and the studies are seldom reproduced. The aim of this paper is to investigate if the distribution of public AEDs follows the incident locations of public OHCAs in urban areas of Stockholm County, Sweden. OHCA data were obtained from the Swedish Register for Cardiopulmonary Resuscitation and AED data were obtained from the Swedish AED Register. Urban areas in Stockholm County were objectively classified according to the pan-European digital mapping tool, Urban Atlas (UA). Furthermore, we reclassified and divided the UA land cover data into three classes (residential, non-residential and other areas). GIS software was used to spatially join and relate public AED and OHCA data and perform computations on relations and distance. Between 1 January 2012 and 31 December 2014 a total of 804 OHCAs occurred in public locations in Stockholm County and by December 2013 there were 1828 AEDs available. The incidence of public OHCAs was similar in residential (47.3%) and non-residential areas (43.4%). Fewer AEDs were present in residential areas than in non-residential areas (29.4% vs 68.8%). In residential areas the median distance between OHCAs and AEDs was significantly greater than in non-residential areas (288 m vs 188 m, p<0.001). The majority of public OHCAs occurred in areas classified in UA as 'residential areas' with limited AED accessibility. These areas need to be targeted for AED installation and international guidelines need to take geographical location into account when suggesting

  10. A twin-sibling study on the relationship between exercise attitudes and exercise behavior.

    Science.gov (United States)

    Huppertz, Charlotte; Bartels, Meike; Jansen, Iris E; Boomsma, Dorret I; Willemsen, Gonneke; de Moor, Marleen H M; de Geus, Eco J C

    2014-01-01

    Social cognitive models of health behavior propose that individual differences in leisure time exercise behavior are influenced by the attitudes towards exercise. At the same time, large scale twin-family studies show a significant influence of genetic factors on regular exercise behavior. This twin-sibling study aimed to unite these findings by demonstrating that exercise attitudes can be heritable themselves. Secondly, the genetic and environmental cross-trait correlations and the monozygotic (MZ) twin intrapair differences model were used to test whether the association between exercise attitudes and exercise behavior can be causal. Survey data were obtained from 5,095 twins and siblings (18-50 years). A genetic contribution was found for exercise behavior (50 % in males, 43 % in females) and for the six exercise attitude components derived from principal component analysis: perceived benefits (21, 27 %), lack of skills, support and/or resources (45, 48 %), time constraints (25, 30 %), lack of energy (34, 44 %), lack of enjoyment (47, 44 %), and embarrassment (42, 49 %). These components were predictive of leisure time exercise behavior (R(2) = 28 %). Bivariate modeling further showed that all the genetic (0.36 exercise attitudes and exercise behavior were significantly different from zero, which is a necessary condition for the existence of a causal effect driving the association. The correlations between the MZ twins' difference scores were in line with this finding. It is concluded that exercise attitudes and exercise behavior are heritable, that attitudes and behavior are partly correlated through pleiotropic genetic effects, but that the data are compatible with a causal association between exercise attitudes and behavior.

  11. A twin study of early-childhood asthma in Puerto Ricans.

    Directory of Open Access Journals (Sweden)

    Supinda Bunyavanich

    Full Text Available The relative contributions of genetics and environment to asthma in Hispanics or to asthma in children younger than 3 years are not well understood.To examine the relative contributions of genetics and environment to early-childhood asthma by performing a longitudinal twin study of asthma in Puerto Rican children ≤ 3 years old.678 twin infants from the Puerto Rico Neo-Natal Twin Registry were assessed for asthma at age 1 year, with follow-up data obtained for 624 twins at age 3 years. Zygosity was determined by DNA microsatellite profiling. Structural equation modeling was performed for three phenotypes at ages 1 and 3 years: physician-diagnosed asthma, asthma medication use in the past year, and ≥ 1 hospitalization for asthma in the past year. Models were additionally adjusted for early-life environmental tobacco smoke exposure, sex, and age.The prevalences of physician-diagnosed asthma, asthma medication use, and hospitalization for asthma were 11.6%, 10.8%, 4.9% at age 1 year, and 34.1%, 40.1%, and 8.5% at 3 years, respectively. Shared environmental effects contributed to the majority of variance in susceptibility to physician-diagnosed asthma and asthma medication use in the first year of life (84%-86%, while genetic effects drove variance in all phenotypes (45%-65% at age 3 years. Early-life environmental tobacco smoke, sex, and age contributed to variance in susceptibility.Our longitudinal study in Puerto Rican twins demonstrates a changing contribution of shared environmental effects to liability for physician-diagnosed asthma and asthma medication use between ages 1 and 3 years. Early-life environmental tobacco smoke reduction could markedly reduce asthma morbidity in young Puerto Rican children.

  12. Alanine aminotransferase, gamma-glutamyltransferase (GGT) and all-cause mortality: results from a population-based Danish twins study alanine aminotransferase, GGT and mortality in elderly twins

    DEFF Research Database (Denmark)

    Fraser, Abigail; Thinggaard, Mikael; Christensen, Kaare

    2009-01-01

    Abstract Background/Aims: Alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT) are widely used markers of liver disease. Several population-based cohort studies have found associations of these liver enzymes with all-cause mortality. None of these studies controlled for genetic...... for potential confounders and existing diabetes and cardiovascular disease. Environmental developmental origins may explain the association, but larger twin studies are required to replicate our findings....

  13. Excess Mortality in Patients Diagnosed With Hypothyroidism: A Nationwide Cohort Study of Singletons and Twins

    Science.gov (United States)

    Thvilum, Marianne; Brandt, Frans; Almind, Dorthe; Christensen, Kaare; Brix, Thomas Heiberg

    2013-01-01

    Background: Although hypothyroidism is associated with increased morbidity, an association with increased mortality is still debated. Our objective was to investigate, at a nationwide level, whether a diagnosis of hypothyroidism influences mortality. Methods: In an observational cohort study from January 1, 1978 until December 31, 2008 using record-linkage data from nationwide Danish health registers, 3587 singletons and 682 twins diagnosed with hypothyroidism were identified. Hypothyroid individuals were matched 1:4 with nonhypothyroid controls with respect to age and gender and followed over a mean period of 5.6 years (range 0–30 years). The hazard ratio (HR) for mortality was calculated using Cox regression analyses. Comorbidity was evaluated using the Charlson score (CS). Results: In singletons with hypothyroidism, the mortality risk was increased (HR 1.52; 95% confidence interval [CI]: 1.41–1.65). Although the effect attenuated, hypothyroidism remained associated with increased mortality when evaluating subjects with a CS = 0 (HR 1.23; 95% CI: 1.05–1.44). In twin pairs discordant for hypothyroidism, the hypothyroid twin had excess mortality compared with the corresponding euthyroid cotwin (HR 1.40; 95% CI 0.95–2.05). However, after stratifying for zygosity, hypothyroidism was associated with excess mortality in dizygotic twin pairs (HR 1.61; 95% CI 1.00–2.58), whereas the association attenuated in monozygotic pairs (HR 1.06; 95% CI 0.55–2.05). Conclusions: Hypothyroidism is associated with an excess mortality of around 50%, which to some degree is explained by comorbidity. In addition, the finding of an association between hypothyroidism and mortality within disease discordant dizygotic but not monozygotic twin pairs indicates that the association between hypothyroidism and mortality is also influenced by genetic confounding. PMID:23365121

  14. Holt Oram syndrome : a registry-based study in Europe

    NARCIS (Netherlands)

    Barisic, Ingeborg; Boban, Ljubica; Greenlees, Ruth; Garne, Ester; Wellesley, Diana; Calzolari, Elisa; Addor, Marie-Claude; Arriola, Larraitz; Bergman, Jorieke E. H.; Braz, Paula; Budd, Judith L. S.; Gatt, Miriam; Haeusler, Martin; Khoshnood, Babak; Klungsoyr, Kari; McDonnell, Bob; Nelen, Vera; Pierini, Anna; Queisser-Wahrendorf, Annette; Rankin, Judith; Rissmann, Anke; Rounding, Catherine; Tucker, David; Verellen-Dumoulin, Christine; Dolk, Helen

    2014-01-01

    Background: Holt-Oram syndrome (HOS) is an autosomal dominant disorder characterised by upper limb anomalies and congenital heart defects. We present epidemiological and clinical aspects of HOS patients using data from EUROCAT (European Surveillance of Congenital Anomalies) registries. Methods: The

  15. Holt Oram syndrome: a registry-based study in Europe

    DEFF Research Database (Denmark)

    Barisic, Ingeborg; Boban, Ljubica; Greenlees, Ruth

    2014-01-01

    were reported in all cases. Agenesis/hypoplasia of radius was present in 49.2% (30/61), ulnar aplasia/hypoplasia in 24.6% (15/61) and humerus hypoplasia/phocomelia in 42.6% (26/61) of patients. Congenital heart defects (CHD) were recorded in 78.7% (48/61) of patients. Isolated septal defects were...

  16. Investigating Unique Environmental Influences of Parenting Practices on Youth Anxiety: A Monozygotic Twin Differences Study

    Science.gov (United States)

    Chen, Jie; Yu, Jing; Zhang, Jianxin

    2016-01-01

    The associations between parenting practices and adolescent anxiety symptoms were examined in both individual and monozygotic (MZ) twin differences levels. Participants were 804 pairs of Chinese MZ adolescent twins aged 10-18 years (M = 13.57, SD = 2.67, 52% females). Twins' anxiety symptoms were assessed by self- and parent-reports. Twins also…

  17. [Adult twins].

    Science.gov (United States)

    Charlemaine, Christiane

    2006-12-31

    This paper explores the deep roots of closeness that twins share in their youngest age and their effect on their destiny at the adult age. Psychologists believe the bond between twins begins in utero and develops throughout the twins' lives. The four patterns of twinship described show that the twin bond is determined by the quality of parenting that twins receive in their infancy and early childhood. Common problems of adult twins bring about difficulties to adapt in a non-twin world. The nature versus nurture controversy has taken on new life focusing on inter-twin differences and the importance of parent-child interaction as fundamental to the growth and development of personality.

  18. Twin RSA

    OpenAIRE

    Lenstra, Arjen K.; Weger, De; Benjamin, M. M.

    2005-01-01

    We introduce Twin RSA, pairs of RSA moduli (n, n+ 2), and formulate several questions related to it. Our main questions are: is Twin RSA secure, and what is it good for? © Springer-Verlag Berlin Heidelberg 2005.

  19. Born to Lead? A Twin Design and Genetic Association Study of Leadership Role Occupancy*

    Science.gov (United States)

    De Neve, Jan-Emmanuel; Mikhaylov, Slava; Dawes, Christopher T.; Christakis, Nicholas A.; Fowler, James H.

    2013-01-01

    We address leadership emergence and the possibility that there is a partially innate predisposition to occupy a leadership role. Employing twin design methods on data from the National Longitudinal Study of Adolescent Health, we estimate the heritability of leadership role occupancy at 24%. Twin studies do not point to specific genes or neurological processes that might be involved. We therefore also conduct association analysis on the available genetic markers. The results show that leadership role occupancy is associated with rs4950, a single nucleotide polymorphism (SNP) residing on a neuronal acetylcholine receptor gene (CHRNB3). We replicate this family-based genetic association result on an independent sample in the Framingham Heart Study. This is the first study to identify a specific genotype associated with the tendency to occupy a leadership position. The results suggest that what determines whether an individual occupies a leadership position is the complex product of genetic and environmental influences; with a particular role for rs4950. PMID:23459689

  20. The Brazilian Twin Registry.

    Science.gov (United States)

    Ferreira, Paulo H; Oliveira, Vinicius C; Junqueira, Daniela R; Cisneros, Lígia C; Ferreira, Lucas C; Murphy, Kate; Ordoñana, Juan R; Hopper, John L; Teixeira-Salmela, Luci F

    2016-12-01

    The Brazilian Twin Registry (BTR) was established in 2013 and has impelled twin research in South America. The main aim of the initiative was to create a resource that would be accessible to the Brazilian scientific community as well as international researchers interested in the investigation of the contribution of genetic and environmental factors in the development of common diseases, phenotypes, and human behavior traits. The BTR is a joint effort between academic and governmental institutions from Brazil and Australia. The collaboration includes the Federal University of Minas Gerais (UFMG) in Brazil, the University of Sydney and University of Melbourne in Australia, the Australian Twin Registry, as well as the research foundations CNPq and CAPES in Brazil. The BTR is a member of the International Network of Twin Registries. Recruitment strategies used to register twins have been through participation in a longitudinal study investigating genetic and environmental factors for low back pain occurrence, and from a variety of sources including media campaigns and social networking. Currently, 291 twins are registered in the BTR, with data on demographics, zygosity, anthropometrics, and health history having been collected from 151 twins using a standardized self-reported questionnaire. Future BTR plans include the registration of thousands of Brazilian twins identified from different sources and collaborate nationally and internationally with other research groups interested on twin studies.

  1. Placental pathology, birthweight discordance, and growth restriction in twin pregnancy: results of the ESPRiT Study.

    Science.gov (United States)

    Kent, Etaoin M; Breathnach, Fionnuala M; Gillan, John E; McAuliffe, Fionnuala M; Geary, Michael P; Daly, Sean; Higgins, John R; Hunter, Alyson; Morrison, John J; Burke, Gerard; Higgins, Shane; Carroll, Stephen; Dicker, Patrick; Manning, Fiona; Tully, Elizabeth; Malone, Fergal D

    2012-09-01

    We sought to evaluate the association between placental histological abnormalities and birthweight discordance and growth restriction in twin pregnancies. We performed a multicenter, prospective study of twin pregnancies. Placentas were examined for evidence of infarction, retroplacental hemorrhage, chorangioma, subchorial fibrin, or abnormal villus maturation. Association of placental lesions with chorionicity, birthweight discordance, and growth restriction were assessed. In all, 668 twin pairs were studied, 21.1% monochorionic and 78.9% dichorionic. Histological abnormalities were more frequent in placentas of smaller twins of birthweight discordant pairs (P = .02) and in placentas of small for gestational age infants (P = .0001) when compared to controls. The association of placental abnormalities with both birthweight discordance and small for gestational age was significant for dichorionic twins (P = .01 and .0001, respectively). No such association was seen in monochorionic twins. In a large, prospective, multicenter study, we observed a strong relationship between abnormalities of placental histology and birthweight discordance and growth restriction in dichorionic, but not monochorionic, twin pregnancies. Copyright © 2012 Mosby, Inc. All rights reserved.

  2. The Heritability of Prostate Cancer in the Nordic Twin Study of Cancer

    DEFF Research Database (Denmark)

    Hjelmborg, Jacob B; Scheike, Thomas; Holst, Klaus

    2014-01-01

    Background: Prostate cancer is thought to be the most heritable cancer, although little is known about how this genetic contribution varies across age. Methods: To address this question, we undertook the world's largest prospective study in the Nordic Twin Study of Cancer cohort, including 18,680....... The role of genetic factors is consistently high across age Impact: Findings impact the search for genetic and epigenetic markers and frame prevention efforts....

  3. A Twin-Sibling Study on the Relationship Between Exercise Attitudes and Exercise Behavior

    OpenAIRE

    Huppertz, Charlotte; Bartels, Meike; Jansen, Iris E.; Boomsma, Dorret I.; Willemsen, Gonneke; de Moor, Marleen H. M.; de Geus, Eco J. C.

    2014-01-01

    Social cognitive models of health behavior propose that individual differences in leisure time exercise behavior are influenced by the attitudes towards exercise. At the same time, large scale twin-family studies show a significant influence of genetic factors on regular exercise behavior. This twin–sibling study aimed to unite these findings by demonstrating that exercise attitudes can be heritable themselves. Secondly, the genetic and environmental cross-trait correlations and the monozygot...

  4. The contribution of twin studies to the understanding of the aetiology of asthma and atopic diseases

    DEFF Research Database (Denmark)

    Thomsen, Simon F

    2015-01-01

    The prevalence of asthma and other atopic diseases has increased markedly during the past decades and the reasons for this are not fully understood. Asthma is still increasing in many parts of the world, notably in developing countries, and this emphasizes the importance of continuing research...... aimed at studying the aetiological factors of the disease and the causes of its increase in prevalence. Twin studies enable investigations into the genetic and environmental causes of individual variation in multifactorial diseases such as asthma. Thorough insight into these causes is important...... as this will ultimately guide the development of preventive strategies and targeted therapies. This review explores the contribution of twin studies to the understanding of the aetiology of asthma and atopic diseases....

  5. A Danish Twin Study of Schizophrenia Liability: Investigation from Interviewed Twins for Genetic Links to Affective Psychoses and for Cross-Cohort Comparisons.

    Science.gov (United States)

    Kläning, Ulla; Trumbetta, Susan L; Gottesman, Irving I; Skytthe, Axel; Kyvik, Kirsten O; Bertelsen, Aksel

    2016-03-01

    We studied schizophrenia liability in a Danish population-based sample of 44 twin pairs (13 MZ, 31 DZ, SS plus OS) in order to replicate previous twin study findings using contemporary diagnostic criteria, to examine genetic liability shared between schizophrenia and other disorders, and to explore whether variance in schizophrenia liability attributable to environmental factors may have decreased with successive cohorts exposed to improvements in public health. ICD-10 diagnoses were determined by clinical interview. Although the best-fitting, most parsimonious biometric model of schizophrenia liability specified variance attributable to additive genetic and non-shared environmental factors, this model did not differ significantly from a model that also included non-additive genetic factors, consistent with recent interview-based twin studies. Schizophrenia showed strong genetic links to other psychotic disorders but much less so for the broader category of psychiatric disorders in general. We also observed a marginally significant decline in schizophrenia variance attributable to environmental factors over successive Western European cohorts, consistent perhaps with improvements in diagnosis and in prenatal and perinatal care and with a secular decline in the prevalence of schizophrenia in that region.

  6. The contribution of diet and genotype to iron status in women: a classical twin study.

    Science.gov (United States)

    Fairweather-Tait, Susan J; Guile, Geoffrey R; Valdes, Ana M; Wawer, Anna A; Hurst, Rachel; Skinner, Jane; Macgregor, Alexander J

    2013-01-01

    This is the first published report examining the combined effect of diet and genotype on body iron content using a classical twin study design. The aim of this study was to determine the relative contribution of genetic and environmental factors in determining iron status. The population was comprised of 200 BMI- and age-matched pairs of MZ and DZ healthy twins, characterised for habitual diet and 15 iron-related candidate genetic markers. Variance components analysis demonstrated that the heritability of serum ferritin (SF) and soluble transferrin receptor was 44% and 54% respectively. Measured single nucleotide polymorphisms explained 5% and selected dietary factors 6% of the variance in iron status; there was a negative association between calcium intake and body iron (p = 0.02) and SF (p = 0.04).

  7. Associations Between Fast-Food Consumption and Body Mass Index: A Cross-Sectional Study in Adult Twins.

    Science.gov (United States)

    Cohen-Cline, Hannah; Lau, Richard; Moudon, Anne V; Turkheimer, Eric; Duncan, Glen E

    2015-08-01

    Obesity is a substantial health problem in the United States, and is associated with many chronic diseases. Previous studies have linked poor dietary habits to obesity. This cross-sectional study aimed to identify the association between body mass index (BMI) and fast-food consumption among 669 same-sex adult twin pairs residing in the Puget Sound region around Seattle, Washington. We calculated twin-pair correlations for BMI and fast-food consumption. We next regressed BMI on fast-food consumption using generalized estimating equations (GEE), and finally estimated the within-pair difference in BMI associated with a difference in fast-food consumption, which controls for all potential genetic and environment characteristics shared between twins within a pair. Twin-pair correlations for fast-food consumption were similar for identical (monozygotic; MZ) and fraternal (dizygotic; DZ) twins, but were substantially higher in MZ than DZ twins for BMI. In the unadjusted GEE model, greater fast-food consumption was associated with larger BMI. For twin pairs overall, and for MZ twins, there was no association between within-pair differences in fast-food consumption and BMI in any model. In contrast, there was a significant association between within-pair differences in fast-food consumption and BMI among DZ twins, suggesting that genetic factors play a role in the observed association. Thus, although variance in fast-food consumption itself is largely driven by environmental factors, the overall association between this specific eating behavior and BMI is largely due to genetic factors.

  8. Zygosity differences in height and body mass index of twins from infancy to old age: A study of the CODATwins project

    Science.gov (United States)

    Jelenkovic, Aline; Yokoyama, Yoshie; Sund, Reijo; Honda, Chika; Bogl, Leonie H; Aaltonen, Sari; Ji, Fuling; Ning, Feng; Pang, Zengchang; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Burt, S Alexandra; Klump, Kelly L; Medland, Sarah E; Montgomery, Grant W; Kandler, Christian; McAdams, Tom A; Eley, Thalia C; Gregory, Alice M; Saudino, Kimberly J; Dubois, Lise; Boivin, Michel; Tarnoki, Adam D; Tarnoki, David L; Haworth, Claire MA; Plomin, Robert; Öncel, Sevgi Y; Aliev, Fazil; Stazi, Maria A; Fagnani, Corrado; D'Ippolito, Cristina; Craig, Jeffrey M; Saffery, Richard; Siribaddana, Sisira H; Hotopf, Matthew; Sumathipala, Athula; Rijsdijk, Fruhling; Spector, Timothy; Mangino, Massimo; Lachance, Genevieve; Gatz, Margaret; Butler, David A; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Freitas, Duarte L; Maia, José Antonio; Harden, K Paige; Tucker-Drob, Elliot M; Kim, Bia; Chong, Youngsook; Hong, Changhee; Shin, Hyun Jung; Christensen, Kaare; Skytthe, Axel; Kyvik, Kirsten O; Derom, Catherine A; Vlietinck, Robert F; Loos, Ruth JF; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; He, Mingguang; Ding, Xiaohu; Chang, Billy; Silberg, Judy L; Eaves, Lindon J; Maes, Hermine H; Cutler, Tessa L; Hopper, John L; Aujard, Kelly; Magnusson, Patrik KE; Pedersen, Nancy L; Aslan, Anna K Dahl; Song, Yun-Mi; Yang, Sarah; Lee, Kayoung; Baker, Laura A; Tuvblad, Catherine; Bjerregaard-Andersen, Morten; Beck-Nielsen, Henning; Sodemann, Morten; Heikkilä, Kauko; Tan, Qihua; Zhang, Dongfeng; Swan, Gary E; Krasnow, Ruth; Jang, Kerry L; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Lichtenstein, Paul; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Tynelius, Per; Duncan, Glen E; Buchwald, Dedra; Corley, Robin P; Huibregtse, Brooke M; Nelson, Tracy L; Whitfield, Keith E; Franz, Carol E; Kremen, William S; Lyons, Michael J; Ooki, Syuichi; Brandt, Ingunn; Nilsen, Thomas Sevenius; Inui, Fujio; Watanabe, Mikio; Bartels, Meike; van Beijsterveldt, Toos CEM; Wardle, Jane; Llewellyn, Clare H; Fisher, Abigail; Rebato, Esther; Martin, Nicholas G; Iwatani, Yoshinori; Hayakawa, Kazuo; Sung, Joohon; Harris, Jennifer R; Willemsen, Gonneke; Busjahn, Andreas; Goldberg, Jack H; Rasmussen, Finn; Hur, Yoon-Mi; Boomsma, Dorret I; Sørensen, Thorkild IA; Kaprio, Jaakko; Silventoinen, Karri

    2015-01-01

    A trend towards greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in means and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the CODATwins project and included 842,951 height and BMI measurements from age 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Likewise, a greater mean BMI of up to 0.3 kg/m2 in childhood and adolescence and up to 0.2 kg/m2 in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast the variance of BMI was significantly higher in DZ than in MZ twins particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes. PMID:26337138

  9. Aging Trajectories in Different Body Systems Share Common Environmental Etiology: The Healthy Aging Twin Study (HATS).

    Science.gov (United States)

    Moayyeri, Alireza; Hart, Deborah J; Snieder, Harold; Hammond, Christopher J; Spector, Timothy D; Steves, Claire J

    2016-02-01

    Little is known about the extent to which aging trajectories of different body systems share common sources of variance. We here present a large twin study investigating the trajectories of change in five systems: cardiovascular, respiratory, skeletal, morphometric, and metabolic. Longitudinal clinical data were collected on 3,508 female twins in the TwinsUK registry (complete pairs:740 monozygotic (MZ), 986 dizygotic (DZ), mean age at entry 48.9 ± 10.4, range 18-75 years; mean follow-up 10.2 ± 2.8 years, range 4-17.8 years). Panel data on multiple age-related variables were used to estimate biological ages for each individual at each time point, in linear mixed effects models. A weighted average approach was used to combine variables within predefined body system groups. Aging trajectories for each system in each individual were then constructed using linear modeling. Multivariate structural equation modeling of these aging trajectories showed low genetic effects (heritability), ranging from 2% in metabolic aging to 22% in cardiovascular aging. However, we found a significant effect of shared environmental factors on the variations in aging trajectories in cardiovascular (54%), skeletal (34%), morphometric (53%), and metabolic systems (53%). The remainder was due to environmental factors unique to each individual plus error. Multivariate Cholesky decomposition showed that among aging trajectories for various body systems there were significant and substantial correlations between the unique environmental latent factors as well as shared environmental factors. However, there was no evidence for a single common factor for aging. This study, the first of its kind in aging, suggests that diverse organ systems share non-genetic sources of variance for aging trajectories. Confirmatory studies are needed using population-based twin cohorts and alternative methods of handling missing data.

  10. Epigenome-Wide Association Study of Cognitive Functioning in Middle-Aged Monozygotic Twins

    DEFF Research Database (Denmark)

    Starnawska, Anna; Tan, Qihua; McGue, Matt

    2017-01-01

    As the world's population ages, the age-related cognitive decline presents a great challenge to world's healthcare systems. One of the molecular mechanisms implicated in cognitive ageing is DNA methylation, an epigenetic modification known to be a key player in memory formation, maintenance......, and synaptic plasticity. Using the twin design we performed an epigenome-wide association study (EWAS) in a population of 486 middle-aged monozygotic twins (mean age at follow-up 65.9, SD = 6.1) and correlated their blood DNA methylation to their level (cross-sectional analysis) and change in cognitive...... abilities over 10 years (longitudinal analysis). We identified several CpG sites where cross-sectional cognitive functioning was associated with DNA methylation levels. The top identified loci were located in ZBTB46 (p = 5.84 × 10-7), and TAF12 (p = 4.91 × 10-7). KEGG's enrichment analyses of the most...

  11. Importance of genetic factors in the occurrence of epilepsy syndrome type: a twin study

    DEFF Research Database (Denmark)

    Corey, Linda A; Pellock, John M; Kjeldsen, Marianne J

    2011-01-01

    not appear to play an important role in determining risk for frontal, occipital or temporal lobe epilepsy. These results suggest that, while genetic factors contribute to risk for major syndrome types, determined when possible, their contribution to risk for localization-related syndrome sub......Although there is strong evidence that genetic factors contribute to risk for epilepsy, their role in the determination of syndrome type is less clear. This study was undertaken to address this question. Information related to epilepsy was obtained from twins included in 455 monozygotic and 868...... dizygotic pairs ascertained from population-based twin registries in Denmark, Norway and the United States. Syndrome type was determined based on medical record information and detailed clinical interviews and classified using the International Classification Systems for the Epilepsies and Epileptic...

  12. Migraine and risk of stroke: a national population-based twin study.

    Science.gov (United States)

    Lantz, Maria; Sieurin, Johanna; Sjölander, Arvid; Waldenlind, Elisabet; Sjöstrand, Christina; Wirdefeldt, Karin

    2017-10-01

    Numerous studies have indicated an increased risk for stroke in patients with migraine, especially migraine with aura; however, many studies used self-reported migraine and only a few controlled for familial factors. We aimed to investigate migraine as a risk factor for stroke in a Swedish population-based twin cohort, and whether familial factors contribute to an increased risk. The study population included twins without prior cerebrovascular disease who answered a headache questionnaire during 1998 and 2002 for twins born 1935-58 and during 2005-06 for twins born between 1959 and 1985. Migraine with and without aura and probable migraine was defined by an algorithm mapping on to clinical diagnostic criteria according to the International Classification of Headache Disorders. Stroke diagnoses were obtained from the national patient and cause of death registers. Twins were followed longitudinally, by linkage of national registers, from date of interview until date of first stroke, death, or end of study on 31 Dec 2014. In total, 8635 twins had any migraineous headache, whereof 3553 had migraine with aura and 5082 had non-aura migraineous headache (including migraine without aura and probable migraine), and 44 769 twins had no migraine. During a mean follow-up time of 11.9 years we observed 1297 incident cases of stroke. The Cox proportional hazards model with attained age as underlying time scale was used to estimate hazard ratios with 95% confidence intervals for stroke including ischaemic and haemorrhagic subtypes related to migraine with aura, non-aura migraineous headache, and any migraineous headache. Analyses were adjusted for gender and cardiovascular risk factors. Where appropriate; within-pair analyses were performed to control for confounding by familial factors. The age- and gender-adjusted hazard ratio for stroke related to migraine with aura was 1.27 (95% confidence interval 1.00-1.62), P = 0.05, and 1.07 (95% confidence interval 0.91-1.26), P = 0

  13. Twin study of heritability of eating bread in Danish and Finnish men and women

    DEFF Research Database (Denmark)

    Hasselbalch, Ann Louise; Silventoinen, Karri; Keskitalo, Kaisu

    2010-01-01

    magnitude of the additive genetic, shared environmental and individual environmental effects on bread eating frequency and choice of bread. The analysis of bread intake frequency demonstrated moderate heritability ranging from 37-40% in the Finnish cohort and 23-26% in the Danish cohort. The genetic...... predisposition. Environmental factors shared by the co-twins (e.g., childhood environment) seem to have no significant effects on bread consumption and preference in adulthood.......Bread is an elementary part of the western diet, and especially rye bread is regarded as an important source of fibre. We investigated the heritability of eating bread in terms of choice of white and rye bread and use-frequency of bread in female and male twins in Denmark and Finland. The study...

  14. Genetic Complexity of Episodic Memory: A Twin Approach to Studies of Aging

    Science.gov (United States)

    Kremen, William S.; Spoon, Kelly M.; Jacobson, Kristen C.; Vasilopoulos, Terrie; McCaffery, Jeanne M.; Panizzon, Matthew S.; Franz, Carol E.; Vuoksimaa, Eero; Xian, Hong; Rana, Brinda K.; Toomey, Rosemary; McKenzie, Ruth; Lyons, Michael J.

    2016-01-01

    Episodic memory change is a central issue in cognitive aging, and understanding that process will require elucidation of its genetic underpinnings. A key limiting factor in genetically informed research on memory has been lack of attention to genetic and phenotypic complexity, as if “memory is memory” and all well-validated assessments are essentially equivalent. Here we applied multivariate twin models to data from late-middle-aged participants in the Vietnam Era Twin Study of Aging to examine the genetic architecture of 6 measures from 3 standard neuropsychological tests: the California Verbal Learning Test-2, and Wechsler Memory Scale-III Logical Memory (LM) and Visual Reproductions (VR). An advantage of the twin method is that it can estimate the extent to which latent genetic influences are shared or independent across different measures before knowing which specific genes are involved. The best-fitting model was a higher order common pathways model with a heritable higher order general episodic memory factor and three test-specific subfactors. More importantly, substantial genetic variance was accounted for by genetic influences that were specific to the latent LM and VR subfactors (28% and 30%, respectively) and independent of the general factor. Such unique genetic influences could partially account for replication failures. Moreover, if different genes influence different memory phenotypes, they could well have different age-related trajectories. This approach represents an important step toward providing critical information for all types of genetically informative studies of aging and memory. PMID:24956007

  15. The Role of Nature and Nurture for Individual Differences in Primary Emotional Systems: Evidence from a Twin Study.

    Directory of Open Access Journals (Sweden)

    Christian Montag

    Full Text Available The present study investigated for the first time the relative importance of genetics and environment on individual differences in primary emotionality as measured with the Affective Neuroscience Personality Scales (ANPS by means of a twin-sibling study design. In N = 795 participants (n = 303 monozygotic twins, n = 172 dizygotic twins and n = 267 non-twin full siblings, moderate to strong influences of genetics on individual differences in these emotional systems are observed. Lowest heritability estimates are presented for the SEEKING system (33% and highest for the PLAY system (69%. Further, multivariate genetic modeling was applied to the data showing that associations among the six ANPS scales were influences by both, a genetic as well as an environmental overlap between them. In sum, the study underlines the usefulness of the ANPS for biologically oriented personality psychology research.

  16. Discordant tooth agenesis and peg-shaped in a pair of monozygotic twins: Clinical and molecular study

    Directory of Open Access Journals (Sweden)

    Lívia Azeredo Alves Antunes

    2013-01-01

    Full Text Available The present report aimed to study an uncommon case of a pair of twins that presented a discordant dental phenotype. Family investigation, clinical, radiographic examination and molecular analysis were performed in both girls. Molecular analysis confirmed the monozygosity by deoxyribonucleic acid chip technology. One twin presented tooth agenesis in left upper lateral incisor and peg-shaped on the contra lateral side while the other twin had no dental alterations. The dental casts study employed digital caliper to compare morphological dimensions and showed alteration only in peg-shaped tooth. In conclusion, this study provide support that one or more mutated gene could cause discordances in dental phenotype in these monozygotic twins.

  17. The Danish Twin Registry

    DEFF Research Database (Denmark)

    Skytthe, Axel; Ohm Kyvik, Kirsten; Vilstrup Holm, Niels

    2011-01-01

    Introduction: The Danish Twin Registry is a unique source for studies of genetic, familial and environmental factors on life events, health conditions and diseases. Content: More than 85,000 twin pairs born 1870-2008 in Denmark. Validity and coverage: Four main ascertainment methods have been emp...

  18. Chronic prostatitis and comorbid non-urological overlapping pain conditions: A co-twin control study.

    Science.gov (United States)

    Gasperi, Marianna; Krieger, John N; Forsberg, Christopher; Goldberg, Jack; Buchwald, Dedra; Afari, Niloofar

    2017-11-01

    Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is characterized by pain and voiding symptoms in the absence of an obvious infection or other cause. CP/CPPS frequently occurs with non-urological chronic overlapping pain conditions (COPCs) of unknown etiology. We conducted a co-twin control study in men discordant for chronic prostatitis (CP), an overarching diagnosis of which approximately 90% is CP/CPPS. The primary aim was to investigate the contribution of familial factors, including shared genetic and common environmental factors, to the comorbidity of CP and COPCs. Data from 6824 male twins in the Vietnam Era Twin Registry were examined to evaluate the association between self-reported lifetime physician diagnosis of CP with COPCs including fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, temporomandibular disorder, tension headaches, and migraine headaches. Random effects logistic regression models were used and within-pair analyses evaluated confounding effects of familial factors on the associations. There were significant associations between CP and all 6 examined COPCs. After adjusting for shared familial influences in within twin pair analyses, the associations for all COPCs diminished but remained significant. Familial confounding was strongest for the association of CP with fibromyalgia and temporomandibular disorder and smallest for irritable bowel syndrome. CP and COPCs are highly comorbid. These associations can be partially explained by familial factors. The mechanisms underlying these relationships are likely diverse and multifactorial. Future longitudinal research can help to further elucidate specific genetic and environmental mechanisms and determine potentially causal relationships between CP and its comorbidities. Published by Elsevier Inc.

  19. Responsiveness to exercise training in juvenile dermatomyositis: a twin case study

    Directory of Open Access Journals (Sweden)

    Roschel Hamilton

    2010-11-01

    Full Text Available Abstract Background Patients with juvenile dermatomyositis (JDM often present strong exercise intolerance and muscle weakness. However, the role of exercise training in this disease has not been investigated. Purpose this longitudinal case study reports on the effects of exercise training on a 7-year-old patient with JDM and on her unaffected monozygotic twin sister, who served as a control. Methods Both the patient who was diagnosed with JDM as well as her healthy twin underwent a 16-week exercise training program comprising aerobic and strengthening exercises. We assessed one repetition-maximum (1-RM leg-press and bench-press strength, balance, mobility and muscle function, blood markers of inflammation and muscle enzymes, aerobic conditioning, and disease activity scores. As a result, the healthy child had an overall greater absolute strength, muscle function and aerobic conditioning compared to her JDM twin pair at baseline and after the trial. However, the twins presented comparable relative improvements in 1-RM bench press, 1-RM leg press, VO2peak, and time-to-exhaustion. The healthy child had greater relative increments in low-back strength and handgrip, whereas the child with JDM presented a higher relative increase in ventilatory anaerobic threshold parameters and functional tests. Quality of life, inflammation, muscle damage and disease activity scores remained unchanged. Results and Conclusion this was the first report to describe the training response of a patient with non-active JDM following an exercise training regimen. The child with JDM exhibited improved strength, muscle function and aerobic conditioning without presenting an exacerbation of the disease.

  20. Genetic influences on variation in female orgasmic function: a twin study

    Science.gov (United States)

    Dunn, Kate M; Cherkas, Lynn F; Spector, Tim D

    2005-01-01

    Orgasmic dysfunction in females is commonly reported in the general population with little consensus on its aetiology. We performed a classical twin study to explore whether there were observable genetic influences on female orgasmic dysfunction. Adult females from the TwinsUK register were sent a confidential survey including questions on sexual problems. Complete responses to the questions on orgasmic dysfunction were obtained from 4037 women consisting of 683 monozygotic and 714 dizygotic pairs of female twins aged between 19 and 83 years. One in three women (32%) reported never or infrequently achieving orgasm during intercourse, with a corresponding figure of 21% during masturbation. A significant genetic influence was seen with an estimated heritability for difficulty reaching orgasm during intercourse of 34% (95% confidence interval 27–40%) and 45% (95% confidence interval 38–52%) for orgasm during masturbation. These results show that the wide variation in orgasmic dysfunction in females has a genetic basis and cannot be attributed solely to cultural influences. These results should stimulate further research into the biological and perhaps evolutionary processes governing female sexual function. PMID:17148182

  1. Causes and consequences of obesity: the contribution of recent twin studies.

    Science.gov (United States)

    Naukkarinen, J; Rissanen, A; Kaprio, J; Pietiläinen, K H

    2012-08-01

    Obesity is a genetically complex disorder that produces a myriad of health problems. Most of the recognized complications of obesity are not only strongly influenced by lifestyle factors, but also present with independent genetic predispositions that are notoriously difficult to disentangle in humans. Most studies on the causes and consequences of acquired obesity are encumbered by the incomplete ability to control for genetic influences. However, utilizing a unique experiment of nature, namely monozygotic twins (MZ) discordant for obesity as 'clonal controls' of obese and non-obese individuals has enabled the fine characterization of the effects and possible antecedents of acquired obesity while controlling for the genetic background, as well as pointed to novel obesity predisposing candidate genes. This review is a distillation of the findings from more than 10 years of research done in an exceptionally well-characterized collection of MZ and dizygotic (DZ) twins, based on the Finnish Twin Cohorts. Topics covered include the nature of development of obesity from the childhood onwards, the role of exercise in modifying the genetic susceptibility, the resulting inflammatory, prediabetic and preatherosclerotic changes in whole body and adipose tissue physiology, as well as the newest insights provided by the omics revolution.

  2. Causes of individual differences in adolescent optimism: a study in Dutch twins and their siblings.

    Science.gov (United States)

    Mavioğlu, Rezan Nehir; Boomsma, Dorret I; Bartels, Meike

    2015-11-01

    The aim of this study was to investigate the degree to which genetic and environmental influences affect variation in adolescent optimism. Optimism (3 items and 6 items approach) and pessimism were assessed by the Life Orientation Test-Revised (LOT-R) in 5,187 adolescent twins and 999 of their non-twin siblings from the Netherlands Twin Register (NTR). Males reported significantly higher optimism scores than females, while females score higher on pessimism. Genetic structural equation modeling revealed that about one-third of the variance in optimism and pessimism was due to additive genetic effects, with the remaining variance being explained by non-shared environmental effects. A bivariate correlated factor model revealed two dimensions with a genetic correlation of -.57 (CI -.67, -.47), while the non-shared environmental correlation was estimated to be -.21 (CI -.25, -.16). Neither an effect of shared environment, non-additive genetic influences, nor quantitative sex differences was found for both dimensions. This result indicates that individual differences in adolescent optimism are mainly accounted for by non-shared environmental factors. These environmental factors do not contribute to the similarity of family members, but to differences between them. Familial resemblance in optimism and pessimism assessed in adolescents is fully accounted for by genetic overlap between family members.

  3. Childhood social class and cognitive aging in the Swedish Adoption/Twin Study of Aging.

    Science.gov (United States)

    Ericsson, Malin; Lundholm, Cecilia; Fors, Stefan; Dahl Aslan, Anna K; Zavala, Catalina; Reynolds, Chandra A; Pedersen, Nancy L

    2017-07-03

    In this report we analyzed genetically informative data to investigate within-person change and between-person differences in late-life cognitive abilities as a function of childhood social class. We used data from nine testing occasions spanning 28 y in the Swedish Adoption/Twin Study of Aging and parental social class based on the Swedish socioeconomic index. Cognitive ability included a general factor and the four domains of verbal, fluid, memory, and perceptual speed. Latent growth curve models of the longitudinal data tested whether level and change in cognitive performance differed as a function of childhood social class. Between-within twin-pair analyses were performed on twins reared apart to assess familial confounding. Childhood social class was significantly associated with mean-level cognitive performance at age 65 y, but not with rate of cognitive change. The association decreased in magnitude but remained significant after adjustments for level of education and the degree to which the rearing family was supportive toward education. A between-pair effect of childhood social class was significant in all cognitive domains, whereas within-pair estimates were attenuated, indicating genetic confounding. Thus, childhood social class is important for cognitive performance in adulthood on a population level, but the association is largely attributable to genetic influences.

  4. Heritability of the morphology of optic nerve head and surrounding structures: The Healthy Twin Study.

    Directory of Open Access Journals (Sweden)

    Jong Chul Han

    Full Text Available Optic nerve head (ONH and surrounding structures such as β-zone peripapillary atrophy (PPA are important structures in glaucomatous pathogenesis. Thus, for understanding genetic components in glaucoma pathogenesis, it is necessary to evaluate the heritability of ONH and surrounding structures. The present study investigated the genetic influences on ONH and surrounding structures such as β-zone PPA and retinal vessels.A total of 1,205 adult twins and their family members (362 monozygotic (MZ twin subjects (181 pairs, 64 dizygotic (DZ twin subjects (32 pairs, and 779 singletons from 261 families, were part of the Korean Healthy Twin Study. ONH parameters including the vertical cup-to-disc ratio, the presence, the area and the location of β-zone PPA and the angular location of retinal vein were measured. The genetic influences on the structures were evaluated using variance-component methods.The intraclass correlation coefficient (ICC values of axial length were highest among the parameters. The ICCs of the area and location of PPA were similar to those of vertical cup-to-disc ratio. However, retinal vessel angular locations showed low ICC values even in MZ twins. After age and sex adjustment, for axial length, vertical cup-to-disc ratio, the presence, area and location of PPA, the estimated narrow-sense heritability was 0.85, 0.48, 0.76, 0.50 and 0.65 in the right eye and 0.84, 0.47, 0.72, 0.46 and 0.72 in the left eye, respectively. The estimated narrow-sense heritability of angular location of the superior and inferior vein was 0.17 and 0.12 in the right eye and 0.13 and 0.05 in the left eye, respectively.ONH and surrounding structures such as vertical cup-to-disc ratio and the presence, the area and the location of β-zone PPA seemed to be determined by the substantial genetic influence, whereas the venous angular location did not.

  5. The effects of parental education on exercise behavior in childhood and youth: a study in Dutch and Finnish twins.

    Science.gov (United States)

    Huppertz, C; Bartels, M; de Geus, E J C; van Beijsterveldt, C E M; Rose, R J; Kaprio, J; Silventoinen, K

    2017-10-01

    Twin studies have estimated the relative contribution of genes and the environment to variance in exercise behavior and it is known that parental education positively affects exercise levels. This study investigates the role of parental education as a potential modifier of variance in exercise behavior from age 7 to 18 years. The study is based on large datasets from the Netherlands Twin Register (NTR: N = 24 874 twins; surveys around the ages of 7, 10, 12, 14, 16 and 18 years) and two Finnish twin cohorts (FinnTwin12: N = 4399; 12, 14 and 17 years; FinnTwin16: N = 4648; 16, 17 and 18 years). Regular participation in moderate-to-vigorous exercise activities during leisure time was assessed by survey. Parental education was dichotomized ("both parents with a low education" vs "at least one parent with a high education"). The mean in exercise behavior tended to be higher and the variance tended to be lower in children of high educated parents. Evidence for gene-by-environment interaction was weak. To develop successful interventions that specifically target children of low educated parents, the mechanisms causing the mean and variance differences between the two groups should be better understood. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Twin cities institutional issues study cogenerated hot water district heating

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, R. E.; Leas, R.; Kolb, J. O.

    1979-01-01

    Community district heating, utilizing hot water produced through electrical/thermal cogeneration, is seen as an integral part of Minnesota's Energy Policy and Conservation Plan. Several studies have been conducted which consider the technical and institutional issues affecting implementation of cogenerated district heating in the Minneapolis and St. Paul Metropolitan Area. The state of the technical art of cogenerated hot water district heating is assumed to be transferable from European experience. Institutional questions relating to such factors as the form of ownership, financing, operation, regulation, and product marketability cannot be transferred from the European experience, and have been the subject of an extensive investigation. The form and function of the Institutional Issues Study, and some of the preliminary conclusions and recommendations resulting from the study are discussed.

  7. Subjective wellbeing and longevity: a co-twin control study

    DEFF Research Database (Denmark)

    Sadler, Michael E; Miller, Christopher J; Christensen, Kaare

    2011-01-01

    Mental health is increasingly defined not only by the absence of illness but by the presence of subjective well-being (SWB). Previous cohort studies have consistently shown that indicators of SWB predict favorable life outcomes, including better mental and somatic health, and longevity....... The favorable effects associated with SWB have prompted new research aimed at raising happiness and wellbeing through individual interventions and public health initiatives. Standard observational studies of individual-level associations, however, are subject to potential confounding of exposure and outcome...

  8. Heritability of tic disorders : a twin-family study

    NARCIS (Netherlands)

    Rodrigues Zilhao Nogueira, N.; Olthof, M C; Smit, D J A; Cath, D.C.; Ligthart, L; Mathews, C.A.; Delucchi, K.; Boomsma, D I; Dolan, C V

    BACKGROUND: Genetic-epidemiological studies that estimate the contributions of genetic factors to variation in tic symptoms are scarce. We estimated the extent to which genetic and environmental influences contribute to tics, employing various phenotypic definitions ranging between mild and severe

  9. Heritability of tic disorders : a twin-family study

    NARCIS (Netherlands)

    Rodrigues Zilhao Nogueira, Nuno; Olthof, M C; Smit, D J A; Cath, D C; Ligthart, L; Mathews, C A; Delucchi, K; Boomsma, D I; Dolan, C V

    2017-01-01

    BACKGROUND: Genetic-epidemiological studies that estimate the contributions of genetic factors to variation in tic symptoms are scarce. We estimated the extent to which genetic and environmental influences contribute to tics, employing various phenotypic definitions ranging between mild and severe

  10. Familial clustering in burnout: a twin-family study

    NARCIS (Netherlands)

    Middeldorp, C.M.; Stubbe, J.H.; Cath, D.C.; Boomsma, D.I.

    2005-01-01

    Background. Research on risk factors for burnout has mainly focused on circumstances at work and on personal characteristics. The aim of this study was to investigate whether burnout clusters within families and, if so, whether this is due to genetic influences or to environmental factors shared by

  11. Predictors of fibromyalgia: a population-based twin cohort study

    OpenAIRE

    Markkula, Ritva A; Kalso, Eija A; Kaprio, Jaakko A

    2016-01-01

    Abstract Background Fibromyalgia (FM) is a pain syndrome, the mechanisms and predictors of which are still unclear. We have earlier validated a set of FM-symptom questions for detecting possible FM in an epidemiological survey and thereby identified a cluster with “possible FM”. This study explores prospectively predictors for membership of that FM-symptom cluster. Methods ...

  12. Epidemiology of Anorexia Nervosa in Men : A Nationwide Study of Finnish Twins

    NARCIS (Netherlands)

    Raevuori, Anu; Hoek, Hans W.; Susser, Ezra; Kaprio, Jaakko; Rissanen, Aila; Keski-Rahkonen, Anna

    2009-01-01

    Background: To examine the epidemiology of anorexia nervosa in men, we screened Finnish male twins born in 1975-79. Methods and Findings: Men (N = 2122) from FinnTwin16 birth cohorts were screened for lifetime eating disorders by a questionnaire. The screen positives (N = 18), their male co-twins (N

  13. A Computational Discriminability Analysis on Twin Fingerprints

    Science.gov (United States)

    Liu, Yu; Srihari, Sargur N.

    Sharing similar genetic traits makes the investigation of twins an important study in forensics and biometrics. Fingerprints are one of the most commonly found types of forensic evidence. The similarity between twins’ prints is critical establish to the reliability of fingerprint identification. We present a quantitative analysis of the discriminability of twin fingerprints on a new data set (227 pairs of identical twins and fraternal twins) recently collected from a twin population using both level 1 and level 2 features. Although the patterns of minutiae among twins are more similar than in the general population, the similarity of fingerprints of twins is significantly different from that between genuine prints of the same finger. Twins fingerprints are discriminable with a 1.5%~1.7% higher EER than non-twins. And identical twins can be distinguished by examine fingerprint with a slightly higher error rate than fraternal twins.

  14. The effects of labor and delivery on maternal and neonatal outcomes in term twins: a retrospective cohort study.

    Science.gov (United States)

    Wenckus, D J; Gao, W; Kominiarek, M A; Wilkins, I

    2014-08-01

    To compare maternal and neonatal outcomes in twins undergoing a trial of labor versus pre-labor caesarean. Retrospective cohort study. 19 US hospitals from the Consortium on Safe Labor. Of 2225 twin sets ≥36 weeks' gestation. Maternal (abruption, estimated blood loss, postpartum haemorrhage, transfusion, chorioamnionitis, hysterectomy, ICU admission, death) and neonatal outcomes (birth injury, 5-minute Apgar <7, NICU admission, RDS, TTN, sepsis, asphyxia, NICU length of stay, death) were compared between the trial of labour and pre-labour caesarean groups with univariate and multivariate logistic and linear regression analyses. Similar analyses were performed for actual delivery modes. Maternal and neonatal outcomes. Among the 2225 twin sets, 1078 had a trial of labour, and 65.9% of those delivered vaginally. There was an increased risk for postpartum haemorrhage [OR 2.5, 95% confidence interval (CI) 1.4-4.5] and blood transfusion (OR 1.9, 95%CI 1.2-3.2) for the trial of labour compared with pre-labour caesarean groups. Birth injury only occurred in the trial of labour group, 1% Twin A, 0.4% Twin B. Both twins had a higher risk of 5-minute Apgar <7 with trial of labour compared to pre-labour caesarean (A: OR 3.9, 95%CI 1.05-14.5; B: OR 3.9, 95%CI 1.3-12.3). Term twins undergoing a trial of labour have increased maternal haemorrhage and transfusions along with neonatal birth trauma and lower Apgar scores, but these absolute neonatal occurrences were rare. Trial of labour in twins remains a safe and reasonable option in appropriately selected cases. © 2014 Royal College of Obstetricians and Gynaecologists.

  15. A study of asthma severity in adult twins

    DEFF Research Database (Denmark)

    Thomsen, Simon Francis; van der Sluis, Sophie; Kyvik, Kirsten Ohm

    2012-01-01

    Introduction: The tendency to develop asthma runs in families, but whether the severity of asthma symptoms is inherited is not known. Objectives: The aim of this study was to examine whether genetic factors influence the variation in the severity of asthma. Methods: Of a sample of 21 133 adult......, and markers of airway impairment and allergy were measured. Results: After adjusting for confounders, genetic factors explained 24% (10%-37%), P = 0.0004, of the variation in overall asthma symptom severity, whereas non-shared environment accounted for the remaining 76% of the variation. A significant genetic...

  16. Genetics of dietary habits and obesity - a twin study

    DEFF Research Database (Denmark)

    Hasselbalch, Ann Louise

    2010-01-01

    influences on dietary intake in adults and the interplay between diet, genes and obesity. The focus of the thesis was to investigate the genetic and environmental influence on habitual diet and obesity as well as the association between habitual diet and anthropometry. The thesis is based on structural....... The study showed, however, consistent positive associations between intake of sugar-sweetened soft drink and BMI, FMI and waist circumference in men. Gene-environment interaction models showed that while high physical activity is associated with a down-regulation of genes predisposing to obesity......Obesity has become a major health concern due to the increased risk of co-morbidities, resulting in decreased quality of life, stigmatization, reduced working ability and early death. This causes a great challenge for the health care systems and results in increased direct costs related...

  17. Zygosity Differences in Height and Body Mass Index of Twins From Infancy to Old Age: A Study of the CODATwins Project.

    Science.gov (United States)

    Jelenkovic, Aline; Yokoyama, Yoshie; Sund, Reijo; Honda, Chika; Bogl, Leonie H; Aaltonen, Sari; Ji, Fuling; Ning, Feng; Pang, Zengchang; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Burt, S Alexandra; Klump, Kelly L; Medland, Sarah E; Montgomery, Grant W; Kandler, Christian; McAdams, Tom A; Eley, Thalia C; Gregory, Alice M; Saudino, Kimberly J; Dubois, Lise; Boivin, Michel; Tarnoki, Adam D; Tarnoki, David L; Haworth, Claire M A; Plomin, Robert; Öncel, Sevgi Y; Aliev, Fazil; Stazi, Maria A; Fagnani, Corrado; D'Ippolito, Cristina; Craig, Jeffrey M; Saffery, Richard; Siribaddana, Sisira H; Hotopf, Matthew; Sumathipala, Athula; Rijsdijk, Fruhling; Spector, Timothy; Mangino, Massimo; Lachance, Genevieve; Gatz, Margaret; Butler, David A; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Freitas, Duarte L; Maia, José Antonio; Harden, K Paige; Tucker-Drob, Elliot M; Kim, Bia; Chong, Youngsook; Hong, Changhee; Shin, Hyun Jung; Christensen, Kaare; Skytthe, Axel; Kyvik, Kirsten O; Derom, Catherine A; Vlietinck, Robert F; Loos, Ruth J F; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; He, Mingguang; Ding, Xiaohu; Chang, Billy; Silberg, Judy L; Eaves, Lindon J; Maes, Hermine H; Cutler, Tessa L; Hopper, John L; Aujard, Kelly; Magnusson, Patrik K E; Pedersen, Nancy L; Aslan, Anna K Dahl; Song, Yun-Mi; Yang, Sarah; Lee, Kayoung; Baker, Laura A; Tuvblad, Catherine; Bjerregaard-Andersen, Morten; Beck-Nielsen, Henning; Sodemann, Morten; Heikkilä, Kauko; Tan, Qihua; Zhang, Dongfeng; Swan, Gary E; Krasnow, Ruth; Jang, Kerry L; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Lichtenstein, Paul; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Tynelius, Per; Duncan, Glen E; Buchwald, Dedra; Corley, Robin P; Huibregtse, Brooke M; Nelson, Tracy L; Whitfield, Keith E; Franz, Carol E; Kremen, William S; Lyons, Michael J; Ooki, Syuichi; Brandt, Ingunn; Nilsen, Thomas Sevenius; Inui, Fujio; Watanabe, Mikio; Bartels, Meike; van Beijsterveldt, Toos C E M; Wardle, Jane; Llewellyn, Clare H; Fisher, Abigail; Rebato, Esther; Martin, Nicholas G; Iwatani, Yoshinori; Hayakawa, Kazuo; Sung, Joohon; Harris, Jennifer R; Willemsen, Gonneke; Busjahn, Andreas; Goldberg, Jack H; Rasmussen, Finn; Hur, Yoon-Mi; Boomsma, Dorret I; Sørensen, Thorkild I A; Kaprio, Jaakko; Silventoinen, Karri

    2015-10-01

    A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), and included 842,951 height and BMI measurements from twins aged 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Similarly, a greater mean BMI of up to 0.3 kg/m2 in childhood and adolescence and up to 0.2 kg/m2 in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast, the variance of BMI was significantly higher in DZ than in MZ twins, particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes.

  18. Geographic Variation in Maternal Smoking during Pregnancy in the Missouri Adolescent Female Twin Study (MOAFTS)

    Science.gov (United States)

    Lian, Min; Madden, Pamela A.; Lynskey, Michael T.; Colditz, Graham A.; Lessov-Schlaggar, Christina N.; Schootman, Mario; Heath, Andrew C.

    2016-01-01

    Objective Despite well-known adverse health effects of maternal smoking during pregnancy (MSP), it is still unclear if MSP varies geographically and if neighborhood socioeconomic deprivation (SED) plays an important role in MSP. This study aims to investigate small-area geographic variation in MSP and examine the association of SED with MSP. Methods The Missouri Adolescent Female Twin Study (MOAFTS) is a cohort study of female like-sex twins born in Missouri to Missouri-resident parents during 1975–1985. Biological mothers completed a baseline interview in 1995–1998 and reported MSP with the twins. Residential address of the mother at birth was geocoded. We developed a census tract-level SED index using a common factor approach based on 21 area-level socioeconomic variables from the 1980 Census data. Multilevel logistic regressions estimated geographic heterogeneity (random effect) in MSP and the odds ratios (ORs, fixed effects) of neighborhood SED associated with MSP. Results Of 1658 MOAFTS mothers, 35.2% reported any MSP and 21.9% reported MSP beyond the first trimester. Neighborhood SED was associated with any MSP (the highest vs. the lowest quartile: OR = 1.90, 95% confidence interval [CI] = 1.40–2.57, Ptrendalcohol use, and parents’ cohabitation), neighborhood SED was not associated with MSP, but geographic variation still persisted in MSP (variance = 0.41, P = 0.003) and in MSP beyond the first trimester (variance = 0.82, P<0.001). Conclusions Neighborhood SED was associated with MSP in unadjusted analyses but this association could be explained by individual socioeconomic conditions. Nonetheless, significant geographic variation in MSP persisted and was not accounted for by differences in neighborhood SED. To develop effective interventions to reduce MSP, further studies are necessary to explore underlying reasons for its geographic variation. PMID:27100091

  19. Twin pregnancy

    DEFF Research Database (Denmark)

    Sperling, Lene; Tabor, A

    2001-01-01

    Determination of chorionicity is one of the most important issues in the management of twin pregnancy. Modern ultrasound equipment has made it possible to accurately assess placentation already in the first trimester with the lambda sign. With regard to prenatal diagnosis, it is important to know...... for clinicians caring for twin pregnancies....

  20. Atomic-scale studies on the effect of boundary coherency on stability in twinned Cu

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Rongmei; Han, Ke, E-mail: han@magnet.fsu.edu; Su, Yi-Feng; Salters, Vincent J. [National High Magnetic Field Laboratory, 1800 E. Paul Dirac Drive, Tallahassee, Florida 32310 (United States)

    2014-01-06

    The stored energy and hardness of nanotwinned (NT) Cu are related to interaction between dislocations and (111)-twin boundaries (TBs) studied at atomic scales by high-angle annular dark-field scanning transmission electron microscope. Lack of mobile dislocations at coherent TBs (CTBs) provides as-deposited NT Cu a rare combination of stability and hardness. The introduction of numerous incoherent TBs (ITBs) reduces both the stability and hardness. While storing more energy in their ITBs than in the CTBs, deformed NT Cu also exhibits high dislocation density and TB mobility and therefore has increased the driving force for recovery, coarsening, and recrystallization.

  1. Atomic-scale studies on the effect of boundary coherency on stability in twinned Cu

    Science.gov (United States)

    Niu, Rongmei; Han, Ke; Su, Yi-Feng; Salters, Vincent J.

    2014-01-01

    The stored energy and hardness of nanotwinned (NT) Cu are related to interaction between dislocations and {111}-twin boundaries (TBs) studied at atomic scales by high-angle annular dark-field scanning transmission electron microscope. Lack of mobile dislocations at coherent TBs (CTBs) provides as-deposited NT Cu a rare combination of stability and hardness. The introduction of numerous incoherent TBs (ITBs) reduces both the stability and hardness. While storing more energy in their ITBs than in the CTBs, deformed NT Cu also exhibits high dislocation density and TB mobility and therefore has increased the driving force for recovery, coarsening, and recrystallization.

  2. The Heritability of Insomnia Progression during Childhood/Adolescence: Results from a Longitudinal Twin Study

    Science.gov (United States)

    Barclay, Nicola L.; Gehrman, Philip R.; Gregory, Alice M.; Eaves, Lindon J.; Silberg, Judy L.

    2015-01-01

    Study Objectives: To determine prevalence and heritability of insomnia during middle/late childhood and adolescence; examine longitudinal associations in insomnia over time; and assess the extent to which genetic and environmental factors on insomnia remain stable, or whether new factors come into play, across this developmental period. Design: Longitudinal twin study. Setting: Academic medical center. Patients or Participants: There were 739 complete monozygotic twin pairs (52%) and 672 complete dizygotic twin pairs (48%) initially enrolled and were followed up at three additional time points (waves). Mode ages at each wave were 8, 10, 14, and 15 y (ages ranged from 8–18 y). Interventions: None. Measurements and Results: Clinical ratings of insomnia symptoms were assessed using the Child and Adolescent Psychiatric Assessment (CAPA) by trained clinicians, and rated according to Diagnostic and Statistical Manual of Mental Disorders, 3rd Edition—Revised criteria for presence of “clinically significant insomnia,” over four sequential waves. Insomnia symptoms were prevalent but significantly decreased across the four waves (ranging from 16.6% to 31.2%). “Clinically significant insomnia” was moderately heritable at all waves (h2 range = 14% to 38%), and the remaining source of variance was the nonshared environment. Multivariate models indicated that genetic influences at wave 1 contributed to insomnia at all subsequent waves, and that new genetic influences came into play at wave 2, which further contributed to stability of symptoms. Nonshared environmental influences were time-specific. Conclusion: Insomnia is prevalent in childhood and adolescence, and is moderately heritable. The progression of insomnia across this developmental time period is influenced by stable as well as new genetic factors that come into play at wave 2 (modal age 10 y). Molecular genetic studies should now identify genes related to insomnia progression during childhood and

  3. A multivariate twin study of the DSM-IV criteria for antisocial personality disorder.

    Science.gov (United States)

    Kendler, Kenneth S; Aggen, Steven H; Patrick, Christopher J

    2012-02-01

    Many assessment instruments for psychopathy are multidimensional, suggesting that distinguishable factors are needed to effectively capture variation in this personality domain. However, no prior study has examined the factor structure of the DSM-IV criteria for antisocial personality disorder (ASPD). Self-report questionnaire items reflecting all A criteria for DSM-IV ASPD were available from 4291 twins (including both members of 1647 pairs) from the Virginia Adult Study of Psychiatric and Substance Use Disorders. Exploratory factor analysis and twin model fitting were performed using, respectively, Mplus and Mx. Phenotypic factor analysis produced evidence for two correlated factors: aggressive-disregard and disinhibition. The best-fitting multivariate twin model included two genetic and one unique environmental common factor, along with criteria-specific genetic and environmental effects. The two genetic factors closely resembled the phenotypic factors and varied in their prediction of a range of relevant criterion variables. Scores on the genetic aggressive-disregard factor score were more strongly associated with risk for conduct disorder, early and heavy alcohol use, and low educational status, whereas scores on the genetic disinhibition factor score were more strongly associated with younger age, novelty seeking, and major depression. From a genetic perspective, the DSM-IV criteria for ASPD do not reflect a single dimension of liability but rather are influenced by two dimensions of genetic risk reflecting aggressive-disregard and disinhibition. The phenotypic structure of the ASPD criteria results largely from genetic and not from environmental influences. Copyright © 2012 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  4. Shared genetic effects between hepatic steatosis and fibrosis: A prospective twin study

    Science.gov (United States)

    Cui, Jeffrey; Chen, Chi-Hua; Lo, Min-Tzu; Schork, Nicholas; Bettencourt, Ricki; Gonzalez, Monica P; Bhatt, Archana; Hooker, Jonathan; Shaffer, Katherine; Nelson, Karen E; Long, Michelle T; Brenner, David A; Sirlin, Claude B; Loomba, Rohit

    2016-01-01

    Introduction Nonalcoholic fatty liver disease (NAFLD) is associated with metabolic risk factors including hypertension and dyslipidemia, and may progress to liver fibrosis. Previous studies have shown that hepatic steatosis and fibrosis are heritable but whether they have a significant shared gene effect is unknown. This study aimed to examine the shared gene effects between hepatic steatosis, fibrosis, and their associations with metabolic risk factors. Methods This is a cross-sectional analysis of a prospective cohort of well-characterized, community-dwelling twins (45 monozygotic, 20 dizygotic twin pairs, 130 total subjects) from Southern California. Hepatic steatosis was assessed with MRI-proton density fat fraction (MRI-PDFF) and hepatic fibrosis was assessed with magnetic resonance elastography (MRE). A standard bivariate twin AE model was used to estimate the proportion of phenotypic variance between two phenotypes accounted for by additive genetic effects (A) and individual-specific environmental effects (E). Genetic correlations (rG) estimated from this model represent the degree to which the genetic determinants of two phenotypes overlap. Results The mean (±SD) age and BMI were 47.1 (±21.9) years and 26.9 (±6.5) kg/m2, respectively. 20% (26/130) of the cohort had hepatic steatosis (MRI-PDFF ≥5%) and 8.2% (10/122) had hepatic fibrosis (MRE ≥3Kpa). Blood pressure (systolic and diastolic), triglycerides, glucose, homeostatic model assessment of insulin resistance (HOMA-IR), insulin, hemoglobin A1c (HbA1c), and low high-density lipoprotein (HDL) had significant shared gene effects with hepatic steatosis. Triglycerides, glucose, HOMA-IR, insulin, HbA1c, and low HDL had significant shared gene effects with hepatic fibrosis. Hepatic steatosis and fibrosis had a highly significant shared gene effect of 0.756 (95% CI: 0.716–1, psteatosis pathogenesis may also be involved with fibrosis pathogenesis. PMID:27315352

  5. The heritability of insomnia progression during childhood/adolescence: results from a longitudinal twin study.

    Science.gov (United States)

    Barclay, Nicola L; Gehrman, Philip R; Gregory, Alice M; Eaves, Lindon J; Silberg, Judy L

    2015-01-01

    To determine prevalence and heritability of insomnia during middle/late childhood and adolescence; examine longitudinal associations in insomnia over time; and assess the extent to which genetic and environmental factors on insomnia remain stable, or whether new factors come into play, across this developmental period. Longitudinal twin study. Academic medical center. There were 739 complete monozygotic twin pairs (52%) and 672 complete dizygotic twin pairs (48%) initially enrolled and were followed up at three additional time points (waves). Mode ages at each wave were 8, 10, 14, and 15 y (ages ranged from 8-18 y). None. Clinical ratings of insomnia symptoms were assessed using the Child and Adolescent Psychiatric Assessment (CAPA) by trained clinicians, and rated according to Diagnostic and Statistical Manual of Mental Disorders (DSM)-III-R criteria for presence of 'clinically significant insomnia', over four sequential waves. Insomnia symptoms were prevalent but significantly decreased across the four waves (ranging from 16.6% to 31.2%). 'Clinically significant insomnia' was moderately heritable at all waves (h² range = 14% to 38%), and the remaining source of variance was the nonshared environment. Multivariate models indicated that genetic influences at wave 1 contributed to insomnia at all subsequent waves, and that new genetic influences came into play at wave 2, which further contributed to stability of symptoms. Nonshared environmental influences were time-specific. Insomnia is prevalent in childhood and adolescence, and is moderately heritable. The progression of insomnia across this developmental time period is influenced by stable as well as new genetic factors that come into play at wave 2 (modal age 10 y). Molecular genetic studies should now identify genes related to insomnia progression during childhood and adolescence. © 2014 Associated Professional Sleep Societies, LLC.

  6. A national Swedish longitudinal twin-sibling study of criminal convictions from adolescence through early adulthood.

    Science.gov (United States)

    Kendler, Kenneth S; Lönn, Sara Larsson; Maes, Hermine H; Morris, Nancy A; Lichtenstein, Paul; Sundquist, Jan; Sundquist, Kristina

    2015-06-01

    Prior twin and adoption studies have demonstrated the importance of both genetic and shared environmental factors in the etiology of criminal behavior (CB). However, despite substantial interest in life-course theories of CB, few genetically informative studies have examined CB in a developmental context. In 69,767 male-male twin pairs and full-sibling pairs with ≤ 2 years' difference in age, born 1958-1976 and ascertained from the Swedish Twin and Population Registries, we obtained information on all criminal convictions from 1973 to 2011 from the Swedish Crime Register. We fitted a Cholesky structural model, using the OpenMx package, to CB in these pairs over three age periods: 15-19, 20-24, and 25-29. The Cholesky model had two main genetic factors. The first began at ages 15-19 and declined in importance over development. The second started at ages 20-24 and was stable over time. Only one major shared environmental factor was seen, beginning at ages 15-19. Heritability for CB declined from ages 15-29, as did shared environmental effects, although at a slower rate. Genetic risk factors for CB in males are developmentally dynamic, demonstrating both innovation and attenuation. These results are consistent with theories of adolescent-limited and life-course persistent CB subtypes. Heritability for CB did not increase over time as might be predicted from active gene-environmental correlation. However, consistent with expectation, the proportion of variability explained by shared environmental effects declined slightly as individuals aged and moved away from their original homes and neighborhoods.

  7. Genetic overlap between impulsivity and alcohol dependence: a large-scale national twin study.

    Science.gov (United States)

    Khemiri, L; Kuja-Halkola, R; Larsson, H; Jayaram-Lindström, N

    2016-04-01

    Alcohol dependence is associated with increased levels of impulsivity, but the genetic and environmental underpinnings of this overlap remain unclear. The purpose of the current study was to investigate the degree to which genetic and environmental factors contribute to the overlap between alcohol dependence and impulsivity. Univariate and bivariate twin model fitting was conducted for alcohol dependence and impulsivity in a national sample of 16 819 twins born in Sweden from 1959 to 1985. The heritability estimate for alcohol dependence was 44% [95% confidence interval (CI) 31-57%] for males and 62% (95% CI 52-72%) for females. For impulsivity, the heritability was 33% (95% CI 30-36%) in males and females. The bivariate twin analysis indicated a statistically significant genetic correlation between alcohol dependence and impulsivity of 0.40 (95% CI 0.23-0.58) in males and 0.20 (95% CI 0.07-0.33) in females. The phenotypic correlation between alcohol dependence and impulsivity was 0.20 and 0.17 for males and females, respectively, and the bivariate heritability was 80% (95% CI 47-117%) for males and 53% (95% CI 19-86%) for females. The remaining variance in all models was accounted for by non-shared environmental factors. The association between alcohol dependence and impulsivity can be partially accounted for by shared genetic factors. The genetic correlation was greater in men compared with women, which may indicate different pathways to the development of alcohol dependence between sexes. The observed genetic overlap has clinical implications regarding treatment and prevention, and partially explains the substantial co-morbidity between alcohol dependence and psychiatric disorders characterized by impulsive behaviour.

  8. Fetal Environment Is a Major Determinant of the Neonatal Blood Thyroxine Level: Results of a Large Dutch Twin Study.

    Science.gov (United States)

    Zwaveling-Soonawala, Nitash; van Beijsterveldt, Catharina E M; Mesfum, Ertirea T; Wiedijk, Brenda; Oomen, Petra; Finken, Martijn J J; Boomsma, Dorret I; van Trotsenburg, A S Paul

    2015-06-01

    The interindividual variability in thyroid hormone function parameters is much larger than the intraindividual variability, suggesting an individual set point for these parameters. There is evidence to suggest that environmental factors are more important than genetic factors in the determination of this individual set point. This study aimed to quantify the effect of genetic factors and (fetal) environment on the early postnatal blood T4 concentration. This was a classical twin study comparing the resemblance of neonatal screening blood T4 concentrations in 1264 mono- and 2566 dizygotic twin pairs retrieved from the population-based Netherlands Twin Register. Maximum-likelihood estimates of variance explained by genetic and environmental influences were obtained by structural equation modeling in data from full-term and preterm twin pairs. In full-term infants, genetic factors explained 40%/31% of the variance in standardized T4 scores in boys/girls, and shared environment, 27%/22%. The remaining variance of 33%/47% was due to environmental factors not shared by twins. For preterm infants, genetic factors explained 34%/0% of the variance in boys/girls, shared environment 31%/57%, and unique environment 35%/43%. In very preterm twins, no significant contribution of genetic factors was observed. Environment explains a large proportion of the resemblance of the postnatal blood T4 concentration in twin pairs. Because we analyzed neonatal screening results, the fetal environment is the most likely candidate for these environmental influences. Genetic influences on the T4 set point diminished with declining gestational age, especially in girls. This may be due to major environmental influences such as immaturity and nonthyroidal illness in very preterm infants.

  9. Neonatal status of twins

    Directory of Open Access Journals (Sweden)

    Božinović Dragica

    2012-01-01

    Full Text Available Multiple pregnancy is a pregnancy where more than one fetus develops simultaneously in the womb, as a result of the ovulation and fertilization of more than one egg. It is relatively rare in humans and represents the rest of the phylogenetic stages. The most common are twins and they indicate the development of two fetuses in the womb. The frequency of twin pregnancies is about 1%. Multiple pregnancies belong to a group of high-risk pregnancies because of the many complications that occur during the pregnancy: higher number of premature deliveries, bleeding, early neonatal complications and higher perinatal morbidity and mortality. Such pregnancies and infants require greater supervision and monitoring. The aim of this study was to determine the percentage of baby twins born at the maternity ward of the General Hospital in Prokuplje and their morbidity and mortality. Data on the total number of deliveries, number of twins, parity and maternal age, gestational age, body weight of twins, method of delivery, Apgar score and perinatal mortality were collected and statistically analyzed by means of retrospective analysis of operative birth and neonatal protocol for 6 years (2005 of 2010. Out of 4527 mothers who gave birth 43 were pairs of twins, or 0.95% of women gave birth to twins. These babies are more likely born by Caesarean section, but delivered with slightly lower birth weight.

  10. Socioeconomic status and number of children among Korean women: the Healthy Twin Study.

    Science.gov (United States)

    Kim, Jinseob; Sung, Joohon

    2013-01-01

    This study aimed to evaluate whether the birth rate is associated with socioeconomic status in the women of the Republic of Korea, where the birth rate is rapidly decreasing. This study included 732 females from the Healthy Twin Study, a family-twin cohort. The participants were classified into 3 socioeconomic groups according to their average income, education, and occupation. The association between socioeconomic status and number of children was assessed using gamma regression analysis with a generalized linear mixed model, adjusting for the age group, smoking/alcohol status, and family relationships. The group with the highest education level had significantly fewer children compared with the group with the lowest education level (p=0.004). However, no significant associations were found according to household income level. The non-manual labor group had significantly fewer children compared with those working as homemakers (p=0.008). This study aimed to explain the causal relationship between socioeconomic status and number of children. Associations between some socioeconomic status and number of children were found in Korea.

  11. The seroprevalence of antithyroid peroxidase antibodies in bipolar families and bipolar twins: results from two longitudinal studies.

    Science.gov (United States)

    Snijders, G; de Witte, L; Mesman, E; Kemner, S; Vonk, R; Brouwer, R; Nolen, W A; Drexhage, H A; Hillegers, M H J

    2017-12-01

    Previous studies of our group among bipolar offspring and bipolar twins showed significant higher prevalence's and levels of antithyroid peroxidase antibodies (TPO-Abs) in offspring and co-twins (without a mood disorder) compared to controls, suggesting that TPO-Abs might be considered as vulnerability factor (trait marker) for BD development. Here we elucidate, in the same cohorts, but now after 12- and 6-year follow-up, whether TPO-abs should be considered as a 'trait' marker for BD. The present study aims to investigate whether TPO-Abs (1) are stable over time, (2) are associated with lithium-exposure, (3) share a common genetic background with BD and are related to psychopathology. In bipolar offspring and twins, the prevalence of TPO-Abs is stable over time (r s  = .72 p bipolar offspring (10,4% versus 4%) and higher TPO-abs titers were still present in co-twins of bipolar cases compared to control twins [mean 1.06 IU/ml (SD .82) versus mean .82 IU/ml (SD .67)], although statistical significance was lost. Although our results show a trend toward an increased inherited risk of the co-occurrence of BD and thyroid autoimmunity, large-scale studies can only draw final conclusions. Nationwide epidemiological and GWAS studies reach such numbers and support the view of a possible common (autoimmune) etiology of severe mood disorders and chronic recurrent infections and autoimmunity, including thyroid autoimmunity.

  12. Twin-twin transfusion syndrome - diagnosis and prognosis

    Directory of Open Access Journals (Sweden)

    Hajrić-Egić Amira

    2003-01-01

    Full Text Available Twin-twin transfusion syndrome is a serious complication of monozygotic, monochorionic, diamniotic twins resulting from transplacental vascular communications. In this syndrome blood is thought to be shunted from one twin - donor,who develops anaemia,growth retardation and oligoamnios, to the other twin - recipient,who becomes plethoric,macrosomic and develops polyhydroamnios. The incidence of twin-twin transfusion syndrome ranges from 5-15% of all twin pregnancies. If this condition develops in the second trimester, it is usually associated with spontaneous abortion and death of one or both fetuses before viability. Developing the syndrome in the third trimester has better perinatal outcome. Mortality rates ranging from 56%-100%, depending on gestational age and severity of the syndrome. The ultrasound criterias for diagnosis, in this study,were the presence of twins of the same sex with discordant growth, with oligohydroamnios in one twin sac and polyhydroamnios in the other one, one placenta and thin membrane between twins. The present study shows clinical course of 14 cases and value of Doppler ultrasound to analyze the usefulness of umbilical artery blood flow velocimetry for predicting the risk of twin-twin transfusion syndrome. 14 twin pregnancies with twin-twin transfusion syndrome were diagnosed during the last four years period and prospectivelly followed. 9 cases were diagnosed before the completion od 28 weeks of gestation.The mean gestational age was 21,6_+4,2 weeks at diagnosis and 23,2+_3,6 weeks at delivery. 5 cases were diagnosed after 28 weeks of gestation. The mean gestational age in this group was 29,6+_2,1 weeks at diagnosis and 33+_3,3 weeks at delivery. The survival rate in this study was 29%(8/28.9 cases ended in spontaneous abortion between 18th and 27th weeks of pregnancy (table 1 and 5 in premature labor (table 2.There were 7 intrauterine death (5 at admission and 2 few days after admission and 13 neonatal deaths

  13. Twin studies of schizophrenia: from bow-and-arrow concordances to star wars Mx and functional genomics.

    Science.gov (United States)

    Cardno, A G; Gottesman, I I

    2000-01-01

    Twin studies have been vital for establishing an important genetic contribution to the etiology of schizophrenia. The five newest studies since 1995 from Europe and Japan have confirmed earlier findings. They yielded probandwise concordance rates of 41-65% in monozygotic (MZ) pairs and 0-28% in dizygotic (DZ) pairs, and heritability estimates of approximately 80-85%. Twin studies are also valuable for investigating the etiological relationships between schizophrenia and other disorders, and the genetic basis of clinical heterogeneity within schizophrenia. Studies of discordant MZ pairs provide further insights into non-inherited factors that contribute to the multifactorial etiology of this disorder. More recently, twin studies have begun to be used to directly investigate molecular genetic and epigenetic processes underlying schizophrenia. Copyright 2000 Wiley-Liss, Inc.

  14. Twin's Birth-Order Differences in Height and Body Mass Index From Birth to Old Age: A Pooled Study of 26 Twin Cohorts Participating in the CODATwins Project.

    Science.gov (United States)

    Yokoyama, Yoshie; Jelenkovic, Aline; Sund, Reijo; Sung, Joohon; Hopper, John L; Ooki, Syuichi; Heikkilä, Kauko; Aaltonen, Sari; Tarnoki, Adam D; Tarnoki, David L; Willemsen, Gonneke; Bartels, Meike; van Beijsterveldt, Toos C E M; Saudino, Kimberly J; Cutler, Tessa L; Nelson, Tracy L; Whitfield, Keith E; Wardle, Jane; Llewellyn, Clare H; Fisher, Abigail; He, Mingguang; Ding, Xiaohu; Bjerregaard-Andersen, Morten; Beck-Nielsen, Henning; Sodemann, Morten; Song, Yun-Mi; Yang, Sarah; Lee, Kayoung; Jeong, Hoe-Uk; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Burt, S Alexandra; Klump, Kelly L; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Harris, Jennifer R; Brandt, Ingunn; Nilsen, Thomas Sevenius; Craig, Jeffrey M; Saffery, Richard; Ji, Fuling; Ning, Feng; Pang, Zengchang; Dubois, Lise; Boivin, Michel; Brendgen, Mara; Dionne, Ginette; Vitaro, Frank; Martin, Nicholas G; Medland, Sarah E; Montgomery, Grant W; Magnusson, Patrik K E; Pedersen, Nancy L; Aslan, Anna K Dahl; Tynelius, Per; Haworth, Claire M A; Plomin, Robert; Rebato, Esther; Rose, Richard J; Goldberg, Jack H; Rasmussen, Finn; Hur, Yoon-Mi; Sørensen, Thorkild I A; Boomsma, Dorret I; Kaprio, Jaakko; Silventoinen, Karri

    2016-04-01

    We analyzed birth order differences in means and variances of height and body mass index (BMI) in monozygotic (MZ) and dizygotic (DZ) twins from infancy to old age. The data were derived from the international CODATwins database. The total number of height and BMI measures from 0.5 to 79.5 years of age was 397,466. As expected, first-born twins had greater birth weight than second-born twins. With respect to height, first-born twins were slightly taller than second-born twins in childhood. After adjusting the results for birth weight, the birth order differences decreased and were no longer statistically significant. First-born twins had greater BMI than the second-born twins over childhood and adolescence. After adjusting the results for birth weight, birth order was still associated with BMI until 12 years of age. No interaction effect between birth order and zygosity was found. Only limited evidence was found that birth order influenced variances of height or BMI. The results were similar among boys and girls and also in MZ and DZ twins. Overall, the differences in height and BMI between first- and second-born twins were modest even in early childhood, while adjustment for birth weight reduced the birth order differences but did not remove them for BMI.

  15. Craniofacial morphology in Chinese female twins: a semi-longitudinal cephalometric study.

    Science.gov (United States)

    Peng, Jing; Deng, Hui; Cao, CaiFang; Ishikawa, Masaaki

    2005-12-01

    It would be of benefit to have a better understanding of the relative effects of genetics and environmental factors on craniofacial parameters when undertaking orthodontic therapy and treatment planning. However, there is a lack of such information in pre-adolescents. The aim of this study was to verify the degree of genetic and environmental contribution to the growth of the facial skeleton in twins aged 6 to 12 years. The material comprised the lateral cephalograms of 89 pairs of female twins in Beijing, China, of whom 61 pairs were diagnosed by DNA analysis as monozygotic (MZ) and 28 pairs as dizygotic (DZ). Four main groups (with a starting age of 6, 7, 9 and 11 years) were studied in a semi-longitudinal manner, with a sub-group further investigated for 2-4 consecutive years. The total sample therefore consisted of 183 pairs (MZ 110, DZ 73) aged from 6 to 12 years. The depths of the cranial base, mid and lower face were measured, as well as anterior and posterior face height. A two-tailed t-test showed significant environmental effects on lower face depth (P < 0.01), whilst genetic effects on face height were also significant (P < 0.01). The results suggest that early orthodontic intervention would have a greater influence on the antero-posterior rather than on the vertical plane of growth.

  16. Associations Between Adiposity and Metabolic Syndrome Over Time: The Healthy Twin Study.

    Science.gov (United States)

    Song, Yun-Mi; Sung, Joohon; Lee, Kayoung

    2017-04-01

    We evaluated the association between changes in adiposity traits including anthropometric and fat mass indicators and changes in metabolic syndrome traits including metabolic syndrome clustering and individual components over time. We also assessed the shared genetic and environmental correlations between the two traits. Participants were 284 South Korean twin individuals and 279 nontwin family members had complete data for changes in adiposity traits and metabolic syndrome traits of the Healthy Twin study. Mixed linear model and bivariate variance-component analysis were applied. Over a period of 3.1 ± 0.6 years of study, changes in adiposity traits [body mass index (BMI), waist circumference, total fat mass, and fat mass to lean mass ratio] had significant associations with changes in metabolic syndrome clustering [high blood pressure, high serum glucose, high triglycerides (TG), and low high-density lipoprotein cholesterol] after adjusting for intra-familial and sibling correlations, age, sex, baseline metabolic syndrome clustering, and socioeconomic factors and health behaviors at follow-up. Change in BMI associated significantly with changes in individual metabolic syndrome components compared to other adiposity traits. Change in metabolic syndrome component TG was a better predictor of changes in adiposity traits compared to changes in other metabolic components. These associations were explained by significant environmental correlations but not by genetic correlations. Changes in anthropometric and fat mass indicators were positively associated with changes in metabolic syndrome clustering and those associations appeared to be regulated by environmental influences.

  17. The Genetic and Environmental Contributions to Internet Use and Associations With Psychopathology: A Twin Study.

    Science.gov (United States)

    Long, Elizabeth C; Verhulst, Brad; Neale, Michael C; Lind, Penelope A; Hickie, Ian B; Martin, Nicholas G; Gillespie, Nathan A

    2016-02-01

    Excessive internet use has been linked to psychopathology. Therefore, understanding the genetic and environmental risks underpinning internet use and their relation to psychopathology is important. This study aims to explore the genetic and environmental etiology of internet use measures and their associations with internalizing disorders and substance use disorders. The sample included 2,059 monozygotic (MZ) and dizygotic (DZ) young adult twins from the Brisbane Longitudinal Twin Study (BLTS). Younger participants reported more frequent internet use, while women were more likely to use the internet for interpersonal communication. Familial aggregation in 'frequency of internet use' was entirely explained by additive genetic factors accounting for 41% of the variance. Familial aggregation in 'frequency of use after 11 pm', 'using the internet to contact peers', and 'using the internet primarily to access social networking sites' was attributable to varying combinations of additive genetic and shared environmental factors. In terms of psychopathology, there were no significant associations between internet use measures and major depression (MD), but there were positive significant associations between 'frequency of internet use' and 'frequency of use after 11 pm' with social phobia (SP). 'Using the internet to contact peers' was positively associated with alcohol abuse, whereas 'using the internet to contact peers' and 'using the internet primarily to access social networking sites' were negatively associated with cannabis use disorders and nicotine symptoms. Individual differences in internet use can be attributable to varying degrees of genetic and environmental risks. Despite some significant associations of small effect, variation in internet use appears mostly unrelated to psychopathology.

  18. Psychopathic Personality and Negative Parent-to-Child Affect: A Longitudinal Cross-lag Twin Study

    Science.gov (United States)

    Tuvblad, Catherine; Bezdjian, Serena; Raine, Adrian; Baker, Laura A.

    2013-01-01

    Purpose Previous studies that have explored the relationship between parenting style and children’s antisocial behavior have generally found significant bidirectional effects, whereby parenting behaviors influence their child’s antisocial outcomes, but a child’s behaviors also lead to changes in parenting style. Methods The present study investigated the genetic and environmental underpinnings of the longitudinal relationship between negative parent-to-child affect and psychopathic personality in a sample of 1,562 twins. Using a biometrical cross-lag analysis, bidirectional effects were investigated across two waves of assessment when the twins were ages 9–10 and 14–15, utilizing both caregiver and youth self-reports. Results Results demonstrated that negative parental affects observed at ages 9–10 influenced the child’s later psychopathic personality at ages 14–15, based on both caregiver and youth self-reports. For these ‘parent-driven effects’, both genetic and non-shared environmental factors were important in the development of later psychopathic personality during adolescence. There were additional ‘child-driven effects’ such that children’s psychopathic personality at ages 9–10 influenced negative parent-to-child affect at ages 14–15, but only within caregiver reports. Conclusions Thus, children’s genetically influenced psychopathic personality seemed to evoke parental negativity at ages 14–15, highlighting the importance of investigating bidirectional effects in parent-child relationships to understand the development of these traits. PMID:24223446

  19. Effect of birth order on neonatal morbidity and mortality among very low birthweight twins: a population based study

    Science.gov (United States)

    Shinwell, E; Blickstein, I; Lusky, A; Reichman, B

    2004-01-01

    Objective: To study the effect of birth order on the risk for respiratory distress syndrome (RDS), chronic lung disease (CLD), adverse neurological findings, and death in very low birthweight (VLBW; < 1500 g) twins. Methods: A population based study of VLBW infants from the Israel National VLBW Infant Database. The sample included all complete sets of VLBW twin pairs admitted to all 28 neonatal intensive care units between 1995 and 1999. Outcome variables were compared by birth order and stratified by mode of delivery and gestational age, using General Estimating Equation models, with results expressed as odds ratio (OR) with 95% confidence interval (CI). Results: Second twins were at increased risk for RDS (OR 1.51, 95% CI 1.29 to 1.76), CLD (OR 1.36, 95% CI 1.11 to 1.66), and death (OR 1.24, 95% CI 1.02 to 1.51) but not for adverse neurological findings (OR 1.20, 95% CI 0.91 to 1.60). Mode of delivery did not significantly influence outcome. The odds ratio for RDS in the second twin was inversely related to gestational age, and the increased risk for RDS and CLD was found in both vaginal and caesarean deliveries. Conclusions: VLBW second twins are at increased risk for acute and chronic lung disease and neonatal mortality, irrespective of mode of delivery. PMID:14977899

  20. Genetic and Environmental Influences on Motor Function: A Magnetoencephalographic Study of Twins

    OpenAIRE

    Araki, Toshihiko; Hirata, Masayuki; Sugata, Hisato; Yanagisawa, Takufumi; Onishi, Mai; Watanabe, Yoshiyuki; Omura, Kayoko; Honda, Chika; Hayakawa, Kazuo; Yorifuji, Shiro

    2014-01-01

    To investigate the effect of genetic and environmental influences on cerebral motor function, we determined similarities and differences of movement-related cortical fields (MRCFs) in middle-aged and elderly monozygotic (MZ) twins. MRCFs were measured using a 160-channel magnetoencephalogram system when MZ twins were instructed to repeat lifting of the right index finger. We compared latency, amplitude, dipole location, and dipole intensity of movement-evoked field 1 (MEF1) between 16 MZ twin...

  1. Parent-child feedback predicts sibling contrast: using twin studies to test theories of parent-offspring interaction in infant behavior.

    Science.gov (United States)

    Eaves, Lindon J; Silberg, Judy L

    2005-02-01

    Several studies report apparent sibling contrast effects in analyses of twin resemblance. In the presence of genetic differences, contrast effects reduce the dizygotic (DZ) twin correlation relative to that in monozygotic (MZ) twins and produce higher DZ than MZ variance. Explanations of contrast effects are typically cast in terms of direct social interaction between twins or an artifact of the process of rating children by their parents. We outline a model for sibling imitation and contrast effects that depends on social interaction between parents and children. In addition to predicting the observed pattern of twin variances and covariances, the parental mediation of child imitation and contrast effects leads to differences in the variance of parents of MZ and DZ twins and differences between the correlations of parents with their MZ and DZ children.

  2. The relationship between avoidant personality disorder and social phobia: a population-based twin study.

    Science.gov (United States)

    Reichborn-Kjennerud, Ted; Czajkowski, Nikolai; Torgersen, Svenn; Neale, Michael C; Ørstavik, Ragnhild E; Tambs, Kristian; Kendler, Kenneth S

    2007-11-01

    The purpose of this study was to determine the sources of comorbidity for social phobia and dimensional representations of avoidant personality disorder by estimating to what extent the two disorders are influenced by common genetic and shared or unique environmental factors versus the extent to which these factors are specific to each disorder. Young adult female-female twin pairs (N=1,427) from the Norwegian Institute of Public Health Twin Panel were assessed at personal interview for avoidant personality disorder and social phobia using the Structured Interview for DSM-IV Personality and the Composite International Diagnostic Interview. Bivariate Cholesky models were fitted using the Mx statistical program. The best-fitting model included additive genetic and unique environmental factors only. Avoidant personality disorder and social phobia were influenced by the same genetic factors, whereas the environmental factors influencing the two disorders were uncorrelated. Within the limits of statistical power, these results suggest that there is a common genetic vulnerability to avoidant personality disorder and social phobia in women. An individual with high genetic liability will develop avoidant personality disorder versus social phobia entirely as a result of the environmental risk factors unique to each disorder. The results are in accordance with the hypothesis that psychobiological dimensions span the axis I and axis II disorders.

  3. The contribution of endogenous and exogenous factors to male alopecia: a study of identical twins.

    Science.gov (United States)

    Gatherwright, James; Liu, Mengyuan T; Amirlak, Bardia; Gliniak, Christy; Totonchi, Ali; Guyuron, Bahman

    2013-05-01

    The purpose of this study was to investigate the potential contribution of environmental factors and testosterone on male alopecia. Ninety-two identical male twins were recruited from 2009 to 2011. A comprehensive questionnaire was completed followed by the acquisition of sputum samples for testosterone analysis and standardized digital photography. Frontal, temporal, and vertex hair loss was assessed from these photographs. Hair loss was then correlated with survey responses and testosterone levels between twin pairs. Two independent, blinded observers also rated the photographs for hair thinning. Increased smoking duration (p money spent on hair loss products (p = 0.050) were all associated with increased temporal hair loss. Daily hat use (p = 0.050), higher body mass index (p = 0.012), and higher testosterone levels (p = 0.040) were associated with decreased temporal hair loss. Factors that were significantly associated with increased vertex hair loss included abstinence from alcohol consumption (p = 0.030), consumption of more than four alcoholic drinks per week (p = 0.004), increased smoking duration (p = 0.047), increased exercise duration (p = 0.050), and increased stress duration (p = 0.010). Lower body mass index, more children, increased caffeine consumption, history of skin disease, and abstinence from alcohol were significantly associated with increased hair thinning scores (p exogenous factors may have a clinically significant impact on hair loss. Risk, III.

  4. Temporomandibular disorder-type pain and migraine headache in women: a preliminary twin study.

    Science.gov (United States)

    Plesh, Octavia; Noonan, Carolyn; Buchwald, Dedra S; Goldberg, Jack; Afari, Niloo

    2012-01-01

    To determine whether shared genetic influences are responsible for the association between pain from temporomandibular disorders (TMD) and migraine headache. Data were obtained from 1,236 monozygotic and 570 dizygotic female twin pairs from the University of Washington Twin Registry. TMD pain was assessed with a question about persistent or recurrent pain in the jaw, temple, in front of the ear, or in the ear. The presence of migraine headache was determined by self-report of doctor-diagnosed migraine. Univariate and bivariate structural equation models estimated the components of variance attributable to genetic and environmental influences. The best fitting univariate models indicated that additive genetic effects contributed 27% of the variance in TMD pain (95% confidence interval = 15% to 38%) and 49% of the variance in migraine headache (95% confidence interval = 40% to 57%). The best-fitting bivariate model revealed that 12% of the genetic component of TMD pain is shared with migraine headache. These preliminary findings suggest that the association between TMD pain and migraine headache in women may be partially due to a modest shared genetic risk for both conditions. Future studies can focus on replicating these findings with symptom- and diagnosis-based instruments.

  5. Study of grain structure evolution during annealing of a twin-roll-cast Mg alloy

    International Nuclear Information System (INIS)

    Tripathi, A.; Samajdar, I.; Nie, J.F.; Tewari, A.

    2016-01-01

    The evolution of microstructure under static annealing was studied for mid-thickness section of a twin-roll-cast (TRC) magnesium alloy. Annealing was performed at 300 °C and 500 °C for different times. Microstructural evolution was quantitatively analyzed, from optical micrographs, using grain path envelope analysis. Additional information from electron backscatter diffraction (EBSD) was used for addressing the possible mechanism(s). It was found that the TRC structure had a bimodal grain size, which was preserved even after annealing at 300 °C. However, the annealing at 500 °C led to a unimodal grain size. This difference in the grain size distribution created a contrasting behavior in the normalized standard deviations. This was primarily attributed to a competition between recovery and recrystallization, and their respective dominance at 300° and 500 °C. A deformation induced recrystallization recovery (DIRR) model was proposed. The proposed model could successfully address the experimental microstructural evolution. - Highlights: • Annealing of twin roll cast (TRC) magnesium alloy was done at temperatures of 300 °C and 500 °C. • TRC had bimodal structure. Bimodality preserved for annealing at 300 °C. Annealing at 500 °C led to unimodal structure. • Grain evolution was described based on the competition between recovery and recrystallization. • Deformation induced recrystallization recovery (DIRR) mechanistic model was developed.

  6. Shared Genetics of Temporomandibular Disorder Pain and Neck Pain: Results of a Twin Study.

    Science.gov (United States)

    Visscher, Corine M; Schouten, Maarten J; Ligthart, Lannie; van Houtem, Caroline Mhh; de Jongh, Ad; Boomsma, Dorret I

    2018-03-06

    (1) To examine the heritability of TMD pain and of neck pain; and (2) to estimate the potential overlap in genetic and environmental factors influencing TMD pain and neck pain. Data from 2,238 adult female twins who completed a survey on TMD pain and neck pain were analyzed. The total variance of TMD pain and neck pain was decomposed into variance attributable to additive genetic effects and nonshared environmental effects. Bivariate structural equation modeling was applied to estimate trait-specific and genetic effects shared between traits. The prevalence of TMD pain and neck pain was 8.6% and 46.8%, respectively, while 6.7% of the twins reported both TMD pain and neck pain. The phenotypic correlation between TMD pain and neck pain, based on a liability threshold model, was 0.43 (95% confidence interval [CI] 0.34 to 0.51). The heritability for TMD was 0.35 (0.17 to 0.51), and for neck pain was 0.33 (0.23 to 0.43). The genetic correlation between TMD pain and neck pain was 0.64 (0.35 to 1.00), and the environmental correlation was 0.32 (0.14 to 0.48). This study shows that variation in TMD pain and neck pain can in part be attributed to genes. The comorbidity between them is partly explained by genes that influence both traits and partly by the same environmental factors.

  7. Heritability of DUI convictions: a twin study of driving under the influence of alcohol.

    Science.gov (United States)

    Anum, Emmanuel A; Silberg, Judy; Retchin, Sheldon M

    2014-02-01

    The study was undertaken to assess the relative contributions of genetic and environmental influences on drunk-driving. Driving records of a cohort of male and female twins (N = 17,360) from the Mid-Atlantic Twin Registry were examined. Structural equation models were used to estimate the magnitude of genetic and environmental effects on male and female phenotypes, and test for gender differences. There were significant gender and age effects. Compared with females, males were five times more likely to engage in driving under the influence. Among persons aged 21-49 years, the risk for drunk-driving was eight times that for those aged 50+ years and five times greater than those ≤20 years. In both males and females, aged 21-49 years, a large proportion (57%) of the variance in drunk-driving was due to genetic factors and the remaining 43% due to individual specific environmental influences. Drunk-driving is under significant genetic influence in both males and females. Our findings suggest that a different set of genes influence DUIs in men and women.

  8. Molecular dynamics simulation of albite twinning and pericline twinning in low albite

    International Nuclear Information System (INIS)

    Li, Bin; Knowles, Kevin M

    2013-01-01

    Two twinning laws, the albite law and the pericline law, are the predominant growth twinning modes in triclinic plagioclase feldspars such as low albite, NaAlSi 3 O 8 , in which the aluminum and silicon atoms are in an ordered arrangement on the tetrahedral sites of the aluminosilicate framework. In the terminology used formally to describe deformation twinning in a triclinic lattice, these twin laws can be described as Type I and Type II twin laws, respectively, with the pericline twin law being conjugate to the albite twin law. In this study, twin boundaries have been constructed for low albite according to these two twinning laws and studied by molecular dynamics simulation. The results show that suitably constructed twin boundary models are quite stable for both albite twinning and pericline twinning during molecular dynamics simulation. The calculated twin boundary energy of an albite twin is significantly lower than that of a pericline twin, in accord with the experimental observation that albite twinning is the more commonly observed mode seen in plagioclase feldspars. The results of the molecular dynamics simulations also agree with conclusions from the prior work of Starkey that glide twinning in low albite is not favoured energetically. (paper)

  9. Does the sex of one’s co-twin affect height and BMI in adulthood? A study of dizygotic adult twins from 31 cohorts

    DEFF Research Database (Denmark)

    Bogl, Leonie H; Jelenkovic, Aline; Vuoksimaa, Eero

    2017-01-01

    Background: The comparison of traits in twins from opposite-sex (OS) and same-sex (SS) dizygotic twin pairs is considered a proxy measure of prenatal hormone exposure. To examine possible prenatal hormonal influences on anthropometric traits, we compared mean height, body mass index (BMI), and th...

  10. Long term costs and effects of reducing the number of twin pregnancies in IVF by single embryo transfer: the TwinSing study

    NARCIS (Netherlands)

    van Heesch, M.M.J.; Bonsel, G.J.; Dumoulin, J.C.M.; Evers, J.L.H.; van der Hoeven, M.A.H.B.; Severens, J.L.; Dykgraaf, R.H.M.; van der Veen, F.; Tonch, N.; Nelen, W.L.D.M.; van Zonneveld, P.; van Goudoever, J.B.; Tamminga, P.; Steiner, K.; Koopman-Esseboom, C.; van Beijsterveldt, C.E.M.; Boomsma, D.I.; Snellen, D.; Dirksen, C.D.

    2010-01-01

    Background: Pregnancies induced by in vitro fertilisation (IVF) often result in twin gestations, which are associated with both maternal and perinatal complications. An effective way to reduce the number of IVF twin pregnancies is to decrease the number of embryos transferred from two to one. The

  11. Does the sex of one's co-twin affect height and BMI in adulthood? : A study of dizygotic adult twins from 31 cohorts

    NARCIS (Netherlands)

    Bogl, Leonie H; Jelenkovic, Aline; Vuoksimaa, Eero; Ahrenfeldt, Linda; Pietiläinen, Kirsi H; Stazi, Maria A; Fagnani, Corrado; D'Ippolito, Cristina; Hur, Yoon-Mi; Jeong, Hoe-Uk; Silberg, Judy L; Eaves, Lindon J; Maes, Hermine H; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Cutler, Tessa L; Kandler, Christian; Jang, Kerry L; Christensen, Kaare; Skytthe, Axel; Kyvik, Kirsten Ohm; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; Derom, Catherine A; Vlietinck, Robert F; Nelson, Tracy L; Whitfield, Keith E; Corley, Robin P; Huibregtse, Brooke M; McAdams, Tom A; Eley, Thalia C; Gregory, Alice M; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Willemsen, Gonneke; Bartels, Meike; Pang, Zengchang; Tan, Qihua; Zhang, Dongfeng; Martin, Nicholas G; Medland, Sarah E; Montgomery, Grant W; Hjelmborg, Jacob V B; Rebato, Esther; Swan, Gary E; Krasnow, Ruth; Busjahn, Andreas; Lichtenstein, Paul; Öncel, Sevgi Y; Aliev, Fazil; Baker, Laura A; Tuvblad, Catherine; Siribaddana, Sisira H; Hotopf, Matthew; Sumathipala, Athula; Rijsdijk, Fruhling; Magnusson, Patrik K E; Pedersen, Nancy L; Aslan, Anna K Dahl; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Duncan, Glen E; Buchwald, Dedra; Tarnoki, Adam D; Tarnoki, David L; Yokoyama, Yoshie; Hopper, John L; Loos, Ruth J F; Boomsma, Dorret I; Sørensen, Thorkild I A; Silventoinen, Karri; Kaprio, Jaakko; van Beijsterveldt, C.E.M.

    2017-01-01

    BACKGROUND: The comparison of traits in twins from opposite-sex (OS) and same-sex (SS) dizygotic twin pairs is considered a proxy measure of prenatal hormone exposure. To examine possible prenatal hormonal influences on anthropometric traits, we compared mean height, body mass index (BMI), and the

  12. Sleep disruption, chronotype, shift work, and prostate cancer risk and mortality: a 30-year prospective cohort study of Finnish twins.

    Science.gov (United States)

    Dickerman, Barbra A; Markt, Sarah C; Koskenvuo, Markku; Hublin, Christer; Pukkala, Eero; Mucci, Lorelei A; Kaprio, Jaakko

    2016-11-01

    Sleep disruption and shift work have been associated with cancer risk, but epidemiologic evidence for prostate cancer remains limited. We aimed to prospectively investigate the association between midlife sleep- and circadian-related parameters and later prostate cancer risk and mortality in a population-based cohort of Finnish twins. Data were drawn from the Older Finnish Twin Cohort and included 11,370 twins followed from 1981 to 2012. Over the study period, 602 incident cases of prostate cancer and 110 deaths from prostate cancer occurred. Cox regression was used to evaluate associations between midlife sleep duration, sleep quality, chronotype, and shift work with prostate cancer risk and prostate cancer-specific mortality. Within-pair co-twin analyses were employed to account for potential familial confounding. Compared to "definite morning" types, "somewhat evening" types had a significantly increased risk of prostate cancer (HR 1.3; 95 % CI 1.1, 1.6). Chronotype significantly modified the relationship between shift work and prostate cancer risk (p-interaction shift work and prostate cancer risk in the overall analyses and no significant association between any sleep- or circadian-related parameter and risk in co-twin analyses. Neither sleep- nor circadian-related parameters were significantly associated with prostate cancer-specific mortality. The association between sleep disruption, chronotype, and shift work with prostate cancer risk and mortality has never before been studied in a prospective study of male twins. Our findings suggest that chronotype may be associated with prostate cancer risk and modify the association between shift work and prostate cancer risk. Future studies of circadian disruption and prostate cancer should account for this individual-level characteristic.

  13. Experimental studies on twin PTCs driven by dual piston head linear compressor

    Science.gov (United States)

    Gour, Abhay S.; Joy, Joewin; Sagar, Pankaj; Sudharshan, H.; Mallappa, A.; Karunanithi, R.; Jacob, S.

    2017-02-01

    An experimental study on pulse tube cryocooler is presented with a twin pulse tube configuration. The study is conducted with a dual piston head linear compressor design which is developed indigenously. The two identical pulse tube cryocoolers are operated by a single linear motor which generates 1800 out of phase dual pressure waves. The advantages of the configuration being the reduction in fabrication cost and the increased cooling power. The compressor is driven at a frequency of 48 Hz using indigenously developed PWM based power supply. The CFD study of pulse tube cryocooler is discussed along with the experimental cool down results. A detailed experimental and FEM based studies on the fabrication procedure of heat exchangers is conducted to ensure better heat transfer in the same.

  14. Genetic regulation of pre-pubertal development of body mass index: a longitudinal study of Japanese twin boys and girls.

    Science.gov (United States)

    Silventoinen, Karri; Kaprio, Jaakko; Yokoyama, Yoshie

    2011-03-01

    We analyzed the genetic architecture of prepubertal development of relative weight to height in 216 monozygotic and 159 dizygotic complete Japanese twin pairs (52% girls). Ponderal index at birth (kg/m(3)) and body mass index (BMI, kg/m(2)) from 1 to 11 years of age were used. Additive genetic factors explained the major proportion (52-74%) of the variation of BMI from 1 to 11 years of age. Environmental factors common to both co-twins also showed some effect (7-28%), but at most ages this was not statistically significant. Strong genetic tracking was found for BMI from 1 to 11 years of age, but there was also evidence for a persistent effect of common environmental factors. Our results suggest that the genetic architecture of BMI development in the Japanese population is generally similar to that found in previous twin studies in Caucasian populations.

  15. Playing a Musical Instrument as a Protective Factor against Dementia and Cognitive Impairment: A Population-Based Twin Study.

    Science.gov (United States)

    Balbag, M Alison; Pedersen, Nancy L; Gatz, Margaret

    2014-01-01

    Increasing evidence supports that playing a musical instrument may benefit cognitive development and health at young ages. Whether playing an instrument provides protection against dementia has not been established. In a population-based cotwin control study, we examined the association between playing a musical instrument and whether or not the twins developed dementia or cognitive impairment. Participation in playing an instrument was taken from informant-based reports of twins' leisure activities. Dementia diagnoses were based on a complete clinical workup using standard diagnostic criteria. Among 157 twin pairs discordant for dementia and cognitive impairment, 27 pairs were discordant for playing an instrument. Controlling for sex, education, and physical activity, playing a musical instrument was significantly associated with less likelihood of dementia and cognitive impairment (odds ratio [OR] = 0.36 [95% confidence interval 0.13-0.99]). These findings support further consideration of music as a modifiable protective factor against dementia and cognitive impairment.

  16. The Spread of Substance Use and Delinquency between Adolescent Twins

    Science.gov (United States)

    Laursen, Brett; Hartl, Amy C.; Vitaro, Frank; Brendgen, Mara; Dionne, Ginette; Boivin, Michel

    2017-01-01

    This investigation examines the spread of problem behaviors (substance use and delinquency) between twin siblings. A sample of 628 twins (151 male twin pairs and 163 female twin pairs) drawn from the Quebec Newborn Twin Study completed inventories describing delinquency and substance use at ages 13, 14, and 15. A 3-wave longitudinal actor-partner…

  17. A Twin Study of Objective and Subjective Pubertal Timing and Peer Influence on Risk-Taking.

    Science.gov (United States)

    Kretsch, Natalie; Mendle, Jane; Harden, K Paige

    2016-03-01

    The current study used a behavioral genetic design to test whether three measures of pubertal timing moderated peer influence on risk-taking in a sample of 248 female adolescent twin pairs ( M age =16.0, SD =1.5) from the National Longitudinal Study of Adolescent Health. Peer influence was operationalized as the quasi-causal association between girls' self-reported risk-taking and the risk-taking reported by their friends. Girls with earlier ages at menarche and who perceived themselves as more developed than peers were more susceptible to peer influence on risk-taking. However, age-standardized ratings of body changes did not moderate peer influence. This study highlights distinctions between multiple measures of pubertal timing, using an innovative synthesis of genetically informative data and peer nomination data.

  18. Twin Studies in Autism: What Might They Say about Genetic and Environmental Influences

    Science.gov (United States)

    Anderson, George M.

    2012-01-01

    Genetic and epigenetic differences exist within monozygote twin-pairs and might be especially important in the expression of autism. Assuming phenotypic differences between monozygotic twins are due to environmental influences may lead to mistaken conclusions regarding the relative genetic and environmental contribution to autism risk.

  19. Examination of the Relationship between Oral Health and Arterial Sclerosis without Genetic Confounding through the Study of Older Japanese Twins.

    Directory of Open Access Journals (Sweden)

    Yuko Kurushima

    Full Text Available Although researchers have recently demonstrated a relationship between oral health and arterial sclerosis, the genetic contribution to this relationship has been ignored even though genetic factors are expected to have some effect on various diseases. The aim of this study was to evaluate oral health as a significant risk factor related to arterial sclerosis after eliminating genetic confounding through study of older Japanese twins.Medical and dental surveys were conducted individually for 106 Japanese twin pairs over the age of 50 years. Maximal carotid intima-media thickness (IMT-Cmax was measured as a surrogate marker of arterial sclerosis. IMT-Cmax > 1.0 mm was diagnosed as arterial sclerosis. All of the twins were examined for the number of remaining teeth, masticatory performance, and periodontal status. We evaluated each measurement related with IMT-Cmax and arterial sclerosis using generalized estimating equations analysis adjusted for potential risk factors. For non-smoking monozygotic twins, a regression analysis using a "between within" model was conducted to evaluate the relationship between IMT-Cmax and the number of teeth as the environmental factor controlling genetic and familial confounding.We examined 91 monozygotic and 15 dizygotic twin pairs (males: 42, females: 64 with a mean (± standard deviation age of 67.4 ± 10.0 years. Out of all of the oral health-related measurements collected, only the number of teeth was significantly related to arterial sclerosis (odds ratio: 0.72, 95% confidence interval: 0.52-0.99 per five teeth. Regression analysis showed a significant association between the IMT-Cmax and the number of teeth as an environmental factor (p = 0.037.Analysis of monozygotic twins older than 50 years of age showed that having fewer teeth could be a significant environmental factor related to arterial sclerosis, even after controlling for genetic and familial confounding.

  20. Febrile Seizures and Epilepsy: Association With Autism and Other Neurodevelopmental Disorders in the Child and Adolescent Twin Study in Sweden.

    Science.gov (United States)

    Gillberg, Christopher; Lundström, Sebastian; Fernell, Elisabeth; Nilsson, Gill; Neville, Brian

    2017-09-01

    There is a recently well-documented association between childhood epilepsy and earlysymptomaticsyndromeselicitingneurodevelopmentalclinicalexaminations (ESSENCE) including autism spectrum disorder, but the relationship between febrile seizures and ESSENCE is less clear. The Child and Adolescent Twin Study in Sweden (CATSS) is an ongoing population-based study targeting twins born in Sweden since July 1, 1992. Parents of 27,092 twins were interviewed using a validated DSM-IV-based interview for ESSENCE, in connection with the twins' ninth or twelfth birthday. Diagnoses of febrile seizures (n = 492) and epilepsy (n = 282) were based on data from the Swedish National Patient Register. Prevalence of ESSENCE in individuals with febrile seizures and epilepsy was compared with prevalence in the twin population without seizures. The association between febrile seizures and ESSENCE was considered before and after adjustment for epilepsy. Age of diagnosis of febrile seizures and epilepsy was considered as a possible correlate of ESSENCE in febrile seizures and epilepsy. The rate of ESSENCE in febrile seizures and epilepsy was significantly higher than in the total population without seizures (all P epilepsy, a significant association between febrile seizures and autism spectrum disorder, developmental coordination disorder, and intellectual disability remained. Earlier age of onset was associated with all ESSENCE except attention-deficit/hyperactivity disorder in epilepsy but not with ESSENCE in febrile seizures. In a nationally representative sample of twins, there was an increased rate of ESSENCE in childhood epilepsy and in febrile seizures. Febrile seizures alone could occur as a marker for a broader ESSENCE phenotype. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Can middle cerebral artery peak systolic velocity predict polycythemia in monochorionic-diamniotic twins? Evidence from a prospective cohort study.

    Science.gov (United States)

    Fishel-Bartal, M; Weisz, B; Mazaki-Tovi, S; Ashwal, E; Chayen, B; Lipitz, S; Yinon, Y

    2016-10-01

    The antenatal diagnosis of twin anemia-polycythemia sequence (TAPS) in monochorionic-diamniotic (MCDA) twin pregnancies is based on elevated peak systolic velocity in the middle cerebral artery (MCA-PSV) in the donor twin and decreased MCA-PSV in the recipient twin. However, the association between these parameters and polycythemia has not yet been established. The aim of this study was to determine whether MCA-PSV can predict polycythemia in MCDA pregnancies. This was a prospective cohort study of MCDA pregnancies recruited at 14-18 weeks' gestation from a single tertiary care center between January 2011 and June 2014. Fetal MCA Doppler waveforms were recorded every 2 weeks from 18 weeks' gestation until delivery. Only those with an MCA-PSV measurement within 1 week of delivery were included in the analysis. Neonatal hematocrit level was determined in all twins from venous blood obtained within 4 h of delivery. Polycythemia was defined as a hematocrit of > 65%, and anemia as a hematocrit of  8 g/dL and reticulocyte count ratio of > 1.7 were observed. Of 162 MCDA pregnancies followed during the study period, 69 had an MCA-PSV measurement within 1 week of delivery and were included in the study. Twenty-five neonates were diagnosed with polycythemia and nine twin pairs met the criteria for TAPS. In a pooled analysis, MCA-PSV was negatively correlated with neonatal hematocrit (P = 0.017, r = -0.215) and was significantly higher in anemic fetuses than in normal controls (1.15 multiples of the median (MoM) vs 1.02 MoM, respectively; P = 0.001). However, MCA-PSV was similar among polycythemic and normal fetuses (0.95 MoM vs 1.02 MoM, respectively; P = 0.47). Intertwin difference in MCA-PSV (delta MCA-PSV) was positively correlated with intertwin hematocrit difference (P = 0.002, r = 0.394). Moreover, twin pregnancies with an intertwin hematocrit difference of > 24% had a significantly greater delta MCA-PSV than did those with an intertwin hematocrit

  2. Fuzzy Controller Design Using Evolutionary Techniques for Twin Rotor MIMO System: A Comparative Study

    Directory of Open Access Journals (Sweden)

    H. A. Hashim

    2015-01-01

    Full Text Available This paper presents a comparative study of fuzzy controller design for the twin rotor multi-input multioutput (MIMO system (TRMS considering most promising evolutionary techniques. These are gravitational search algorithm (GSA, particle swarm optimization (PSO, artificial bee colony (ABC, and differential evolution (DE. In this study, the gains of four fuzzy proportional derivative (PD controllers for TRMS have been optimized using the considered techniques. The optimization techniques are developed to identify the optimal control parameters for system stability enhancement, to cancel high nonlinearities in the model, to reduce the coupling effect, and to drive TRMS pitch and yaw angles into the desired tracking trajectory efficiently and accurately. The most effective technique in terms of system response due to different disturbances has been investigated. In this work, it is observed that GSA is the most effective technique in terms of solution quality and convergence speed.

  3. Heritability and environmental effects for self-reported periods with stuttering: A twin study from Denmark

    DEFF Research Database (Denmark)

    Fagnani, Corrado; Fibiger, Steen; Skytthe, Axel

    2011-01-01

    Genetic influence for stuttering was studied based on adult self-reporting. Using nation-wide questionnaire answers from 33,317 Danish twins, a univariate biometric analysis based on the liability threshold model was performed in order to estimate the heritability of stuttering. The self......-reported incidences for stuttering were from less than 4% for females to near 9% for males. Both probandwise concordance rate and tetrachoric correlation were substantially higher for monozygotic compared to dizygotic pairs, indicating substantial genetic influence on individual liability. Univariate biometric...... analyses showed that additive genetic and unique environmental factors best explained the observed concordance patterns. Heritability estimates for males/females were 0.84/0.81. Moderate unique environmental effects were also found. Genetic influence for stuttering was studied based on adult self...

  4. Genetic and environmental influences on the comorbidity between depression, panic disorder, agoraphobia and social phobia: A twin study

    Science.gov (United States)

    Mosing, Miriam A.; Gordon, Scott D.; Medland, Sarah E.; Statham, Dixie J.; Nelson, Elliot C.; Heath, Andrew C.; Martin, Nicholas G.; Wray, Naomi R.

    2011-01-01

    Background Major depression (MD) and anxiety disorders such as panic disorder (PD), agoraphobia (AG) and social phobia (SP) are heritable and highly comorbid. However, the relative importance of genetic and environmental aetiology of the covariation between these disorders, particularly the relationship between PD and AG is less clear. Methods The present study measured MD, PD and AG in a population sample of 5440 twin pairs and 1245 single twins, about 45% of whom were also scored for SP. Prevalences, within individual comorbidity and twin odds ratios for comorbidity are reported. A behavioural genetic analysis of the four disorders using the classical twin design was conducted. Results Odds ratios for MD, PD, AG, and SP in twins of individuals diagnosed with one of the four disorders were increased. Heritability estimates under a threshold-liability model for MD, PD, AG, and SP respectively were 0.33 (CI:0.30–0.42), 0.38 (CI:0.24–0.55), 0.48 (CI:0.37–0.65) of, and 0.39 (CI:0.16–0.65), with no evidence for any variance explained by the common environment shared by twins. We find that a common genetic factor explains a moderate proportion of variance in these four disorders. The genetic correlation between PD and AG was 0.83. Conclusion MD, PD, AG, and SP strongly co-aggregate within families and common genetic factors explain a moderate proportion of variance in these four disorders. The high genetic correlation between PD and AG and the increased odds ratio for PD and AG in siblings of those with AG without PD suggests a common genetic aetiology for PD and AG. PMID:19750555

  5. Genetic and environmental influences on the co-morbidity between depression, panic disorder, agoraphobia, and social phobia: a twin study.

    Science.gov (United States)

    Mosing, Miriam A; Gordon, Scott D; Medland, Sarah E; Statham, Dixie J; Nelson, Elliot C; Heath, Andrew C; Martin, Nicholas G; Wray, Naomi R

    2009-01-01

    Major depression (MD) and anxiety disorders such as panic disorder (PD), agoraphobia (AG), and social phobia (SP) are heritable and highly co-morbid. However, the relative importance of genetic and environmental etiology of the covariation between these disorders, particularly the relationship between PD and AG, is less clear. This study measured MD, PD, and AG in a population sample of 5,440 twin pairs and 1,245 single twins, about 45% of whom were also scored for SP. Prevalences, within individual co-morbidity and twin odds ratios for co-morbidity, are reported. A behavioral genetic analysis of the four disorders using the classical twin design was conducted. Odds ratios for MD, PD, AG, and SP in twins of individuals diagnosed with one of the four disorders were increased. Heritability estimates under a threshold-liability model for MD, PD, AG, and SP respectively were .33 (CI: 0.30-0.42), .38 (CI: 0.24-0.55), .48 (CI: 0.37-0.65), and .39 (CI: 0.16-0.65), with no evidence for any variance explained by the common environment shared by twins. We find that a common genetic factor explains a moderate proportion of variance in these four disorders. The genetic correlation between PD and AG was .83. MD, PD, AG, and SP strongly co-aggregate within families and common genetic factors explain a moderate proportion of variance in these four disorders. The high genetic correlation between PD and AG and the increased odds ratio for PD and AG in siblings of those with AG without PD suggests a common genetic etiology for PD and AG.

  6. Road traffic noise and registry based use of sleep medication.

    NARCIS (Netherlands)

    Evandt, Jorunn; Oftedal, Bente; Krog, Norun Hjertager; Skurtveit, Svetlana; Nafstad, Per; Schwarze, Per E; Skovlund, Eva; Houthuijs, Danny; Aasvang, Gunn Marit

    2017-01-01

    Road traffic noise has been associated with adverse health effects including sleep disturbances. Use of sleep medication as an indicator of sleeping problems has rarely been explored in studies of the effects of traffic noise. Furthermore, using registry data on sleep medications provides an

  7. The Heritability of Macular Response to Supplemental Lutein and Zeaxanthin: A Classic Twin Study

    Science.gov (United States)

    Hammond, Christopher J.; Liew, S. H. Melissa; Van Kuijk, Frederik J.; Beatty, Stephen; Nolan, John M.; Spector, Tim D.; Gilbert, Clare E.

    2012-01-01

    Purpose. Antioxidant supplements may reduce age-related macular degeneration (AMD) progression. The macular carotenoids are of particular interest because of their biochemical, optical, and anatomic properties. This classic twin study was designed to determine the heritability of macular pigment (MP) augmentation in response to supplemental lutein (L) and zeaxanthin (Z). Methods. A total of 322 healthy female twin volunteers, aged 16–50 years (mean 40 ± 8.7) was enrolled in a prospective, nonrandomized supplement study. Macular pigment optical density (MPOD) measurements using two techniques (2-wavelength fundus autofluorescence [AF] and heterochromatic flicker photometry [HFP]), and serum concentrations of L and Z, were recorded at baseline, and at 3 and 6 months following daily supplementation with 18 mg L and 2.4 mg Z for a study period of 6 months. Results. At baseline, mean MPOD was 0.44 density units (SD 0.21, range 0.04–1.25) using HFP, and 0.41 density units (SD 0.15) using AF. Serum L and Z levels were raised significantly from baseline following 3 months' supplementation (mean increase 223% and 633%, respectively, P < 0.0001 for both), with no MPOD increase. After 6 months' supplementation, a small increase in MPOD was seen (mean increase 0.025 ± 0.16, P = 0.02, using HFP). Subdivision of baseline MPOD into quartiles revealed that baseline levels made no difference to the treatment effect. Genetic factors explained 27% (95% confidence interval [CI] 7–45) of the variation in MPOD response. Distribution profiles of macular pigment did not change in response to supplementation. Conclusions. MPOD response to supplemental L and Z for a period of 6 months was small (an increase over baseline of 5.7% and 3.7%, measured using HFP and AF, respectively), and was moderately heritable. Further study is indicated to investigate the functional and clinical impact of supplementation with the macular carotenoids. PMID:22700713

  8. Genetic and developmental factors in spontaneous selective attention: a study of normal twins.

    Science.gov (United States)

    Myles-Worsley, M; Coon, H

    1997-08-08

    The Spontaneous Selective Attention Task (SSAT) is a visual word identification task designed to measure the type of selective attention that occurs spontaneously when there are multiple stimuli, all potentially relevant, and insufficient time to process each of them fully. These are conditions which are common in everyday life. SSAT performance is measured by word identification accuracy, first under a baseline divided attention condition with no predictability, then under a selective attention condition with partial predictability introduced via word repetition. Accuracy to identify novel words in the upper location which becomes partially predictable (P words) vs. the lower location which remains non-predictable (N words) can be used to calculate a baseline performance index and a P/N ratio measure of selective attention. The SSAT has been shown to identify an attentional abnormality that may be useful in the development of an attentional endophenotype for family-genetic studies of schizophrenia. This study examined age and genetic effects on SSAT performance in normal children in order to evaluate whether the SSAT has the potential to qualify as a candidate endophenotype for schizophrenia in studies of at-risk children. A total of 59 monozygotic twin pairs and 33 same-sex dizygotic twin pairs ranging from 10 to 18 years of age were tested on the SSAT, a Continuous Performance Test. (CPT), a Span of Apprehension Test (SPAN) and a full-scale IQ test. Baseline performance on the SSAT, which was correlated with verbal IQ and SPAN performance, improved with age but showed no significant heritability. The P/N selectivity ratio was stable over the 10-18-year age range, was not significantly correlated with IQ, CPT, or SPAN performance, and its heritability was estimated to be 0.41. These findings suggest that the P/N selectivity ratio measured by the SSAT may be useful as a vulnerability marker in studies of children born into families segregating schizophrenia.

  9. Heritability and confirmation of genetic association studies for childhood asthma in twins.

    Science.gov (United States)

    Ullemar, V; Magnusson, P K E; Lundholm, C; Zettergren, A; Melén, E; Lichtenstein, P; Almqvist, C

    2016-02-01

    Although the genetics of asthma has been extensively studied using both quantitative and molecular genetic analysis methods, both approaches lack studies specific to the childhood phenotype and including other allergic diseases. This study aimed to give specific estimates for the heritability of childhood asthma and other allergic diseases, to attempt to replicate findings from genomewide association studies (GWAS) for childhood asthma and to test the same variants against other allergic diseases. In a cohort of 25 306 Swedish twins aged 9 or 12 years, data on asthma were available from parental interviews and population-based registers. The interviews also inquired about wheeze, hay fever, eczema, and food allergy. Through structural equation modeling, the heritability of all phenotypes was calculated. A subset of 10 075 twins was genotyped for 16 single nucleotide polymorphisms (SNPs) selected from previous GWAS; these were first tested for association with asthma and significant findings also against the other allergic diseases. The heritability of any childhood asthma was 0.82 (95% CI 0.79-0.85). For the other allergic diseases, the range was approximately 0.60-0.80. Associations for six SNPs with asthma were replicated, including rs2305480 in the GSDMB gene (OR 0.80, 95% CI 0.74-0.86, P = 1.5*10(-8) ; other significant associations all below P = 3.5*10(-4) ). Of these, only rs3771180 in IL1RL1 was associated with any other allergic disease (for hay fever, OR 0.64, 95% CI 0.53-0.77, P = 2.5*10(-6) ). Asthma and allergic diseases of childhood are highly heritable, and these high-risk genetic variants associated specifically with childhood asthma, except for one SNP shared with hay fever. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Twin Pregnancy with Gastroschisis in Both Twins

    Directory of Open Access Journals (Sweden)

    Hui-Fen Kao

    2007-12-01

    Conclusion: The cause of gastroschisis is unknown, although possible exogenous causes have been studied. The diagnosis of gastroschisis in twin pregnancy is always in late gestation. Therefore, maternal serum alpha feto-protein screening and a detailed prenatal ultrasound evaluation are recommended in multifetal pregnancies.

  11. Seasonal genetic influence on serum 25-hydroxyvitamin D levels: a twin study.

    Directory of Open Access Journals (Sweden)

    Greta Snellman

    Full Text Available BACKGROUND: Although environmental factors, mainly nutrition and UV-B radiation, have been considered major determinants of vitamin D status, they have only explained a modest proportion of the variation in serum 25-hydroxyvitamin D. We aimed to study the seasonal impact of genetic factors on serum 25-hydroxyvitamin D concentrations. METHODOLOGY/PRINCIPAL FINDINGS: 204 same-sex twins, aged 39-85 years and living at northern latitude 60 degrees, were recruited from the Swedish Twin Registry. Serum 25-hydroxyvitamin D was analysed by high-pressure liquid chromatography and mass spectrometry. Genetic modelling techniques estimated the relative contributions of genetic, shared and individual-specific environmental factors to the variation in serum vitamin D. The average serum 25-hydroxyvitamin D concentration was 84.8 nmol/l (95% CI 81.0-88.6 but the seasonal variation was substantial, with 24.2 nmol/l (95% CI 16.3-32.2 lower values during the winter as compared to the summer season. Half of the variability in 25-hydroxyvitamin D during the summer season was attributed to genetic factors. In contrast, the winter season variation was largely attributable to shared environmental influences (72%; 95% CI 48-86%, i.e., solar altitude. Individual-specific environmental influences were found to explain one fourth of the variation in serum 25-hydroxyvitamin D independent of season. CONCLUSIONS/SIGNIFICANCE: There exists a moderate genetic impact on serum vitamin D status during the summer season, probably through the skin synthesis of vitamin D. Further studies are warranted to identify the genes impacting on vitamin D status.

  12. The heritability and genetic correlates of mobile phone use: a twin study of consumer behavior.

    Science.gov (United States)

    Miller, Geoffrey; Zhu, Gu; Wright, Margaret J; Hansell, Narelle K; Martin, Nicholas G

    2012-02-01

    There has been almost no overlap between behavior genetics and consumer behavior research, despite each field's importance in understanding society. In particular, both have neglected to study genetic influences on consumer adoption and usage of new technologies -- even technologies as important as the mobile phone, now used by 5.8 out of 7.0 billion people on earth. To start filling this gap, we analyzed self-reported mobile phone use, intelligence, and personality traits in two samples of Australian teenaged twins (mean ages 14.2 and 15.6 years), totaling 1,036 individuals. ACE modeling using Mx software showed substantial heritabilities for how often teens make voice calls (.60 and .34 in samples 1 and 2, respectively) and for how often they send text messages (.53 and. 50). Shared family environment - including neighborhood, social class, parental education, and parental income (i.e., the generosity of calling plans that parents can afford for their teens) -- had much weaker effects. Multivariate modeling based on cross-twin, cross-trait correlations showed negative genetic correlations between talking/texting frequency and intelligence (around -.17), and positive genetic correlations between talking/texting frequency and extraversion (about .20 to .40). Our results have implications for assessing the risks of mobile phone use such as radiofrequency field (RF) exposure and driving accidents, for studying adoption and use of other emerging technologies, for understanding the genetic architecture of the cognitive and personality traits that predict consumer behavior, and for challenging the common assumption that consumer behavior is shaped entirely by culture, media, and family environment.

  13. Associations of Mother's and Father's Parenting Practices with Children's Observed Social Reticence in a Competitive Situation: A Monozygotic Twin Difference Study

    Science.gov (United States)

    Guimond, Fanny-Alexandra; Brendgen, Mara; Forget-Dubois, Nadine; Dionne, Ginette; Vitaro, Frank; Tremblay, Richard E.; Boivin, Michel

    2012-01-01

    This study used the monozygotic (MZ) twin difference method to examine whether the unique environmental effects of maternal and paternal overprotection and hostility at the age of 30 months predict twins' observed social reticence in a competitive situation in kindergarten, while controlling for the effect of family-wide influences, including…

  14. The Influence of Chorion Type on Health Measures at Birth and Dental Development in Australian and Dutch Twins: A Comparative Study

    NARCIS (Netherlands)

    Mihailidis, S.; Bockmann, M.; McConnell, E.; Hughes, T.; van Beijsterveldt, C.E.M.; Boomsma, D.I.; McMaster, M.T.; Townsend, G.

    2015-01-01

    Chorion type may significantly influence the prenatal environment of twins. This study explored the associations between chorion type and gestational age, birth weight, birth length, and the timing of emergence of the first primary tooth in two populations of twins, Australian and Dutch.

  15. The Association between Persistent Disruptive Childhood Behaviour and the Psychopathic Personality Constellation in Adolescence: A Twin Study

    Science.gov (United States)

    Forsman, Mats; Larsson, Henrik; Andershed, Henrik; Lichtenstein, Paul

    2007-01-01

    This study tested if persistent externalizing behaviour and symptoms of Attention Deficit Hyperactivity Disorder (ADHD) in childhood are associated with personality and behavioural aspects of the psychopathic personality constellation in adolescence. The target sample consisted of all 1,480 twin pairs born in Sweden between 1985 and 1986.…

  16. Identical, Fraternal, or Separated at Birth: A Case Study of Educator Teams within American-Israeli School Twinning

    Science.gov (United States)

    Chertok, Fern; Mittelberg, David; Laron, Dinah; Koren, Annette

    2013-01-01

    School-to-school collaboration has emerged as a key paradigm for fostering personal and institutional connections between Israeli and Diaspora youth, educators, and schools. Using the findings of a multi-year case study of a high school level twinning initiative, this article describes the challenges to this form of transnational collaboration and…

  17. Circulating microRNAs disclose biology of normal cognitive function in healthy elderly people – a discovery twin study

    DEFF Research Database (Denmark)

    Mengel-From, Jonas; Feddersen, Søren; Halekoh, Ulrich

    2018-01-01

    Neurobiology is regulated by miRNA. Here circulating plasma miRNAs were assayed on a 754 miRNA OpenArray platform using 90 monozygotic elderly twins (73–95 year of age) and associated with mini mental state examination (MMSE) and a five-component cognitive score (CCS) in an explorative study. Bot...

  18. Genetic and social influences on starting to smoke: a study of Dutch adolescent twins and their parents

    NARCIS (Netherlands)

    Boomsma, D.I.; Koopmans, J.R.; van Doornen, L.J.P.; Orlebeke, J.F.

    1994-01-01

    In a study of 1600 Dutch adolescent twin pairs we found that 59% of the inter‐individual variation in smoking behaviour could be attributed to shared environmental influences and 31% to genetic factors. The magnitude of the genetic and environmental effects did not differ between boys and girls.

  19. Maternal obesity in singleton versus twin gestations: a population-based matched case-control study.

    Science.gov (United States)

    Lucovnik, Miha; Blickstein, Isaac; Verdenik, Ivan; Trojner-Bregar, Andreja; Tul, Natasa

    2015-04-01

    To examine the impact of pre-pregnancy obesity on adverse outcomes in twin compared to singleton pregnancies. Dichorionic twin gestations with maternal body mass index >30 were matched to three singleton controls. Both obese groups were matched (1:3) with non-obese controls. Rates of preeclampsia, gestational diabetes, cesarean section, and preterm birth were compared. One hundred eighty-nine dichorionic twin pregnancies in obese mothers were matched to 567 twin pregnancies in non-obese mothers, and to 567 singleton pregnancies in obese mothers. The latter were matched to 1701 non-obese mothers with singletons. Preeclampsia was more common in obese mothers with both twins and singletons (odds ratio (OR) 3.95, 95% confidence interval (CI) 2.18-7.16 and OR 6.53, 95% CI 3.75-11.4, respectively) as was gestational diabetes (OR 4.35, 95% CI 2.18-8.69; OR 5.53 95% CI 3.60-8.50). Obese mothers with singletons were more likely to deliver abdominally, but the cesarean rates were obesity independent in twins. Obese mothers were more likely to deliver at Obesity-attributable adverse outcomes are lower in twins compared to singletons. Obesity increases the risk of preterm birth regardless of plurality.

  20. Genetic and environmental effects on same-sex sexual behavior: a population study of twins in Sweden.

    Science.gov (United States)

    Långström, Niklas; Rahman, Qazi; Carlström, Eva; Lichtenstein, Paul

    2010-02-01

    There is still uncertainty about the relative importance of genes and environments on human sexual orientation. One reason is that previous studies employed self-selected, opportunistic, or small population-based samples. We used data from a truly population-based 2005-2006 survey of all adult twins (20-47 years) in Sweden to conduct the largest twin study of same-sex sexual behavior attempted so far. We performed biometric modeling with data on any and total number of lifetime same-sex sexual partners, respectively. The analyses were conducted separately by sex. Twin resemblance was moderate for the 3,826 studied monozygotic and dizygotic same-sex twin pairs. Biometric modeling revealed that, in men, genetic effects explained .34-.39 of the variance, the shared environment .00, and the individual-specific environment .61-.66 of the variance. Corresponding estimates among women were .18-.19 for genetic factors, .16-.17 for shared environmental, and 64-.66 for unique environmental factors. Although wide confidence intervals suggest cautious interpretation, the results are consistent with moderate, primarily genetic, familial effects, and moderate to large effects of the nonshared environment (social and biological) on same-sex sexual behavior.

  1. Genetic and environmental influences on externalizing behavior and alcohol problems in adolescence: A female twin study

    Science.gov (United States)

    Knopik, Valerie S.; Heath, Andrew C.; Bucholz, Kathleen K.; Madden, Pamela A.F.; Waldron, Mary

    2009-01-01

    Genetic and environmental contributions to the observed correlations among DSM-IV ADHD problems [inattentive (INATT) and hyperactive/impulsive (HYP/IMP) behaviors], conduct problems (CDP) and alcohol problems (AlcProb) were examined by fitting multivariate structural equation models to data from the Missouri Adolescent Female Twin Study [N=2892 twins (831 monozygotic pairs, 615 dizygotic pairs)]. Based on results of preliminary regression models, we modified the structural model to jointly estimate (i) the regression of each phenotype on significant familial/prenatal predictors, and (ii) genetic and environmental contributions to the residual variance and covariance. Results suggested that (i) parental risk factors, such as parental alcohol dependence and regular smoking, increase risk for externalizing behavior; (ii) prenatal exposures predicted increased symptomatology for HYP/IMP (smoking during pregnancy), INATT and CDP (prenatal alcohol exposure); (iii) after adjusting for measured familial/prenatal risk factors, genetic influences were significant for HYP/IMP, INATT, and CDP; however, similar to earlier reports, genetic effects on alcohol dependence symptoms were negligible; and (iv) in adolescence, correlated liabilities for conduct and alcohol problems are found in environmental factors common to both phenotypes, while covariation among impulsivity, inattention, and conduct problems is primarily due to genetic influences common to these three behaviors. Thus, while a variety of adolescent problem behaviors are significantly correlated, the structure of that association may differ as a function of phenotype (e.g., comorbid HYP/IMP and CDP vs. comorbid CDP and AlcProb), a finding that could inform different approaches to treatment and prevention. PMID:19341765

  2. Heritability of face shape in twins: a preliminary study using 3D stereophotogrammetry and geometric morphometrics

    Directory of Open Access Journals (Sweden)

    Seth M. Weinberg

    2013-11-01

    Full Text Available Introduction: Previous research suggests that aspects of facial surface morphology are heritable.  Traditionally, heritability studies have used a limited set of linear distances to quantify facial morphology and often employ statistical methods poorly designed to deal with biological shape.  In this preliminary report, we use a combination of 3D photogrammetry and landmark-based morphometrics to explore which aspects of face shape show the strongest evidence of heritability in a sample of twins. Methods: 3D surface images were obtained from 21 twin pairs (10 monozygotic, 11 same-sex dizygotic.  Thirteen 3D landmarks were collected from each facial surface and their coordinates subjected to geometric morphometric analysis.  This involved superimposing the individual landmark configurations and then subjecting the resulting shape coordinates to a principal components analysis.  The resulting PC scores were then used to calculate rough narrow-sense heritability estimates. Results: Three principal components displayed evidence of moderate to high heritability and were associated with variation in the breadth of orbital and nasal structures, upper lip height and projection, and the vertical and forward projection of the root of the nose due to variation in the position of nasion. Conclusions: Aspects of facial shape, primarily related to variation in length and breadth of central midfacial structures, were shown to demonstrate evidence of strong heritability. An improved understanding of which facial features are under strong genetic control is an important step in the identification of specific genes that underlie normal facial variation.

  3. A study of the occurrence of monochorionic and monozygotic twinning in the pig

    DEFF Research Database (Denmark)

    Bjerre, Ditte; Thorup, F.; Jørgensen, Claus Bøttcher

    2009-01-01

    the investigation of porcine monochorionic embryos from 76 sows at days 26-29 post-insemination (p.i.), as well as an examination of 10 whole litters at days 21-22 p.i. In the former group, 29% of the sows carried monochorionic embryos. Based on DNA profiling using microsatellite markers, one monozygotic twin pair...... was found among these embryos. In the latter group, three monozygotic twin pairs were identified. Thus, it can be concluded that although the occurrence of monozygotic twins in pigs is a sporadic event, the fusion of extra-embryonic membranes is relatively common....

  4. Metabolic studies in unaffected co-twins of non-insulin-dependent diabetics.

    OpenAIRE

    Barnett, A H; Spiliopoulos, A J; Pyke, D A; Stubbs, W A; Burrin, J; Alberti, K G

    1981-01-01

    Forty-eight out of 53 non-insulin-dependent diabetic identical twin pairs were concordant for diabetes. In the five discordant pairs the diabetic twin had only recently been diagnosed. Oral glucose tolerance tests were carried out on the unaffected twins of the five pairs and on matched controls. Fasting concentrations of blood glucose (5.5 +/- 0.6 v 3.7 +/- 0.3 mmol/l; 99.1 +/- 10.8 v 66.6 +/- 5.4 mg/100 ml), haemoglobin A1 (mean 9.1%, range 8.8-9.2% v mean 7.9%, range 7.4-8.4%), lactate, al...

  5. Sports pairs: insights on athletic talent; research reviews: twins with leukemia; parents and twins.

    Science.gov (United States)

    Segal, Nancy L

    2007-06-01

    Twin research exploring genetic and environmental influences on athletic interests and talents is reviewed. Illustrative examples of twin athletes representing a variety of sports activities are presented. This is followed by an overview of twin studies offering critical insights into the onset and progress of leukemia. In the last section, timely events involving twins and parents of twins will be described--each case provides a new look at an old question.

  6. Twins and non-twin siblings: different estimates of shared environmental influence in early childhood.

    Science.gov (United States)

    Koeppen-Schomerus, Gesina; Spinath, Frank M; Plomin, Robert

    2003-04-01

    Twin studies typically indicate shared environmental influence for cognitive abilities, especially in early childhood. However, across studies, DZ twin correlations tend to be greater than non-twin sibling correlations, suggesting that twin estimates of shared environment are to some extent specific to twins. We tested this hypothesis in a sample of more than 1800 MZ and 1800 same-sex DZ pairs from the Twins Early Development Study (TEDS), a study of twins born in England and Wales in 1994 and 1995. For this analysis, we obtained comparable data from more than 130 same-sex younger siblings of the twins. Twins and their younger siblings were assessed for language, cognitive abilities and behavior problems by their parents at 2 and 3 years of age. For language and cognitive measures at both 2 and 3 years, but not for behavior problems, estimates of shared environment were more than twice as large for twins as compared to non-twin siblings. We conclude that about half of twin study estimates of shared environment for cognitive abilities in early childhood are specific to twins. Although many possibilities exist for explaining the special shared environment effect for twins, we suggest that cognitive-relevant experiences that are not shared by siblings are shared by twins because they are exactly the same age.

  7. Environmental influence of problematic social relationships on adolescents' daily cortisol secretion: a monozygotic twin-difference study.

    Science.gov (United States)

    Brendgen, M; Ouellet-Morin, I; Lupien, S J; Vitaro, F; Dionne, G; Boivin, M

    2017-02-01

    This study investigated the potential environmental effects of peer victimization and the quality of relationships with parents and friends on diurnal cortisol secretion in mid-adolescence. This study used the monozygotic (MZ) twin-difference design to control for genetic effects and thus estimate the unique environmental influences on diurnal cortisol. Participants were 136 MZ twin pairs (74 female pairs) for whom cortisol was assessed four times per day over four collection days grouped in a 2-week period in grade 8 (mean age = 14.07 years). Participants also provided self-reports of peer victimization from grade 4 to grade 8 and of the relationship quality with the mother, father and best friend in grade 8. The expected pattern of diurnal cortisol secretion was observed, with high levels at awakening followed by an increase 30 min later and a progressive decrease subsequently. Controlling for a host of confounders, only within-twin pair differences in peer victimization and a problematic relationship with the mother were significantly linked to twin differences in diurnal cortisol secretion. Specifically, whereas a more problematic mother-child relationship was associated with morning cortisol secretion, peer victimization was linked to cortisol secretion later in the day (diurnal slope). Controlling for genetic influences and other confounders, stressful relationships with peers and the mother exert unique and time-specific environmental influences on the pattern of diurnal cortisol secretion in mid-adolescence.

  8. Birth order of twins and risk of perinatal death related to delivery in England, Northern Ireland, and Wales, 1994-2003: retrospective cohort study.

    Science.gov (United States)

    Smith, Gordon C S; Fleming, Kate M; White, Ian R

    2007-03-17

    To determine the effect of birth order on the risk of perinatal death in twin pregnancies. Retrospective cohort study. England, Northern Ireland, and Wales, 1994-2003. 1377 twin pregnancies with one intrapartum stillbirth or neonatal death from causes other than congenital abnormality and one surviving infant. The risk of perinatal death in the first and second twin estimated with conditional logistic regression. There was no association between birth order and the risk of death overall (odds ratio 1.0, 95% confidence interval 0.9 to 1.1). However, there was a highly significant interaction with gestational age (Pbirth order and the risk of death among infants born before 36 weeks' gestation but there was an increased risk of death among second twins born at term (2.3, 1.7 to 3.2, Pbirths, there was a trend (P=0.1) towards a greater risk of the second twin dying from anoxia among those delivered vaginally (4.1, 1.8 to 9.5) compared with those delivered by caesarean section (1.8, 0.9 to 3.6). In this cohort, compared with first twins, second twins born at term were at increased risk of perinatal death related to delivery. Vaginally delivered second twins had a fourfold risk of death caused by intrapartum anoxia.

  9. Establishing a Twin Register : An Invaluable Resource for (Behavior) Genetic, Epidemiological, Biomarker, and 'Omics' Studies

    NARCIS (Netherlands)

    Odintsova, Veronika V; Willemsen, Gonneke; Dolan, Conor V; Hottenga, Jouke-Jan; Martin, Nicholas G; Slagboom, P Eline; Ordoñana, Juan R; Boomsma, Dorret I

    2018-01-01

    Twin registers are wonderful research resources for research applications in medical and behavioral genetics, epidemiology, psychology, molecular genetics, and other areas of research. New registers continue to be launched all over the world as researchers from different disciplines recognize the

  10. Performance study of a twin-screw expander used in a geothermal organic Rankine cycle power generator

    International Nuclear Information System (INIS)

    Tang, Hao; Wu, Huagen; Wang, Xiaolin; Xing, Ziwen

    2015-01-01

    The ORC (organic Rankine cycle) system is an effective technology to generate electricity from low temperature heat sources. The twin-screw expander is a key component that is commonly used in the small-to-medium capacity ORC system to convert thermal energy into work. In this paper, the performance of a twin-screw expander is theoretically and experimentally studied. A mathematical model is developed and subsequently validated using experimental data. The effect of several important factors including expander speed, suction pressure and inlet superheat on the expander performance is investigated. Results indicate that the expander speed and suction pressure have large influences on the expander performance, while the inlet superheat has relatively small effect. The isentropic efficiency of the expander decreases from 0.88 to 0.6 and the expander volumetric efficiency decreases from 0.88 to 0.7 as the expander rotational speed increases from 1250 to 6000 rpm. The results further show that the expander volumetric efficiency decreases from 0.91 to 0.85 as the expander suction pressure increases from 0.33 to 0.47 MPa. Furthermore, the energy conversion efficiency of the studied ORC system using the twin-screw expander is as high as 7.5% under the site conditions. - Highlights: • Performance of a twin-screw expander used in an ORC (organic Rankine cycle) system was studied. • A thermodynamic model was developed for this purpose and experimentally validated. • Effect of several key factors on the expander performance was investigated. • Suction pressure has a large influence on the expander performance. • Twin-screw expanders can be operated with a wide range of heat source temperatures.

  11. Craniopagus twins: a comparative study of radiological findings and surgery (with a review of literatures)

    International Nuclear Information System (INIS)

    Yang Zhiyun; Luo Baining; Wu Xinjian

    2005-01-01

    Objective: To improve the understanding of craniopagus twins through a case report and literature review. Method: A pair of female craniopagus twins was examined with CT and MRI and angiography. The radiological findings were compared with operation. Results: The operation result was in consistent with imaging findings. Conclusion: Modern radiological modalities can evaluate complex deformity, which play an important role in the orthopedic procedures. (authors)

  12. Problem in twin pregnancy: Findings of prenatal sonography and autopsy

    International Nuclear Information System (INIS)

    Kim, Jeong Ah; Cho, Jeong Yeon; Song, Mi Jin; Min, Jee Yeon; Lee, Young Ho; Lee, Hak Jong; Chun, Yi Kyeong; Kim, Yee Jeong; Hong, Sung Ran

    2001-01-01

    Multifetal gestations are high risk pregnancies with higher perinatal morbidity and mortality. Multifetal gestations are subject to unique complications including conjoined twins, twin-to-twin transfusion syndrome (TTTS), acardiac twins, twin embization of co-twin demise and heterotopic pregnancies. Prenatal sonographic diagnosis of types and complications of multifetal gestations is important for antenatal care and prediction of fetal outcome. This study was performed to present the prenatal ultrasonographic findings and pathologic findings of the unique complications of twin pregnancy. Acardia is a lethal anomaly occurring in 1% of monozygotic twin. The acardiac twin has a parasitic existence and depends on the donor (pump) twin for its blood supply via placental anastomoses and retrograde perfusion of umbilical cord. This twin reversed arterial perfusion (TRAP) sequence is a most extreme manifestation on the TTTS. Doppler verification reversed flow in umbilical cord of the acardiac twin confirms the diagnosis.

  13. Maternal weight gain and associations with longitudinal fetal growth in dichorionic twin pregnancies: a prospective cohort study.

    Science.gov (United States)

    Hinkle, Stefanie N; Hediger, Mary L; Kim, Sungduk; Albert, Paul S; Grobman, William; Newman, Roger B; Wing, Deborah A; Grewal, Jagteshwar; Zhang, Cuilin; Buck Louis, Germaine M; Grantz, Katherine L

    2017-12-01

    Background: Maternal metabolic demands are much greater with twin gestations; however, there are no accepted recommendations for maternal weight gain in twin pregnancies. Objective: We assessed the association of maternal weight gain and fetal growth in dichorionic twins throughout pregnancy. Design: This was a prospective US cohort study ( n = 143, 2012-2013) of dichorionic twin pregnancies with known birth outcomes followed from enrollment (11-13 wk) and for ≤6 research visits throughout gestation. Maternal prepregnancy weight was self-reported, and current weight was measured at each research visit and abstracted from prenatal records. Fetal biometry was assessed by ultrasound at each research visit. Maternal weight and twin-pair fetal size trajectories across gestation were modeled. The adjusted associations between maternal weight gain from 0 to 13, 14 to 20, 21 to 27, and 28 to 34 wk and fetal growth at the subsequent week (i.e., 14, 21, 28, and 35 wk, respectively) were estimated with the use of linear regression. Results: The mean ± SD maternal weight gain from 0 to 13, 14 to 20, 21 to 27, and 28 to 34 wk was 2.8 ± 3.0 kg, 3.9 ± 1.2 kg, 3.8 ± 1.4 kg, and 4.4 ± 2.2 kg, respectively, with a total gain of 17.7 ± 7.4 kg. Maternal weight gain from 0 to 13 wk (first trimester) was not associated with fetal size at 14 wk. Maternal weight gain from 14 to 20 and 21 to 27 wk (second trimester) was significantly associated with increased fetal weight at 21 wk [increase of 10.5 g/kg maternal weight gain (95% CI: 1.2, 19.8 g)] and 28 wk [increase of 21.3 g/kg maternal weight gain (95% CI: 0.6, 42.0 g)]. Maternal weight gain from 14 to 20 wk was associated with increased twin abdominal circumference (AC) and biparietal diameter at 21 wk. Maternal weight gain from 21 to 27 wk was associated with increased femur and humerus lengths at 28 wk. Conclusion: Maternal weight gain was associated with dichorionic twin fetal growth in the second trimester only, driven by an

  14. Hypertensive disorders in twin pregnancy

    NARCIS (Netherlands)

    J.G. Santema (Job); E. Koppelaar (Elin); H.C.S. Wallenburg (Henk)

    1995-01-01

    textabstractObjective: To compare the incidence and severity of pregnancy-induced hypertensive disorders in twin pregnancy and in singleton gestation. Study design: Case-control study in the setting of a University Hospital. Each pregnancy of a consecutive series of 187 twin pregnancies attending

  15. STOPPIT Baby Follow-up Study: the effect of prophylactic progesterone in twin pregnancy on childhood outcome.

    Directory of Open Access Journals (Sweden)

    Helen Christine McNamara

    Full Text Available To determine the long-term effects of in utero progesterone exposure in twin children.This study evaluated the health and developmental outcomes of all surviving children born to mothers who participated in a double-blind, placebo-controlled trial of progesterone given for the prevention of preterm birth in twin pregnancies (STOPPIT, ISRCTN35782581. Follow-up was performed via record linkage and two parent-completed validated questionnaires, the Child Development Inventory and the Health Utilities Index.Record linkage was successfully performed on at least one record in 759/781 (97% children eligible for follow-up. There were no differences between progesterone-exposed and placebo-exposed twins with respect to incidence of death, congenital anomalies and hospitalisation, nor on routine national child health assessments. Questionnaire responses were received for 324/738 (44% children. The mean age at questionnaire follow-up was 55.5 months. Delay in at least one developmental domain on the Child Development Inventory was observed in 107/324 (33% children, with no evidence of difference between progesterone-exposed and placebo-exposed twins. There was no evidence of difference between the progesterone and placebo groups in global health status assessed using the Health Utilities Index: 89% of children were rated as having 'excellent' health and a further 8% as having 'very good' health.In this cohort of twin children there was no evidence of a detrimental or beneficial impact on health and developmental outcomes at three to six years of age due to in utero exposure to progesterone.

  16. A study of pathophysiological factors associated with gastro-esophageal reflux disease in twins discordant for gastro-esophageal reflux symptoms.

    Science.gov (United States)

    Iovino, P; Mohammed, I; Anggiansah, A; Anggiansah, R; Cherkas, L F; Spector, T D; Trudgill, N J

    2013-08-01

    Differences in lower esophageal sphincter (LES) and peristaltic function and in transient LES relaxations (TLESR) have been described in patients with gastro-esophageal reflux disease (GERD). However, some of these differences may be the result of chronic GERD rather than being an underlying contributory factor. Twins discordant for GERD symptoms, i.e., only one twin had GERD symptoms, underwent standard LES and esophageal body manometry, and then using a sleeve sensor prolonged LES and pH monitoring, 30 min before and 60 min after a 250 mL 1200 kcal lipid meal. Eight monozygotic and 24 dizygotic female twins were studied. Although there was no difference in preprandial LES pressure (symptomatic 13.2 ± 7.1 mmHg vs asymptomatic 15.1 ± 6.2 mmHg, P = 0.4), LES pressure fell further postprandially in symptomatic twins (LES pressure area under the curve 465 ± 126 vs 331 ± 141 mmHg h, P reflux episodes in symptomatic twins occurred due to low LES pressure or deep inspiration/strain and 0/17 in asymptomatic twins (P = 0.01). There was no difference between symptomatic and asymptomatic twins in: peristaltic amplitude, ineffective esophageal body motility, hiatus hernia prevalence, or LES length. There was also no difference in TLESR frequency preprandially (symptomatic median 1(range 0-2) vs asymptomatic 0(0-2), P = 0.08) or postprandially (2.5(1-8) vs 3(1-6), P = 0.81). Twins with GERD symptoms had lower postprandial LES pressure and given the close genetic link between the twins, it is possible that such differences are caused by GERD. Acid reflux episodes associated with a hypotensive LES were seen in symptomatic, but not in asymptomatic twins. © 2013 John Wiley & Sons Ltd.

  17. Genetic liability to disability pension in women and men: a prospective population-based twin study.

    Directory of Open Access Journals (Sweden)

    Jurgita Narusyte

    Full Text Available BACKGROUND: Previous studies of risk factors for disability pension (DP have mainly focused on psychosocial, or environmental, factors, while the relative importance of genetic effects has been less studied. Sex differences in biological mechanisms have not been investigated at all. METHODS: The study sample included 46,454 Swedish twins, consisting of 23,227 complete twin pairs, born 1928-1958, who were followed during 1993-2008. Data on DP, including diagnoses, were obtained from the National Social Insurance Agency. Within-pair similarity in liability to DP was assessed by calculating intraclass correlations. Genetic and environmental influences on liability to DP were estimated by applying discrete-time frailty modeling. RESULTS: During follow-up, 7,669 individuals were granted DP (18.8% women and 14.1% men. Intraclass correlations were generally higher in MZ pairs than DZ pairs, while DZ same-sexed pairs were more similar than opposite-sexed pairs. The best-fitting model indicated that genetic factors contributed 49% (95% CI: 39-59 to the variance in DP due to mental diagnoses, 35% (95% CI: 29-41 due to musculoskeletal diagnoses, and 27% (95% CI: 20-33 due to all other diagnoses. In both sexes, genetic effects common to all ages explained one-third, whereas age-specific factors almost two-thirds, of the total variance in liability to DP irrespective of diagnosis. Sex differences in liability to DP were indicated, in that partly different sets of genes were found to operate in women and men, even though the magnitude of genetic variance explained was equal for both sexes. CONCLUSIONS: The findings of the study suggest that genetic effects are important for liability to DP due to different diagnoses. Moreover, genetic contributions to liability to DP tend to differ between women and men, even though the overall relative contribution of genetic influences does not differ by sex. Hence, the pathways leading to DP might differ between women and

  18. Postpartum Mental State of Mothers of Twins

    Science.gov (United States)

    Brantmüller, Éva; Gyúró, Mónika; Galgán, Kitti; Pakai, Annamária

    2016-01-01

    Twin birth is a relevant risk factor for postnatal depression (PND). The primary objective of our study is to reveal the prevalence of suspected cases of depression and to identify some background factors among mothers of twins. We applied convenience sampling method within a retrospective, quantitative study among mothers given birth to twins for…

  19. Epigenetic Epidemiology of Complex Diseases Using Twins

    DEFF Research Database (Denmark)

    Tan, Qihua

    2013-01-01

    through multiple epigenetic mechanisms. This paper reviews the new developments in using twins to study disease-related epigenetic alterations, links them to lifetime environmental exposure with a focus on the discordant twin design and proposes novel data-analytical approaches with the aim of promoting...... a more efficient use of twins in epigenetic studies of complex human diseases....

  20. Concordance for multiple sclerosis in Danish twins

    DEFF Research Database (Denmark)

    Hansen, T; Skytthe, Axel; Stenager, Egon

    2005-01-01

    The occurrence of multiple sclerosis (MS) in twins has not previously been studied in complete nationwide data sets. The existence of almost complete MS and twin registries in Denmark ensures that essentially unbiased samples of MS cases among twins can be obtained. In this population-based study...

  1. Associations of Body Composition Measurements with Serum Lipid, Glucose and Insulin Profile: A Chinese Twin Study

    Science.gov (United States)

    Liao, Chunxiao; Gao, Wenjing; Cao, Weihua; Lv, Jun; Yu, Canqing; Wang, Shengfeng; Zhou, Bin; Pang, Zengchang; Cong, Liming; Wang, Hua; Wu, Xianping; Li, Liming

    2015-01-01

    Objectives To quantitate and compare the associations of various body composition measurements with serum metabolites and to what degree genetic or environmental factors affect obesity-metabolite relation. Methods Body mass index (BMI), waist circumference (WC), lean body mass (LBM), percent body fat (PBF), fasting serum high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglycerides (TG), total cholesterol (TC), glucose, insulin and lifestyle factors were assessed in 903 twins from Chinese National Twin Registry (CNTR). Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated from fasting serum glucose and insulin. Linear regression models and bivariate structural equation models were used to examine the relation of various body composition measurements with serum metabolite levels and genetic/environmental influences on these associations, respectively. Results At individual level, adiposity measurements (BMI, WC and PBF) showed significant associations with serum metabolite concentrations in both sexes and the associations still existed in male twins when using within-MZ twin pair comparison analyses. Associations of BMI with TG, insulin and HOMA-IR were significantly stronger in male twins compared to female twins (BMI-by-sex interaction p = 0.043, 0.020 and 0.019, respectively). Comparison of various adiposity measurements with levels of serum metabolites revealed that WC explained the largest fraction of variance in serum LDL-C, TG, TC and glucose concentrations while BMI performed best in explaining variance in serum HDL-C, insulin and HOMA-IR levels. Of these phenotypic correlations, 64–81% were attributed to genetic factors, whereas 19–36% were attributed to unique environmental factors. Conclusions We observed different associations between adiposity and serum metabolite profile and demonstrated that WC and BMI explained the largest fraction of variance in serum lipid profile and insulin

  2. From equity to power: Critical Success Factors for Twinning between midwives, a Delphi study.

    Science.gov (United States)

    Cadée, Franka; Nieuwenhuijze, Marianne J; Lagro-Janssen, Antoine L M; de Vries, Raymond

    2018-02-28

    To gain consensus for Critical Success Factors associated with Twinning in Midwifery. International publications identify midwifery as important for improving maternity care worldwide. Midwifery is a team effort where midwives play a key role. Yet their power to take on this role is often lacking. Twinning has garnered potential to develop power in professionals, however, its success varies because implementation is not always optimal. Critical Success Factors have demonstrated positive results in the managerial context and can be helpful to build effective Twinning relationships. We approached 56 midwife Twinning experts from 19 countries to participate in three Delphi rounds between 2016 - 2017. In round 1, experts gave input through an open ended questionnaire and this was analysed to formulate Critical Success Factors statements that were scored on a 1-7 Likert scale aiming to gain consensus in rounds 2 and 3. These statements were operationalized for practical use such as a check list in planning, monitoring and evaluation in the field. Thirty-three experts from 14 countries took part in all three Delphi rounds, producing 58 initial statements. This resulted in 25 Critical Success Factors covering issues of management, communication, commitment and values, most focus on equity. The Critical Success Factors formulated represent the necessary ingredients for successful Twinning by providing a practical implementation framework and promote further research into the effect of Twinning. Findings show that making equity explicit in Twinning may contribute towards the power of midwives to take on their identified key role. © 2018 The Authors. Journal of Advanced Nursing Published by John Wiley & Sons Ltd.

  3. First-principles studies on 3d transition metal atom adsorbed twin graphene

    Science.gov (United States)

    Li, Lele; Zhang, Hong; Cheng, Xinlu; Miyamoto, Yoshiyuki

    2018-05-01

    Twin graphene is a new two-dimensional semiconducting carbon allotrope which is proposed recently. The structural, magnetic and electronic properties are investigated for 3d transition metal (TM) atom adsorbed twin graphene by means of GGA+U calculations. The results show most of single 3d transition metal atom except Zn can make twin graphene magnetization. The adsorption of single TM atom can also make the twin graphene systems turn to half metal (V adsorption), half-semiconductor (Fe adsorption) or metal (Sc, Cr, Mn, Co and Cu adsorption). The semiconducting nature still exists for Ti, Ni and Zn adsorption. All the 3d TM adatoms belong to n-type doping for transferring charge to the neighboring C atoms and have strong covalent bond with these C atoms. The influence of Hubbard U value on half-metallic V adsorbed system is also considered. As the U increases, the system can gradually transform from metal to half metal and metal. The effect of the coverage is investigated for two TM atoms (Sc-Fe) adsorption, too. We can know TM atoms adsorbed twin graphene have potentials to be spintronic device and nanomagnets from the results.

  4. Traveling magnetospheric convection twin vortices: Another case study, global characteristics, and a model

    International Nuclear Information System (INIS)

    Glassmeier, K.H.; Heppner, C.

    1992-01-01

    A case study of a transient geomagnetic field variation event associated with a traveling magnetospheric convection twin vortex is presented. The characteristics of this event are different from those of other presented cases, as the sense of rotation of the associated ionospheric current system is reversed, that is, it exhibits upward (downward) field-aligned currents in the tailward (dayside) part of the vortex structure. In particular, a clear tailward motion at high latitudes can be deduced from local as well as global magnetic field observations. At low dayside latitudes, magnetic field variations similar to sudden impulse (SI) variations are recorded. Almost simultaneous onset and no westward propagation are observed, too. As possible source mechanisms of such transient events, localized magnetic field reconnection as well as pressure pulses at the dayside magnetopause are discussed. If the switch-on of magnetic reconnection can be regarded as equivalent to an equivalent current flowing against the existing magnetopause current and if this countercurrent is spatially localized, an Alfven wave is generated with downward (upward) field-aligned current flow in the tailward (dayside) par of the wave, as observed for some of the reported transients. However, the SI-like behavior of the event studied in this paper, its reversed sense of rotation, and the vortex associated field-aligned current density excludes such localized magnetic reconnection as a possible source mechanism and argues in favor of the existence of pressure pulses at the magnetopause

  5. Ferrobielastic twinning in irradiated quartz

    International Nuclear Information System (INIS)

    Shiau, S.M.

    1986-01-01

    Cultured quartz is usually free from electrical twinning; however, it may occur if the seed crystal is twinned or if undue applied forces are exerted on the crystal. Ferrobielastic twinning was studied optically (photoelastic effect) and electrically (piezoelectric effect). At room temperature, twins were perceptible at stresses of about 2.l5 x 10 8 N/m 2 , and crystals switched from their original states to the alternative twin states at stresses about 5.0 x 10 8 N/m 2 (called coercive stress). The decrease in coercive stress with increasing temperature was observed, and these coercive stresses become very low as temperatures reach to 300 0 C. The effects of irradiation on the twinning in quartz were also studied. The presence of defects produced by irradiation was utilized to pin the domain wall motion. Both neutrons and gamma rays were employed. The stress required to nucleate an appreciable volume of twins is about twice as high for irradiated crystals than for those unirradiated. This result demonstrated that the irradiated crystals can tolerate higher stresses. However, the coercive stress for complete switch-over was not much different for irradiated and unirradiated crystals. It appears that the defects caused by irradiation eliminate the initial twinning events but do not affect switch-over

  6. Roentgeno-cephalometric analysis on the twin

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hi Sup; Ahn, Hyung Kyu [College of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    1972-11-15

    The purpose of this investigation can be sought for studying varients between twin by the cephalometric roentgenog raphic technics. The author have applied Down's, Bjork and Sakamoto's technic and measured in various angulations and length of cephalometric points. The results are as follows; 1. No significantly different data were found between twin. 2. There was no differences between normality and twin.

  7. [A co-twin control study on birth weight, overweight and obesity among children younger than 18 years old in China].

    Science.gov (United States)

    Liu, Qingqing; Yu, Canqing; Gao, Wenjing; Cao, Weihua; Lyu, Jun; Wang, Shengfeng; Pang, Zengchang; Cong, Liming; Dong, Zhong; Wu, Fan; Wang, Hua; Wu, Xianping; Wang, Dezheng; Wang, Binyou; Li, Liming

    2016-04-01

    To analyze the associations between birth weight and overweight/obesity among children. A total of 8 267 twin pairs younger than 18 years old from the Chinese National Twin Registry were included in the study. Associations between birth weight, childhood BMI and overweight/obesity were explored by this co-twin control study. After adjusting for sex and zygosity, when birth weight had an increase of 0.5 kg per fold, the OR values for overweight and obesity were 1.87(95%CI: 1.40-2.48) for 2-6 year olds, 1.69 (95%CI: 1.16-2.46) for 6-12 year olds and 1.28 (95%CI: 0.80-2.07) for 12-18 year olds. from the stratified analysis in the 2-6 year-olds, statistically significant differences were seen. When birth weight increased 0.5 kg per fold, the risk of overweight and obesity increased by 0.87 times among the dizygotic twins, more than that of the monozygotic twins (OR=1.86, 95%CI:1.24-2.81). The risk for male twins was 1.12 times higher than that of female twins (OR=1.65, 95%CI:1.11-2.44). Birth weight seemed associated with overweight and obesity for kids at early childhood or at age for schools. However, guidance on the implementation of public health interventions is still needed on these children.

  8. Relativistic twins or sextuplets?

    International Nuclear Information System (INIS)

    Sheldon, Eric

    2003-01-01

    A recent study of the relativistic twin 'paradox' by Soni in this journal affirmed that 'A simple solution of the twin paradox also shows anomalous behaviour of rigidly connected distant clocks' but entailed a pedagogic hurdle which the present treatment aims to surmount. Two scenarios are presented: the first 'flight-plan' is akin to that depicted by Soni, with constant-velocity segments, while the second portrays an alternative mission undertaken with sustained acceleration and deceleration, illustrated quantitatively for a two-way spacecraft flight from Earth to Polaris (465.9 light years distant) and back

  9. Relativistic twins or sextuplets?

    CERN Document Server

    Sheldon, E S

    2003-01-01

    A recent study of the relativistic twin 'paradox' by Soni in this journal affirmed that 'A simple solution of the twin paradox also shows anomalous behaviour of rigidly connected distant clocks' but entailed a pedagogic hurdle which the present treatment aims to surmount. Two scenarios are presented: the first 'flight-plan' is akin to that depicted by Soni, with constant-velocity segments, while the second portrays an alternative mission undertaken with sustained acceleration and deceleration, illustrated quantitatively for a two-way spacecraft flight from Earth to Polaris (465.9 light years distant) and back.

  10. The Qingdao Twin Registry

    DEFF Research Database (Denmark)

    Duan, Haiping; Ning, Feng; Zhang, Dongfeng

    2013-01-01

    In 1998, the Qingdao Twin Registry was initiated as the main part of the Chinese National Twin Registry. By 2005, a total of 10,655 twin pairs had been recruited. Since then new twin cohorts have been sampled, with one longitudinal cohort of adolescent twins selected to explore determinants of me...

  11. Associations between social capital and depression: A study of adult twins.

    Science.gov (United States)

    Cohen-Cline, Hannah; Beresford, Shirley Aa; Barrington, Wendy; Matsueda, Ross; Wakefield, Jon; Duncan, Glen E

    2018-03-01

    Social capital is associated with depression independently of individual-level risk factors. We used a sample of 1586 same-sex twin pairs to test the association between seven measures of social capital and two related measures of neighborhood characteristics with depressive symptoms accounting for uncontrolled selection factors (i.e., genetics and shared environment). All measures of cognitive social capital and neighborhood characteristics were associated with less depressive symptoms in between-twin analysis. However, only measures of cognitive social capital were significantly associated with less depressive symptoms within-pairs. These results demonstrate that cognitive social capital is associated with depressive symptoms free of confounding from genetic and environmental factors shared within twins. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. A synthetic medical and sociological study of A-bomb exposed twin, 7

    International Nuclear Information System (INIS)

    Watanabe, Shoji; Satow, Yukio; Kyo, Taiichi

    1984-01-01

    The status of A-bomb exposure and family or relative relationship were investigated in seven twin pairs exposed to A-bomb (14 survivors). The survivors ranged in age between 4 and 24 years when they were exposed to A-bomb. Twins' relationship was comparatively strong. Both of the twins who were exposed to A-bomb tended to be closely connected with each other because of the fearful experience of A-bomb exposure and the subsequent hard social life. Even though one of the pair was not exposed to A-bomb, he (she) was likely to continue to help the other for a long time to restore from the disaster. (Namekawa, K.)

  13. Numerical study of internal flow in twin screw extruder and its mixing performance analysis

    International Nuclear Information System (INIS)

    Kim, Nak Soo; Kim, Hong Bum; Lee, Jae Wook

    2006-01-01

    We analyzed the non-Newtonian and non-isothermal flow in the melt conveying zone in co-rotating and counter-rotating screw extruder system with the commercial code, STAR-CD, and compared the mixing performance with respect to screw speed and rotating direction. The viscosity of fluid was described by power-law model. The dynamics of mixing was studied numerically by tracking the motion of particles in a twin screw extruder system. The extent of mixing was characterized in terms of the residence time distribution and average strain. The results showed that high screw speed decreases the residence time but increases the shear rate. Therefore higher screw speed increases the strain and has better mixing performance. Counter-rotating screw extruder system and co-rotating screw extruder has the similar shear rate with the same screw speed in spite of different rotating direction. However, the counter-rotating screw has good mixing performance, which is resulted from longer residence time than that of co-rotating screw extruder

  14. Behavioral and environmental modification of the genetic influence on body mass index: A twin study

    Science.gov (United States)

    Horn, Erin E.; Turkheimer, Eric; Strachan, Eric; Duncan, Glen E.

    2015-01-01

    Body mass index (BMI) has a strong genetic basis, with a heritability around 0.75, but is also influenced by numerous behavioral and environmental factors. Aspects of the built environment (e.g., environmental walkability) are hypothesized to influence obesity by directly affecting BMI, by facilitating or inhibiting behaviors such as physical activity that are related to BMI, or by suppressing genetic tendencies toward higher BMI. The present study investigated relative influences of physical activity and walkability on variance in BMI using 5,079 same-sex adult twin pairs (70% monozygotic, 65% female). High activity and walkability levels independently suppressed genetic variance in BMI. Estimating their effects simultaneously, however, suggested that the walkability effect was mediated by activity. The suppressive effect of activity on variance in BMI was present even with a tendency for low-BMI individuals to select into environments that require higher activity levels. Overall, our results point to community- or macro-level interventions that facilitate individual-level behaviors as a plausible approach to addressing the obesity epidemic among U.S. adults. PMID:25894925

  15. Retrospective reports of parental physical affection and parenting style: a study of Finnish twins.

    Science.gov (United States)

    Harlaar, Nicole; Santtila, Pekka; Björklund, Johanna; Alanko, Katarina; Jern, Patrick; Varjonen, Markus; von der Pahlen, Bettina; Sandnabba, Kenneth

    2008-08-01

    Individual differences in parenting behaviors are due, in part, to genetic factors. In the present study, the authors sought to determine whether the degree of genetic influence varied according to the type of parental behavior under consideration. A population-based sample of 2,334 pairs of Finnish twins provided ratings on the physical affection, control, abusiveness, and indifference shown by their father and mother during childhood. Genetic influences, shared environmental influences, and nonshared environmental influences accounted for a small-to-medium proportion (17%-30%), a small-to-large proportion (22%-44%), and a medium-to-large proportion (37%-55%) of the variance in each parenting measure, respectively. There were no significant differences in effect sizes for mothers and fathers or across the 4 types of parental behavior. The genetic results may reflect characteristic styles with which parents respond to genetically influenced behaviors of individuals (gene-environment correlations) or individual perceptions of this relationship (gene-person correlation processes). The findings have implications for intervention and prevention work with families and for interpretation of evidence for interactions between genes and parenting behaviors.

  16. Genetic and Environmental Structure of DSM-IV Criteria for Antisocial Personality Disorder: A Twin Study.

    Science.gov (United States)

    Rosenström, Tom; Ystrom, Eivind; Torvik, Fartein Ask; Czajkowski, Nikolai Olavi; Gillespie, Nathan A; Aggen, Steven H; Krueger, Robert F; Kendler, Kenneth S; Reichborn-Kjennerud, Ted

    2017-05-01

    Results from previous studies on DSM-IV and DSM-5 Antisocial Personality Disorder (ASPD) have suggested that the construct is etiologically multidimensional. To our knowledge, however, the structure of genetic and environmental influences in ASPD has not been examined using an appropriate range of biometric models and diagnostic interviews. The 7 ASPD criteria (section A) were assessed in a population-based sample of 2794 Norwegian twins by a structured interview for DSM-IV personality disorders. Exploratory analyses were conducted at the phenotypic level. Multivariate biometric models, including both independent and common pathways, were compared. A single phenotypic factor was found, and the best-fitting biometric model was a single-factor common pathway model, with common-factor heritability of 51% (95% CI 40-67%). In other words, both genetic and environmental correlations between the ASPD criteria could be accounted for by a single common latent variable. The findings support the validity of ASPD as a unidimensional diagnostic construct.

  17. Internalizing behavior in adolescent girls affects parental emotional overinvolvement: a cross-lagged twin study.

    Science.gov (United States)

    Moberg, Therese; Lichtenstein, Paul; Forsman, Mats; Larsson, Henrik

    2011-03-01

    The aim of this study was to examine the direction and the etiology of the association between different parenting styles (parental emotional overinvolvement [EOI] and parental criticism) and internalizing behavior from adolescence to early adulthood. A longitudinal genetically informative cross-lagged design was applied to a population-based sample of Swedish twins contacted at age 16-17 (n = 2369) and at age 19-20 (n = 1705). Sex-limitation modelling revealed different effects for boys and girls. For girls, genetic influences on internalizing problems at age 16-17 independently explained 2.7% of the heritability in parental EOI at age 19-20. These results suggest that emotionally overinvolved and self-sacrificing parental behavior stems in part from daughters (but not sons) genetic predisposition for internalizing behavior. These findings highlight the importance of genetically influenced child-driven effects underlying the parenting-internalizing association, and clarify that the role of such effects may differ depending on sex, type of parenting and developmental period.

  18. Is that me or my twin? Lack of self-face recognition advantage in identical twins.

    Directory of Open Access Journals (Sweden)

    Matteo Martini

    Full Text Available Despite the increasing interest in twin studies and the stunning amount of research on face recognition, the ability of adult identical twins to discriminate their own faces from those of their co-twins has been scarcely investigated. One's own face is the most distinctive feature of the bodily self, and people typically show a clear advantage in recognizing their own face even more than other very familiar identities. Given the very high level of resemblance of their faces, monozygotic twins represent a unique model for exploring self-face processing. Herein we examined the ability of monozygotic twins to distinguish their own face from the face of their co-twin and of a highly familiar individual. Results show that twins equally recognize their own face and their twin's face. This lack of self-face advantage was negatively predicted by how much they felt physically similar to their co-twin and by their anxious or avoidant attachment style. We speculate that in monozygotic twins, the visual representation of the self-face overlaps with that of the co-twin. Thus, to distinguish the self from the co-twin, monozygotic twins have to rely much more than control participants on the multisensory integration processes upon which the sense of bodily self is based. Moreover, in keeping with the notion that attachment style influences perception of self and significant others, we propose that the observed self/co-twin confusion may depend upon insecure attachment.

  19. In situ TEM study of deformation twinning in Ni-Mn-Ga non-modulated martensite

    Czech Academy of Sciences Publication Activity Database

    Zárubová, Niva; Ge, Y.; Heczko, Oleg; Hannula, S.-P.

    2013-01-01

    Roč. 61, č. 14 (2013), s. 5290-5299 ISSN 1359-6454 R&D Projects: GA ČR(CZ) GAP107/11/0391; GA MŠk(CZ) LM2011026; GA ČR GAP107/12/0800; GA AV ČR IAA100100920 Institutional support: RVO:68378271 Keywords : Ni-Mn-Ga * in situ TEM * magnetic shape memory * deformation twinning * twinning dislocation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.940, year: 2013

  20. Secular change in 13 metabolic phenotypes: A Chinese longitudinal twin study

    DEFF Research Database (Denmark)

    Li, Shuxia; Pang, Zengchang; Zhang, Dongfeng

    in prospective investigations. Based on Chinese twin data collected from Danish-Chinese collaboration research, we perform twin modeling on 13 metabolic phenotypes (total cholesterol; triglyceride; high density lipoprotein (HDL); low density lipoprotein (LDL); urine acid (UA); glucose; weight; body mass index...... fitted to the secular changes in each of the 13 phenotypes with best fitting model selected based on model performance. Age and sex were included as covariates in the models to adjust for their effects on secular trend. Results: Variations in secular change in 3 lipids (total cholesterol; triglyceride...

  1. Twin's Birth-Order Differences in Height and Body Mass Index From Birth to Old Age: A Pooled Study of 26 Twin Cohorts Participating in the CODATwins Project

    NARCIS (Netherlands)

    Yokoyama, Y.; Jelenkovic, A.; Sund, R.; Sung, J.; Hopper, J.L.; Ooki, S.; Heikkilä, K.; Aaltonen, S.; Tarnoki, A.D.; Tarnoki, D.L.; Willemsen, G.; Bartels, M.; van Beijsterveldt, C.E.M.; Saudino, K.J.; Cutler, T.L.; Nelson, T.L.; Whitfield, K.E.; Wardle, J.; Llewellyn, C.H.; Fisher, A.; He, M.; Ding, X.; Bjerregaard-Andersen, M.; Beck-Nielsen, H.; Sodemann, M.; Song, Y.M.; Yang, S.; Lee, K.; Jeong, H.U.; Knafo-Noam, A.; Mankuta, D.; Abramson, L.; Burt, S.A.; Klump, K.L.; Ordonana, J.R.; Sanchez-Romera, J.F.; Colodro-Conde, L.; Harris, J.R.; Brandt, I.; Sevenius Nilsen, T.; Craig, J.M.; Saffery, R.; Ji, F.; Ning, F.; Pang, Z.; Dubois, L.; Boivin, M.; Brendgen, M.; Dionne, G.; Vitaro, F.; Martin, N.G.; Medland, S.E.; Montgomery, G.W.; Magnusson, P.K.E.; Pedersen, N.L.; Dahl Aslan, A.K.; Tynelius, P.; Haworth, C.M.A.; Plomin, R.; Rebato, E.; Rose, R.J.; Goldberg, J.H.; Rasmussen, F.; Hur, Y.M.; Sørensen, T.I.A.; Boomsma, D.I.; Kaprio, J.; Silventoinen, K.

    2016-01-01

    We analyzed birth order differences in means and variances of height and body mass index (BMI) in monozygotic (MZ) and dizygotic (DZ) twins from infancy to old age. The data were derived from the international CODATwins database. The total number of height and BMI measures from 0.5 to 79.5 years of

  2. Genetic and environmental influences on adult attention deficit hyperactivity disorder symptoms: a large Swedish population-based study of twins.

    Science.gov (United States)

    Larsson, H; Asherson, P; Chang, Z; Ljung, T; Friedrichs, B; Larsson, J-O; Lichtenstein, P

    2013-01-01

    Attention deficit hyperactivity disorder (ADHD) frequently persists into adulthood. Family and twin studies delineate a disorder with strong genetic influences among children and adolescents based on parent- and teacher-reported data but little is known about the genetic and environmental contribution to DSM-IV ADHD symptoms in adulthood. We therefore aimed to investigate the impact of genetic and environmental influences on the inattentive and hyperactive-impulsive symptoms of ADHD in adults. Twin methods were applied to self-reported assessments of ADHD symptoms from a large population-based Swedish twin study that included data from 15 198 Swedish male and female twins aged 20 to 46 years. The broad heritability [i.e., A + D, where A is an additive genetic factor and D (dominance) a non-additive genetic factor] was 37% (A = 11%, D = 26%) for inattention and 38% (A = 18%, D = 20%) for hyperactivity-impulsivity. The results also indicate that 52% of the phenotypic correlation between inattention and hyperactivity-impulsivity (r = 0.43) was explained by genetic influences whereas the remaining part of the covariance was explained by non-shared environmental influences. These results were replicated across age strata. Our findings of moderate broad heritability estimates are consistent with previous literature on self-rated ADHD symptoms in older children, adolescents and adults and retrospective reports of self-rated childhood ADHD by adults but differ from studies of younger children with informant ratings. Future research needs to clarify whether our data indicate a true decrease in the heritability of ADHD in adults compared to children, or whether this relates to the use of self-ratings in contrast to informant data.

  3. Small effect of genetic factors on neck pain in old age: a study of 2,108 Danish twins 70 years of age and older

    DEFF Research Database (Denmark)

    Hartvigsen, Jan; Petersen, Hans Christian; Frederiksen, Henrik

    2005-01-01

    STUDY DESIGN: Classic twin study. OBJECTIVES: To determine the heritability of neck pain in persons 70 years of age and older. SUMMARY OF BACKGROUND DATA: Previous studies have shown a moderate effect of genetic factors on back pain in the elderly. Genetic influence on neck pain in old age...... calculated and compared for monozygotic and dizygotic twins. Further, heritability estimates were calculated using bivariate probit estimation. RESULTS: A total of 2,108 twin individuals, including 1,054 complete twin pairs, answered the question related to neck pain at intake into the Longitudinal Study...... environmental risk factors (rheumatoid arthritis, osteoarthritis, disc prolapse, and coronary heart disease) showed no significant additive genetic, dominant genetic, or common environmental effects. CONCLUSION: Genetic factors do not play an important role in the liability to neck pain in persons 70 years...

  4. Adolescent Victimization and Early-Adult Psychopathology: Approaching Causal Inference Using a Longitudinal Twin Study to Rule Out Noncausal Explanations

    Science.gov (United States)

    Schaefer, Jonathan D.; Moffitt, Terrie E.; Arseneault, Louise; Danese, Andrea; Fisher, Helen L.; Houts, Renate; Sheridan, Margaret A.; Wertz, Jasmin; Caspi, Avshalom

    2017-01-01

    Adolescence is the peak age for both victimization and mental disorder onset. Previous research has reported associations between victimization exposure and many psychiatric conditions. However, causality remains controversial. Within the Environmental Risk Longitudinal Twin Study, we tested whether seven types of adolescent victimization increased risk of multiple psychiatric conditions and approached causal inference by systematically ruling out noncausal explanations. Longitudinal within-individual analyses showed that victimization was followed by increased mental health problems over a childhood baseline of emotional/behavioral problems. Discordant-twin analyses showed that victimization increased risk of mental health problems independent of family background and genetic risk. Both childhood and adolescent victimization made unique contributions to risk. Victimization predicted heightened generalized liability (the “p factor”) to multiple psychiatric spectra, including internalizing, externalizing, and thought disorders. Results recommend violence reduction and identification and treatment of adolescent victims to reduce psychiatric burden. PMID:29805917

  5. Variance components models for physical activity with age as modifier: a comparative twin study in seven countries

    DEFF Research Database (Denmark)

    Vink, Jacqueline M; Boomsma, Dorret I; Medland, Sarah E

    2011-01-01

    -reported data from twins aged 19 to 50 from seven countries that collaborated in the GenomEUtwin project: Australia, Denmark, Finland, Norway, Netherlands, Sweden and United Kingdom. Results confirmed the importance of genetic influences on physical activity in all countries and showed an age-related decrease......Physical activity is influenced by genetic factors whose expression may change with age. We employed an extension to the classical twin model that allows a modifier variable, age, to interact with the effects of the latent genetic and environmental factors. The model was applied to self...... into account when exploring the genetic and environmental contribution to physical activity. It also suggests that the power of genome-wide association studies to identify the genetic variants contributing to physical activity may be larger in young adult cohorts....

  6. Kangaroo care and behavioral and physiologic pain responses in very-low-birth-weight twins: a case study.

    Science.gov (United States)

    Cong, Xiaomei; Cusson, Regina M; Hussain, Naveed; Zhang, Di; Kelly, Sharon P

    2012-09-01

    The purpose of this case study was to describe pain responses in three study conditions: longer (30 minutes) kangaroo care (KC) before and throughout heel stick (KC30), shorter (15 minutes) KC before and throughout heel stick (KC15), and incubator care throughout heel stick (IC) in 28-week gestational age twins. Pain responses were measured by crying time, Preterm Infant Pain Profile (PIPP), and heart rate variability indexes, including low-frequency power (LF, representing sympathetic activity), high-frequency power (HF, parasympathetic activity), and LF/HF ratio (sympathetic-parasympathetic balance). Both twins cried more and had higher PIPP pain scores and tachycardia during heel stick in the IC condition. Infant B had an incident of apnea and tachycardia by the end of the heel stick and a bradycardia episode during recovery in the IC condition. The twins had lower LF/HF ratios (better autonomic nervous system balance) during recovery in both longer and shorter KC conditions compared with the IC condition. Infant B had difficulty returning to LF/HF ratio baseline level after the painful procedure in the IC condition. These data suggest that both longer and shorter KC before and throughout painful procedures can be helpful in reducing behavioral and physiologic pain responses in preterm infants. Copyright © 2012 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

  7. Experiences of young smokers in quitting smoking in twin cities of Pakistan: a phenomenological study.

    Science.gov (United States)

    Shaheen, Kanwal; Oyebode, Oyinlola; Masud, Haleema

    2018-04-10

    Smoking is highly prevalent in Pakistan claiming the lives of over 100,000 individuals every year. A significant proportion of smokers (24.7%) make an attempt to quit each year but 97.4% fail to quit successfully. Little is known about the reasons for, and experiences of, failed quit attempts. This study was carried out to explore the experiences of young male smokers in quitting smoking in the twin cities of Pakistan METHOD: A qualitative study was carried out using a phenomenological approach in Rawalpindi and Islamabad. A total of 11 participants were interviewed. All study participants were male and had made at least one quit attempt. Study participants were a mix of smokers who failed to quit smoking, intermittent smokers and successful quitters. Streubert's (1991) method of phenomenology was followed during data analysis. The experiences of smokers while smoking "the smoking phase" have major effects on their journey towards quitting smoking. The smoking phase consists of three major stages: contact with initial smoking stimuli, the journey from first puff to enjoying smoking and then finally smoking becoming part of life. However, the journey towards quitting smoking is not as simple as the journey towards becoming a smoker. Instead, smokers get trapped in three overlapping cycles of smoking and quit attempts: smoking & forced quitting, smoking & intentional quitting, and smoking & intermittent smoking before successful quitting. Breaking the cycle is not easy in the presence of trapping factors (addiction, high availability, easy affordability, conducive social setup and low perceived risks of smoking). Three factors play a major role in breaking these cycles which are strong will power, continuous peer support and avoidance of smokers' company. A young smoker, during his experience of quitting smoking gets entrapped in several overlapping cycles of smoking & quit attempts before successful quitting. There are known entrapping factors as well as factors

  8. Epidemiological and birth weight characteristics of triplets: a study from the Dutch twin register

    NARCIS (Netherlands)

    Orlebeke, J.F.; Boomsma, D.I.; Eriksson, A.W.

    1993-01-01

    From 112 triplet sets, born in The Netherlands from the end of 1986 to the beginning of 1991 and registered in the Dutch Twin Register, several details such as birth weight, gestational age, zygosity, and etiology were assessed by questionnaire, which was filled out by the mother. For 33 triplet

  9. Shared Genetics of Temporomandibular Disorder Pain and Neck Pain : Results of a Twin Study

    NARCIS (Netherlands)

    Visscher, Corine M; Schouten, Maarten J; Ligthart, Lannie; van Houtem, Caroline Mhh; de Jongh, Ad; Boomsma, Dorret I

    2018-01-01

    AIMS: (1) To examine the heritability of TMD pain and of neck pain; and (2) to estimate the potential overlap in genetic and environmental factors influencing TMD pain and neck pain. METHODS: Data from 2,238 adult female twins who completed a survey on TMD pain and neck pain were analyzed. The total

  10. Application of hierarchical genetic models to Raven and WAIS subtests: a Dutch twin study

    NARCIS (Netherlands)

    Rijsdijk, F.V.; Vernon, P.A.; Boomsma, D.I.

    2002-01-01

    Hierarchical models of intelligence are highly informative and widely accepted. Application of these models to twin data, however, is sparse. This paper addresses the question of how a genetic hierarchical model fits the Wechsler Adult Intelligence Scale (WAIS) subtests and the Raven Standard

  11. Genetic and Environmental Parent-Child Transmission of Value Orientations: An Extended Twin Family Study

    Science.gov (United States)

    Kandler, Christian; Gottschling, Juliana; Spinath, Frank M.

    2016-01-01

    Despite cross-cultural universality of core human values, individuals differ substantially in value priorities, whereas family members show similar priorities to some degree. The latter has often been attributed to intrafamilial socialization. The analysis of self-ratings on eight core values from 399 twin pairs (ages 7-11) and their biological…

  12. Individual differences in P300 amplitude: a genetic study in adolescent twins

    NARCIS (Netherlands)

    van Beijsterveldt, C.E.M.; Molenaar, P.C.M.; de Geus, E.J.C.; Boomsma, D.I.

    1998-01-01

    Using quantitative genetic research designs, we decomposed phenotypic variance in P300 parameters into genetic and environmental components. The twin method was used to carry out this decomposition. Event related potentials (ERPs) were measured during a visual oddball paradigm in a sample of 213

  13. Individual differences in P300 amplitude: A genetic study in adolescent twins.

    NARCIS (Netherlands)

    van Beijsterveld, C.E.M.; Molenaar, P.C.M.; de Geus, E.J.C.; Boomsma, D.I.

    1998-01-01

    Using quantitative genetic research designs, we decomposed phenotypic variance in P300 parameters into genetic and environmental components. The twin method was used to carry out this decomposition. Event related potentials (ERPs) were measured during a visual oddball paradigm in a sample of 213

  14. Genetic and environmental influences on motor function: a magnetoencephalographic study of twins

    Directory of Open Access Journals (Sweden)

    Toshihiko eAraki

    2014-06-01

    Full Text Available To investigate the effect of genetic and environmental influences on cerebral motor function, we determined similarities of movement-related cortical fields (MRCFs in middle-aged and elderly monozygotic (MZ twins. MRCFs were measured using a 160-channel MEG system when MZ twins were instructed to repeat lifting of the right index finger. We compared latency, amplitude, dipole location, and dipole intensity of movement-evoked field 1 (MEF1 between 16 MZ twins and 16 pairs of genetically unrelated pairs. Differences in latency and dipole location between MZ twins were significantly less than those between unrelated age-matched pairs. However, amplitude and dipole intensity were not significantly different. These results suggest that the latency and dipole location of MEF1 are determined early in life by genetic and early common environmental factors, whereas amplitude and dipole intensity are influenced by long-term environmental factors. Improved understanding of genetic and environmental factors that influence cerebral motor function may contribute to evaluation and improvement for individual motor function.

  15. Medical and sociological study on the A-bombed twins, 3

    International Nuclear Information System (INIS)

    Satow, Yukio; Okamoto, Naomasa; Watanabe, Shoji; Ohkita, Takeshi; Kurihara, Minoru

    1980-01-01

    Three A-bomb exposed and nonexposed pairs of monoxygotic twins were investigated. In two pairs of them, environmental factors had no apparent influence, and genetic factors were dominant. In the other one pair, one of which was a A-bomb survivor exposed at 1.5 km from the explosion center, environmental factors and various effects on them. (Ueda, J.)

  16. The Screening India′s Twin Epidemic: Study design and methodology (SITE-1

    Directory of Open Access Journals (Sweden)

    Shashank R Joshi

    2011-01-01

    Full Text Available Objectives: The recent years have seen a surge in the prevalence of both diabetes and hypertension. Significant demographic variations reported on the prevalence patterns of diabetes and hypertension in India establish a clear need for a nation-wide surveillance study. The Screening India′s Twin Epidemic (SITE study aimed at collecting information on the prevalence of diagnosed and undiagnosed diabetes and hypertension cases in outpatient settings in major Indian states to better understand disease management, as well as to estimate the extent of underlying risk factors. Materials and Methods: During 2009-2010, SITE was conducted in eight states, in waves - one state at a time. It was planned to recruit about 2000 patients from 100 centers per wave. Each center enrolled the first 10 eligible patients (≥18 years of age, not pregnant, signed data release consent form, and ready to undergo screening tests per day on two consecutive days. Patient demographics, medical history, and laboratory investigation results were collected and statistically interpreted. The protocol defined diabetes and hypertension as per the American Diabetes Association (ADA and Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7 recommendations, respectively. Results: After the first two pilot phases in Maharashtra and Delhi, the protocol was refined and the laboratory investigations were simplified to be further employed for all other states, namely, Tamil Nadu, West Bengal, Karnataka, Andhra Pradesh, Madhya Pradesh, and Gujarat. Conclusion: SITE′s nation-wide approach will provide a real-world perspective on diabetes and hypertension and its contributing risk factors. Results from the study will raise awareness on the need for early diagnosis and management of these diseases to reduce complications.

  17. Increased frequency of micronuclei in adults with a history of childhood sexual abuse: a discordant monozygotic twin study.

    Directory of Open Access Journals (Sweden)

    Timothy P York

    Full Text Available Childhood sexual abuse (CSA is a traumatic life event associated with an increased lifetime risk for psychopathology/morbidity. The long-term biological consequences of CSA-elicited stress on chromosomal stability in adults are unknown. The primary aim of this study was to determine if the rate of acquired chromosomal changes, measured using the cytokinesis-block micronucleus assay on stimulated peripheral blood lymphocytes, differs in adult female monozygotic twins discordant for CSA.Monozygotic twin pairs discordant for CSA were identified from a larger population-based sample of female adult twins for whom the experience of CSA was assessed by self-report (51 individuals including a reference sample. Micronuclei (MN contain chromatin from structurally normal or abnormal chromosomes that are excluded from the daughter nuclei during cell division and serve as a biomarker to assess acquired chromosomal instability.Female twins exposed to CSA exhibited a 1.63-fold average increase in their frequency of MN compared to their nonexposed genetically identical cotwins (Paired t-test, t₁₆ = 2.65, P = 0.017. No additional effects of familial factors were detected after controlling for the effect of CSA exposure. A significant interaction between CSA history and age was observed, suggesting that the biological effects of CSA on MN formation may be cumulative.These data support a direct link between CSA exposure and MN formation measured in adults that is not attributable to genetic or environmental factors shared by siblings. Further research is warranted to understand the biological basis for the observed increase in acquired chromosomal findings in people exposed to CSA and to determine if acquired somatic chromosomal abnormalities/somatic clonal mosaicism might mediate the adult pathology associated with CSA.

  18. Rationale, Design, and Methodological Aspects of the BUDAPEST-GLOBAL Study (Burden of Atherosclerotic Plaques Study in Twins-Genetic Loci and the Burden of Atherosclerotic Lesions).

    Science.gov (United States)

    Maurovich-Horvat, Pál; Tárnoki, Dávid L; Tárnoki, Ádám D; Horváth, Tamás; Jermendy, Ádám L; Kolossváry, Márton; Szilveszter, Bálint; Voros, Viktor; Kovács, Attila; Molnár, Andrea Á; Littvay, Levente; Lamb, Hildo J; Voros, Szilard; Jermendy, György; Merkely, Béla

    2015-12-01

    The heritability of coronary atherosclerotic plaque burden, coronary geometry, and phenotypes associated with increased cardiometabolic risk are largely unknown. The primary aim of the Burden of Atherosclerotic Plaques Study in Twins-Genetic Loci and the Burden of Atherosclerotic Lesions (BUDAPEST-GLOBAL) study is to evaluate the influence of genetic and environmental factors on the burden of coronary artery disease. By design this is a prospective, single-center, classical twin study. In total, 202 twins (61 monozygotic pairs, 40 dizygotic same-sex pairs) were enrolled from the Hungarian Twin Registry database. All twins underwent non-contrast-enhanced computed tomography (CT) for the detection and quantification of coronary artery calcium and for the measurement of epicardial fat volumes. In addition, a single non-contrast-enhanced image slice was acquired at the level of L3-L4 to assess abdominal fat distribution. Coronary CT angiography was used for the detection and quantification of plaque, stenosis, and overall coronary artery disease burden. For the primary analysis, we will assess the presence and volume of atherosclerotic plaques. Furthermore, the 3-dimensional coronary geometry will be assessed based on the coronary CT angiography datasets. Additional phenotypic analyses will include per-patient epicardial and abdominal fat quantity measurements. Measurements obtained from monozygotic and dizygotic twin pairs will be compared to evaluate the genetic or environmental effects of the given phenotype. The BUDAPEST-GLOBAL study provides a unique framework to shed some light on the genetic and environmental influences of cardiometabolic disorders. © 2015 Wiley Periodicals, Inc.

  19. Skewed X inactivation and survival: a 13-year follow-up study of elderly twins and singletons

    DEFF Research Database (Denmark)

    Mengel-From, Jonas; Thinggaard, Mikael; Christiansen, Lene

    2012-01-01

    In mammalian females, one of the two X chromosomes is inactivated in early embryonic life. Females are therefore mosaics for two cell populations, one with the maternal and one with the paternal X as the active X chromosome. A skewed X inactivation is a marked deviation from a 50:50 ratio...... mortality than the majority of women who had a more skewed DS (hazard ratio: 1.30; 95% CI: 1.04-1.64). The association between X inactivation and mortality was replicated in dizygotic twin pairs for which the co-twin with the lowest DS also had a statistically significant tendency to die first in the twin....... In populations of women past 55-60 years of age, an increased degree of skewing (DS) is found. Here the association between age-related skewing and mortality is analyzed in a 13-year follow-up study of 500 women from three cohorts (73-100 years of age at intake). Women with low DS had significantly higher...

  20. Biotin-dependent functions in adiposity: a study of monozygotic twin pairs.

    Science.gov (United States)

    Järvinen, E; Ismail, K; Muniandy, M; Bogl, L H; Heinonen, S; Tummers, M; Miettinen, S; Kaprio, J; Rissanen, A; Ollikainen, M; Pietiläinen, K H

    2016-05-01

    Biotin acts as a coenzyme for carboxylases regulating lipid and amino-acid metabolism. We investigated alterations of the biotin-dependent functions in obesity and the downstream effects of biotin restriction in adipocytes in vitro. Twenty-four monozygotic twin pairs discordant for body mass index (BMI). Mean within-pair difference (heavy-lean co-twin, Δ) of BMI was 6.0 kg m(-2) (range 3.1-15.2 kg m(-)(2)). Adipose tissue (AT) DNA methylation, gene expression of AT and adipocytes, and leukocytes (real-time quantitative PCR), serum biotin, C-reactive protein (CRP) and triglycerides were measured in the twins. Human adipocytes were cultured in low and control biotin concentrations and analyzed for lipid droplet content, mitochondrial morphology and mitochondrial respiration. The gene expression levels of carboxylases, PCCB and MCCC1, were upregulated in the heavier co-twins' leukocytes. ΔPCCB (r=0.91, P=0.0046) and ΔMCCC1 (r=0.79, P=0.036) correlated with ΔCRP within-pairs. Serum biotin levels were lower in the heavier (274 ng l(-1)) than in the lean co-twins (390 ng l(-1), P=0.034). ΔBiotin correlated negatively with Δtriglycerides (r=-0.56, P=0.045) within-pairs. In AT, HLCS and ACACB were hypermethylated and biotin cycle genes HLCS and BTD were downregulated (PBiotin-dependent carboxylases were downregulated (ACACA, ACACB, PCCB, MCCC2 and PC; Pbiotin had decreased lipid accumulation, altered mitochondrial morphology and deficient mitochondrial respiration. Biotin-dependent functions are modified by adiposity independent of genetic effects, and correlate with inflammation and hypertriglyceridemia. Biotin restriction decreases lipid accumulation and respiration, and alters mitochondrial morphology in adipocytes.

  1. A population-based twin study of self-esteem and gender.

    Science.gov (United States)

    Kendler, K S; Gardner, C O; Prescott, C A

    1998-11-01

    Self-esteem (SE), a widely used construct in the social sciences, is usually conceptualized as a reflection of socialization and interpersonal experiences that may differ considerably between the genders. The Rosenberg self-esteem scale was assessed at personal interview in both members of 3793 unselected twin pairs (1517 male-male, 856 female-female and 1420 male-female) from the population-based Virginia Twin Registry. Gender effects on SE were assessed by both analysis of variance and biometrical twin modelling. The mean SE score was slightly but significantly lower in women v. men, and in women who grew up with a male v. a female co-twin. Twin modelling suggested that: (i) individual differences in self-esteem in both men and women were best explained by genetic and individual-specific environment factors; (ii) heritability estimates were similar in women (32%) and in men (29%); and (iii) the same genetic factors that influenced SE in women also influenced SE in men. Analyses supported the validity of the equal environment assumption for SE. The heritability of SE cannot be explained by the moderate correlation between SE and symptoms of depression. These results are inconsistent with prominent gender-related aetiological models for SE, which postulate that individual differences arise from socialization experiences both within and outside the home of origin which differ widely for the two genders. Instead, a significant proportion of the population variance in SE is due to genetically-influenced temperamental variables that are the same in men and women.

  2. Aortic root dimensions are predominantly determined by genetic factors: a classical twin study

    Energy Technology Data Exchange (ETDEWEB)

    Celeng, Csilla; Kolossvary, Marton; Kovacs, Attila; Molnar, Andrea Agnes; Szilveszter, Balint; Karolyi, Mihaly; Jermendy, Adam L.; Karady, Julia; Merkely, Bela; Maurovich-Horvat, Pal [Semmelweis University, MTA-SE Cardiovascular Imaging Research Group, Heart and Vascular Center, Budapest (Hungary); Horvath, Tamas [Budapest University of Technology and Economics, Department of Hydrodynamic Systems, Budapest (Hungary); Tarnoki, Adam D.; Tarnoki, David L. [Semmelweis University, Department of Radiology and Oncotherapy, Budapest (Hungary); Voros, Szilard [Global Genomics Group, Atlanta, GA (United States); Jermendy, Gyoergy [Bajcsy-Zsilinszky Hospital, Medical Department, Budapest (Hungary)

    2017-06-15

    Previous studies using transthoracic echocardiography (TTE) observed moderate heritability of aortic root dimensions. Computed tomography angiography (CTA) might provide more accurate heritability estimates. Our primary aim was to assess the heritability of the aortic root with CTA. Our secondary aim was to derive TTE-based heritability and compare this with the CTA-based results. In the BUDAPEST-GLOBAL study 198 twin subjects (118 monozygotic, 80 dizygotic; age 56.1 ± 9.4 years; 126 female) underwent CTA and TTE. We assessed the diameter of the left ventricular outflow tract (LVOT), annulus, sinus of Valsalva, sinotubular junction and ascending aorta. Heritability was assessed using ACDE model (A additive genetic, C common environmental, D dominant genetic, E unique environmental factors). Based on CTA, additive genetic effects were dominant (LVOT: A = 0.67, E = 0.33; annulus: A = 0.76, E = 0.24; sinus of Valsalva: A = 0.83, E = 0.17; sinotubular junction: A = 0.82, E = 0.18; ascending aorta: A = 0.75, E = 0.25). TTE-derived measurements showed moderate to no genetic influence (LVOT: A = 0.38, E = 0.62; annulus: C = 0.47, E = 0.53; sinus of Valsalva: C = 0.63, E = 0.37; sinotubular junction: C = 0.45, E = 0.55; ascending aorta: A = 0.67, E = 0.33). CTA-based assessment suggests that aortic root dimensions are predominantly determined by genetic factors. TTE-based measurements showed moderate to no genetic influence. The choice of measurement method has substantial impact on heritability estimates. (orig.)

  3. Aortic root dimensions are predominantly determined by genetic factors: a classical twin study

    International Nuclear Information System (INIS)

    Celeng, Csilla; Kolossvary, Marton; Kovacs, Attila; Molnar, Andrea Agnes; Szilveszter, Balint; Karolyi, Mihaly; Jermendy, Adam L.; Karady, Julia; Merkely, Bela; Maurovich-Horvat, Pal; Horvath, Tamas; Tarnoki, Adam D.; Tarnoki, David L.; Voros, Szilard; Jermendy, Gyoergy

    2017-01-01

    Previous studies using transthoracic echocardiography (TTE) observed moderate heritability of aortic root dimensions. Computed tomography angiography (CTA) might provide more accurate heritability estimates. Our primary aim was to assess the heritability of the aortic root with CTA. Our secondary aim was to derive TTE-based heritability and compare this with the CTA-based results. In the BUDAPEST-GLOBAL study 198 twin subjects (118 monozygotic, 80 dizygotic; age 56.1 ± 9.4 years; 126 female) underwent CTA and TTE. We assessed the diameter of the left ventricular outflow tract (LVOT), annulus, sinus of Valsalva, sinotubular junction and ascending aorta. Heritability was assessed using ACDE model (A additive genetic, C common environmental, D dominant genetic, E unique environmental factors). Based on CTA, additive genetic effects were dominant (LVOT: A = 0.67, E = 0.33; annulus: A = 0.76, E = 0.24; sinus of Valsalva: A = 0.83, E = 0.17; sinotubular junction: A = 0.82, E = 0.18; ascending aorta: A = 0.75, E = 0.25). TTE-derived measurements showed moderate to no genetic influence (LVOT: A = 0.38, E = 0.62; annulus: C = 0.47, E = 0.53; sinus of Valsalva: C = 0.63, E = 0.37; sinotubular junction: C = 0.45, E = 0.55; ascending aorta: A = 0.67, E = 0.33). CTA-based assessment suggests that aortic root dimensions are predominantly determined by genetic factors. TTE-based measurements showed moderate to no genetic influence. The choice of measurement method has substantial impact on heritability estimates. (orig.)

  4. Tobacco use and reported bruxism in young adults: A nationwide Finnish Twin Cohort Study

    Science.gov (United States)

    Ahlberg, J.; Hublin, C.; Lobbezoo, F.; Rose, R. J.; Murtomaa, H.; Kaprio, J.

    2010-01-01

    Introduction: Higher levels of smoking, leading to increased levels of nicotine and dopamine release, may be more strongly related to bruxism, although this relationship has remained unclear. Thus, the aim of the present study was to investigate the possible effect of cumulative tobacco use on bruxism in a large sample of young adults. Methods: The material of the present study derives from the FinnTwin16, which consists of five birth cohorts born in 1975–1979. A total of 3,124 subjects (mean age 24 years, range 23–27 years) provided data in 2000–2002 on frequency of bruxism and tobacco use. Multinomial logistic regression was used to explore the relationships of frequency of bruxism with smoking and smokeless tobacco use while controlling covariates (alcohol intoxication, alcohol problems [Rutgers Alcohol Problem Index, RAPI], illicit drug use, psychological distress [General Health Questionnaire], and coffee use). Results: Based on subjective response and multivariate analyses, weekly bruxers were more than two times more likely to report heavy smoking than never bruxers (odds ratio [OR] 2.5, 95 % CI 1.8–3.4). The significant association between heavy smoking and bruxism held when the effects of other tobacco use and multiple covariates were controlled. In addition, the use of smokeless tobacco emerged as an independent risk factor for bruxism. Discussion: Given the observed associations with both heavy smoking and smokeless tobacco and a dose–response relationship, the present results support our hypothesis of a link between nicotine intake and bruxism. PMID:20427458

  5. Heritability of brain activity related to response inhibition: a longitudinal genetic study in adolescent twins

    Science.gov (United States)

    Anokhin, Andrey P.; Golosheykin, Simon; Grant, Julia D.; Heath, Andrew C.

    2017-01-01

    The ability to inhibit prepotent but context- or goal-inappropriate responses is essential for adaptive self-regulation of behavior. Deficits in response inhibition, a key component of impulsivity, have been implicated as a core dysfunction in a range of neuropsychiatric disorders such as ADHD and addictions. Identification of genetically transmitted variation in the neural underpinnings of response inhibition can help to elucidate etiological pathways to these disorders and establish the links between genes, brain, and behavior. However, little is known about genetic influences on the neural mechanisms of response inhibition during adolescence, a developmental period characterized by weak self-regulation of behavior. Here we investigated heritability of ERPs elicited in a Go/No-Go task in a large sample of adolescent twins assessed longitudinally at ages 12, 14, and 16. Genetic analyses showed significant heritability of inhibition-related frontal N2 and P3 components at all three ages, with 50 to 60% of inter-individual variability being attributable to genetic factors. These genetic influences included both common genetic factors active at different ages and novel genetic influences emerging during development. Finally, individual differences in the rate of developmental changes from age 12 to age 16 were significantly influenced by genetic factors. In conclusion, the present study provides the first evidence for genetic influences on neural correlates of response inhibition during adolescence and suggests that ERPs elicited in the Go/No-Go task can serve as intermediate neurophysiological phenotypes (endophenotypes) for the study of disinhibition and impulse control disorders. PMID:28300615

  6. Using Twins to Better Understand Sibling Relationships.

    Science.gov (United States)

    Mark, Katharine M; Pike, Alison; Latham, Rachel M; Oliver, Bonamy R

    2017-03-01

    We compared the nature of the sibling relationship in dyads of varying genetic relatedness, employing a behavioural genetic design to estimate the contribution that genes and the environment have on this familial bond. Two samples were used-the Sisters and Brothers Study consisted of 173 families with two target non-twin children (mean ages = 7.42 and 5.22 years respectively); and the Twins, Family and Behaviour study included 234 families with two target twin children (mean age = 4.70 years). Mothers and fathers reported on their children's relationship with each other, via a postal questionnaire (the Sisters and Brothers Study) or a telephone interview (the Twins, Family and Behaviour study). Contrary to expectations, no mean level differences emerged when monozygotic twin pairs, dizygotic twin pairs, and non-twin pairs were compared on their sibling relationship quality. Behavioural genetic analyses also revealed that the sibling bond was modestly to moderately influenced by the genetic propensities of the children within the dyad, and moderately to substantially influenced by the shared environment common to both siblings. In addition, for sibling negativity, we found evidence of twin-specific environmental influence-dizygotic twins showed more reciprocity than did non-twins. Our findings have repercussions for the broader application of results from future twin-based investigations.

  7. Establishing a Twin Registry in Guinea-Bissau

    DEFF Research Database (Denmark)

    Bjerregaard-Andersen, Morten; Gomes, Margarida A; Joaquím, Luis C

    2013-01-01

    represent a powerful tool. Though twin studies have been carried out by the Bandim Health Project for more than 30 years, the renewed registry described here was officially established in 2009 and includes both a cohort of newborn twins and a cohort of young and adult twins. Currently more than 1,500 twins...

  8. Longitudinal associations between social anxiety disorder and avoidant personality disorder: A twin study.

    Science.gov (United States)

    Torvik, Fartein Ask; Welander-Vatn, Audun; Ystrom, Eivind; Knudsen, Gun Peggy; Czajkowski, Nikolai; Kendler, Kenneth S; Reichborn-Kjennerud, Ted

    2016-01-01

    Social anxiety disorder (SAD) and avoidant personality disorder (AvPD) are frequently co-occurring psychiatric disorders with symptomatology related to fear of social situations. It is uncertain to what degree the 2 disorders reflect the same genetic and environmental risk factors. The current study addresses the stability and co-occurrence of SAD and AvPD, the factor structure of the diagnostic criteria, and genetic and environmental factors underlying the disorders at 2 time points. SAD and AvPD were assessed in 1,761 young adult female twins at baseline and 1,471 of these approximately 10 years later. Biometric models were fitted to dimensional representations of SAD and AvPD. SAD and AvPD were moderately and approximately equally stable from young to middle adulthood, with increasing co-occurrence driven by environmental factors. At the first wave, approximately 1 in 3 individuals with AvPD had SAD, increasing to 1 in 2 at follow-up. The diagnostic criteria for SAD and AvPD had a two-factor structure with low cross-loadings. The relationship between SAD and AvPD was best accounted for by a model with separate, although highly correlated (r = .76), and highly heritable (.66 and .71) risk factors for each disorder. Their genetic and environmental components correlated .84 and .59, respectively. The finding of partially distinct risk factors indicates qualitative differences in the etiology of SAD and AvPD. Genetic factors represented the strongest time-invariant influences, whereas environmental factors were most important at the specific points in time. (c) 2016 APA, all rights reserved.

  9. Adiponectin Levels and Longitudinal Changes in Metabolic Syndrome: The Healthy Twin Study.

    Science.gov (United States)

    Song, Yun-Mi; Lee, Kayoung; Sung, Joohon

    2015-09-01

    We investigated the association of plasma adiponectin levels with longitudinal changes in metabolic syndrome and the metabolic syndrome-related traits [insulin and homeostasis model assessment of insulin resistance (HOMA-IR)], as well as their genetic and environmental correlations. A total of 1030 Koreans (380 men and 650 women; 44.0 ± 12.7 years old) without diabetes of the Healthy Twin Study visited at baseline (2005-2010) and returned for a follow-up examination 3.7 ± 1.2 years later. Baseline plasma adiponectin, metabolic syndrome components [waist circumference (WC), glucose, blood pressure, high-density lipoprotein cholesterol (HDL-C), and triglycerides (TGs)] and metabolic syndrome-related traits were measured at baseline and follow-up. After adjusting for age, sex, smoking, alcohol consumption, physical activity, caloric intake, education level, body mass index (BMI), family history of diabetes, and changes in BMI, 1 standard deviation increment in baseline adiponectin levels was associated with 38-63% lower odds of incident and persistent metabolic syndrome. After additionally adjusting for the baseline levels of each trait, baseline adiponectin levels were inversely associated with WC, blood pressure, insulin, HOMA-IR, and TGs values at follow-up. After adjusting for age, sex, and baseline values of each trait or sum of metabolic syndrome components, baseline adiponectin levels exhibited significantly inverse genetic and environmental correlations with insulin, HOMA-IR, and HDL-C values and the sum of metabolic syndrome components at follow-up. High adiponectin levels reduce the risk of developing metabolic syndrome and having persistent metabolic syndrome and increase of metabolic syndrome-related traits over time. These associations may be explained by pleiotropic genetic mechanisms.

  10. Absence of the spleen(s) in conjoined twins: a diagnostic clue of laterality defects? Radiological study of historical specimens

    NARCIS (Netherlands)

    Oostra, R. J.; Keulen, N.; Jansen, T.; van Rijn, R. R.

    2012-01-01

    Laterality defects are quite common in thoracoileopagus and parapagus dicephalus but rare in other types of conjoined twins. To present the presumed laterality defects in cephalothoracoileopagus and prosopothoracoileopagus conjoined twins, based on the unilateral or bilateral absence or duplication

  11. Register-based research on twins

    DEFF Research Database (Denmark)

    Christensen, Kaare; Ohm Kyvik, Kirsten; Holm, Niels V

    2011-01-01

    Introduction: The Danish Twin Registry (DTR) has for more than 50 years been based on surveys and clinical investigations and over the two last decades also on register linkage. Currently these two approaches are merged within Statistics Denmark. Research topics: Here we report on three major...... groups of register-based research in the DTR that used the uniqueness of twinning. First, we focus on the ''long-term prognosis'' of being a twin compared with being a singleton and show that Danish twins have health trajectories in adulthood similar to singletons, which is a result of interest for twins...... illustrate how the co-twin control method in a register setting can be used to control for the effect of rearing environment and genetic factors in studies of the association between exposures and health. CONCLUSION: The spectrum of register-based twin studies is very wide and have changed in accordance...

  12. Evaluation of twin-head electrospray nanoparticle disperser for nanotoxicity study

    Science.gov (United States)

    Liu, Qiaoling; Budiman, Thomas; Chen, Da-Ren

    2014-08-01

    With the rapid development of nanotechnology, nanoparticles with various sizes and compositions have been synthesized and proposed for industrial applications. At the same time, the health effects and environmental impacts of nanoparticles become an emerging concern to be addressed. Both in vitro and in vivo studies are of importance to better understand the toxicity of nanoparticles. It is thus essential to have a nanoparticle disperser capable of dispersing individual nanoparticles for these studies. A twin-head electrospray (THES) nanoparticle disperser for animal inhalation exposure studies has recently become commercially available from TSE Systems Inc. Different from the cone-jet electrospray method used in the majority of literature, this particular disperser operates at the multi-jet mode. In this study, we reported our finding on the performance evaluation of the THES disperser with respect to its mass throughput and quality of size distribution of aerosol produced. Three different nanomaterials (TiO2, ZnO, and NiO) were used in this study. It is found that the maximal mass throughput of the studied disperser was achieved by keeping the distance between two opposite spray capillary tips at 3.0 cm, operating the primary carrier-to-capillary sheath flow rates at the ratio of 4:3, and feeding spray suspensions at a flow rate of 20 µl/min. Under the above settings and operations, the highest mass concentration for nano-ZnO was measured at 14.56 mg/m3. Nanoparticle streams with higher concentrations can be further produced by lowering the total carrier gas flow rate and spraying suspensions of higher nanomaterial concentrations. Our study also found that the particle mass throughput of the studied disperser had a good linear relationship with the mass concentration of spray suspension. In addition, the spatial uniformity of nano aerosol distribution in a TSE head-nose-only exposure chamber was investigated. An acceptable nano aerosol uniformity result was

  13. Genetic influences on alcohol use behaviors have diverging developmental trajectories: a prospective study among male and female twins.

    Science.gov (United States)

    Meyers, Jacquelyn L; Salvatore, Jessica E; Vuoksimaa, Eero; Korhonen, Tellervo; Pulkkinen, Lea; Rose, Richard J; Kaprio, Jaakko; Dick, Danielle M

    2014-11-01

    Both alcohol-specific genetic factors and genetic factors related to externalizing behavior influence problematic alcohol use. Little is known, however, about the etiologic role of these 2 components of genetic risk on alcohol-related behaviors across development. Prior studies conducted in a male cohort of twins suggest that externalizing genetic factors are important for predicting heavy alcohol use in adolescence, whereas alcohol-specific genetic factors increase in importance during the transition to adulthood. In this report, we studied twin brothers and sisters and brother-sister twin pairs to examine such developmental trajectories and investigate whether sex and cotwin sex effects modify these genetic influences. We used prospective, longitudinal twin data collected between ages 12 and 22 within the population-based FinnTwin12 cohort study (analytic n = 1,864). Our dependent measures of alcohol use behaviors included alcohol initiation (age 12), intoxication frequency (ages 14 and 17), and alcohol dependence criteria (age 22). Each individual's genetic risk of alcohol use disorders (AUD-GR) was indexed by his/her parents' and cotwin's DSM-IV Alcohol Dependence (AD) criterion counts. Likewise, each individual's genetic risk of externalizing disorders (EXT-GR) was indexed with a composite measure of parents' and cotwin's DSM-IV Conduct Disorder and Antisocial Personality Disorder criterion counts. EXT-GR was most strongly related to alcohol use behaviors during adolescence, while AUD-GR was most strongly related to alcohol problems in young adulthood. Further, sex of the twin and sex of the cotwin significantly moderated the associations between genetic risk and alcohol use behaviors across development: AUD-GR influenced early adolescent alcohol use behaviors in females more than in males, and EXT-GR influenced age 22 AD more in males than in females. In addition, the associations of AUD-GR and EXT-GR with intoxication frequency were greater among 14- and

  14. Genetic and Environmental Contributions to Behavioral Stability and Change in Children 6-36 months of Age Using Louisville Twin Study Data.

    Science.gov (United States)

    Davis, Deborah Winders; Finkel, Deborah; Turkheimer, Eric; Dickens, William

    2015-11-01

    The Infant Behavior Record (IBR) from the Bayley Scales of Infant Development has been used to study behavioral development since the 1960s. Matheny (1983) examined behavioral development at 6, 12, 18, and 24 months from the Louisville Twin Study (LTS). The extracted temperament scales included Task Orientation, Affect-Extraversion, and Activity. He concluded that monozygotic twins were more similar than same-sex dizygotic twins on these dimensions. Since this seminal work was published, a larger LTS sample and more advanced analytical methods are available. In the current analyses, Choleksy decomposition was applied to behavioral data (n = 1231) from twins 6-36 months. Different patterns of genetic continuity vs genetic innovations were identified for each IBR scale. Single common genetic and shared environmental factors explained cross-age twin similarity in the Activity scale. Multiple shared environmental factors and a single genetic factor coming on line at age 18 months contributed to Affect-Extraversion. A single shared environmental factor and multiple genetic factors explained cross-age twin similarity in Task Orientation.

  15. Long-term relationships between symptoms of Attention Deficit Hyperactivity Disorder and self-esteem in a prospective longitudinal study of twins.

    Science.gov (United States)

    Edbom, Tobias; Lichtenstein, Paul; Granlund, Mats; Larsson, Jan-Olov

    2006-06-01

    To study the long-term relationship between symptoms of Attention Deficit Hyperactivity Disorder and the developing self-esteem in a population-based sample of twins. The cohort is all twin pair families born in Sweden between May 1985 and December 1986 (n = 1.480). Wave 1 took place in 1994 when the twins were 8 years old and wave 2 in 1999 when the children were 13 years old. In wave 1 and 2 the parents completed questionnaires regarding ADHD-symptoms about their children. In wave 2 the twins completed a questionnaire about self-esteem and Youth Self Report (YSR). ADHD-symptoms and self-esteem were analyzed in the total study group. There was a long-term relationship between high scores of parental-reported ADHD-symptoms at 8 and 13 years of age and low scores in measures of self-reported self-esteem at 13 years of age. In the cotwin control method controlling for YSR internalizing problem, paired comparisons within the twin pairs revealed that a high score of ADHD-symptoms at age 8 was related to significantly lower scores at age 13 in the self-esteem. The long-term relationships between ADHD-symptoms and a low self-esteem in a population-based sample were confirmed by the co-twin analyses.

  16. Twin Higgs Asymmetric Dark Matter.

    Science.gov (United States)

    García García, Isabel; Lasenby, Robert; March-Russell, John

    2015-09-18

    We study asymmetric dark matter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20  GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful dark matter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors.

  17. Birth order of twins and risk of perinatal death related to delivery in England, Northern Ireland, and Wales, 1994-2003: retrospective cohort study

    Science.gov (United States)

    Fleming, Kate M; White, Ian R

    2007-01-01

    Objective To determine the effect of birth order on the risk of perinatal death in twin pregnancies. Design Retrospective cohort study. Setting England, Northern Ireland, and Wales, 1994-2003. Participants 1377 twin pregnancies with one intrapartum stillbirth or neonatal death from causes other than congenital abnormality and one surviving infant. Main outcome measures The risk of perinatal death in the first and second twin estimated with conditional logistic regression. Results There was no association between birth order and the risk of death overall (odds ratio 1.0, 95% confidence interval 0.9 to 1.1). However, there was a highly significant interaction with gestational age (P<0.001). There was no association between birth order and the risk of death among infants born before 36 weeks' gestation but there was an increased risk of death among second twins born at term (2.3, 1.7 to 3.2, P<0.001), which was stronger for deaths caused by intrapartum anoxia or trauma (3.4, 2.2 to 5.3). Among term births, there was a trend (P=0.1) towards a greater risk of the second twin dying from anoxia among those delivered vaginally (4.1, 1.8 to 9.5) compared with those delivered by caesarean section (1.8, 0.9 to 3.6). Conclusions In this cohort, compared with first twins, second twins born at term were at increased risk of perinatal death related to delivery. Vaginally delivered second twins had a fourfold risk of death caused by intrapartum anoxia. PMID:17337456

  18. Twinned crystals of adeno-associated virus serotype 3b prove suitable for structural studies

    International Nuclear Information System (INIS)

    Lerch, Thomas F.; Xie, Qing; Ongley, Heather M.; Hare, Joan; Chapman, Michael S.

    2009-01-01

    Crystals of adeno-associated virus serotype 3b, a human DNA virus with promise as a vector for gene therapy, have been grown, diffract X-rays to ∼2.6 Å resolution and are suitable for structure determination in spite of twinning. Adeno-associated viruses (AAVs) are leading candidate vectors for gene-therapy applications. The AAV-3b capsid is closely related to the well characterized AAV-2 capsid (87% identity), but sequence and presumably structural differences lead to distinct cell-entry and immune-recognition properties. In an effort to understand these differences and to perhaps harness them, diffraction-quality crystals of purified infectious AAV-3b particles have been grown and several partial diffraction data sets have been recorded. The crystals displayed varying levels of merohedral twinning that in earlier times would have rendered them unsuitable for structure determination, but here is shown to be a tractable complication

  19. Family environment, not heredity, accounts for family resemblances in food preferences and attitudes: a twin study.

    Science.gov (United States)

    Rozin, P; Millman, L

    1987-04-01

    Monozygotic and same-sex dizygotic twin pairs reported on their food preferences, the variety of foods of the same general category (e.g. types of soup) in their diet, and their concern about contact of their food with disgusting or other unacceptable substances (contamination sensitivity). Although there was substantial resemblance between siblings for many of these items, there was no clear evidence for a heritable component on any item. The only case for which there was an interpretable and significantly greater resemblance among monozygotic than among dizygotic twins (out of 23 questions) was preferred degree of hotness resulting from chili pepper in foods. These results confirm the prediction that in omnivorous animals, such as humans, genetic predispositions will be minimal with respect to food. The modest sibling resemblances on a number of measures are primarily attributable to a shared environment.

  20. The genetic and environmental foundations of political, psychological, social, and economic behaviors: a panel study of twins and families.

    Science.gov (United States)

    Hatemi, Peter K; Smith, Kevin; Alford, John R; Martin, Nicholas G; Hibbing, John R

    2015-06-01

    Here we introduce the Genetic and Environmental Foundations of Political and Economic Behaviors: A Panel Study of Twins and Families (PIs Alford, Hatemi, Hibbing, Martin, and Smith). This study was designed to explore the genetic and environmental influences on social, economic, and political behaviors and attitudes. It involves identifying the psychological mechanisms that operate on these traits, the heritability of complex economic and political traits under varying conditions, and specific genetic correlates of attitudes and behaviors. In addition to describing the study, we conduct novel analyses on the data, estimating the heritability of two traits so far unexplored in the extant literature: Machiavellianism and Baron-Cohen's Empathizing Quotient.

  1. A longitudinal twin study on IQ, executive functioning, and attention problems during childhood and early adolescence.

    Science.gov (United States)

    Polderman, Tinca J C; Gosso, M Florencia; Posthuma, Danielle; Van Beijsterveldt, Toos C E M; Heutink, Peter; Verhulst, Frank C; Boomsma, Dorret I

    2006-12-01

    Variation in human behavior may be caused by differences in genotype and by non-genetic differences ("environment") between individuals. The relative contributions of genotype (G) and environment (E) to phenotypic variation can be assessed with the classical twin design. We illustrate this approach with longitudinal data collected in 5 and 12-year-old Dutch twins. At age 5 data on cognitive abilities as assessed with a standard intelligence test (IQ), working memory, selective and sustained attention, and attention problems were collected in 237 twin pairs. Seven years later, 172 twin pairs participated again when they were 12 years old and underwent a similar protocol. Results showed that variation in all phenotypes was influenced by genetic factors. For IQ the heritability estimates increased from 30% at age 5, to 80% at age 12. For executive functioning performance genetic factors accounted for around 50% of the variance at both ages. Attention problems showed high heritabilities (above 60%) at both ages, for maternal and teacher ratings. Longitudinal analyses revealed that executive functioning during childhood was weakly correlated with IQ scores at age 12. Attention problems during childhood, as rated by the mother and the teacher were stronger predictors (r = -0.28 and -0.36, respectively). This association could be attributed to a partly overlapping set of genes influencing attention problems at age 5 and IQ at age 12. IQ performance at age 5 was the best predictor of IQ at age 12. IQ at both ages was influenced by the same genes, whose influence was amplified during development.

  2. Creating a social world: a developmental twin study of peer-group deviance.

    Science.gov (United States)

    Kendler, Kenneth S; Jacobson, Kristen C; Gardner, Charles O; Gillespie, Nathan; Aggen, Steven A; Prescott, Carol A

    2007-08-01

    Peer-group deviance is strongly associated with externalizing behaviors. We have limited knowledge of the sources of individual differences in peer-group deviance. To clarify genetic and environmental contributions to peer-group deviance in twins from midchildhood through early adulthood. Retrospective assessments using a life-history calendar. Analysis by biometric growth curves. General community. Members of male-male pairs from the population-based Virginia Twin Registry personally interviewed in 1998-2004 (n = 1802). Self-reported peer-group deviance at ages 8 to 11, 12 to 14, 15 to 17, 18 to 21, and 22 to 25 years. Mean and variance of peer-group deviance increased substantially with age. Genetic effects on peer-group deviance showed a strong and steady increase over time. Family environment generally declined in importance over time. Individual-specific environmental influences on peer-group deviance levels were stable in the first 3 age periods and then increased as most twins left home. When standardized, the heritability of peer-group deviance is approximately 30% at ages 8 to 11 years and rises to approximately 50% across the last 3 time periods. Both genes and shared environment contributed to individual differences in the developmental trajectory of peer-group deviance. However, while the correlation between childhood peer-group deviance levels and the subsequent slope of peer-group deviance over time resulting from genetic factors was positive, the same relationship resulting from shared environmental factors was negative. As male twins mature and create their own social worlds, genetic factors play an increasingly important role in their choice of peers, while shared environment becomes less influential. The individual-specific environment increases in importance when individuals leave home. Individuals who have deviant peers in childhood, as a result of genetic vs shared environmental influences, have distinct developmental trajectories

  3. Ontogenetic de novo copy number variations (CNVs as a source of genetic individuality: studies on two families with MZD twins for schizophrenia.

    Directory of Open Access Journals (Sweden)

    Sujit Maiti

    2011-03-01

    Full Text Available Genetic individuality is the foundation of personalized medicine, yet its determinants are currently poorly understood. One issue is the difference between monozygotic twins that are assumed identical and have been extensively used in genetic studies for decades. Here, we report genome-wide alterations in two nuclear families each with a pair of monozygotic twins discordant for schizophrenia evaluated by the Affymetrix 6.0 human SNP array. The data analysis includes characterization of copy number variations (CNVs and single nucleotide polymorphism (SNPs. The results have identified genomic differences between twin pairs and a set of new provisional schizophrenia genes. Samples were found to have between 35 and 65 CNVs per individual. The majority of CNVs (~80% represented gains. In addition, ~10% of the CNVs were de novo (not present in parents, of these, 30% arose during parental meiosis and 70% arose during developmental mitosis. We also observed SNPs in the twins that were absent from both parents. These constituted 0.12% of all SNPs seen in the twins. In 65% of cases these SNPs arose during meiosis compared to 35% during mitosis. The developmental mitotic origin of most CNVs that may lead to MZ twin discordance may also cause tissue differences within individuals during a single pregnancy and generate a high frequency of mosaics in the population. The results argue for enduring genome-wide changes during cellular transmission, often ignored in most genetic analyses.

  4. Comparative Study on Educational Management in Public and Private Institutions in the Twin Cities of Pakistan

    Directory of Open Access Journals (Sweden)

    Rizwan Muhammad

    2016-12-01

    Full Text Available The aim of this research paper is to compare the quality of education delivered at the undergraduate level in the public and private institutions of the Twin Cities (Islamabad and Rawalpindi in Pakistan. Data is collected with the help of questionnaires from 246 students. The data was collected from three public and three private educational institutions of the Twin Cities, and the age of students ranged from 18 to 27 years. The research instrument used in this paper is the independent sample t-test to find the difference between the three private and three public educational institutions selected in Rawalpindi and Islamabad in terms of different variables that are very important in measuring the quality of education. For analysis, Levene’s test was adopted, which reflects the variations in educational quality with respect to academic staff availability in the twin cities. The differences in close supervision of students by academic staff between public and private sector educational institutions were also analysed, and the results reflected a difference between private and public educational institutions with respect to close supervision of students. The results also highlighted the factors that are involved in higher performance of students in private institutes as compared to that of students in public institutes. These factors can be implemented in the public sector to increase student performance.

  5. Importance of genetic factors in the etiology of atopic dermatitis: a twin study

    DEFF Research Database (Denmark)

    Thomsen, Simon F; Ulrik, Charlotte S; Kyvik, Kirsten O

    2007-01-01

    The susceptibility to develop atopic dermatitis can be attributed both to genetic and environmental causes. We estimated the relative impact of genetic and environmental factors in the etiology of atopic dermatitis in a population-based sample of twins. From the birth cohorts of 1953-1982 who wer...... dermatitis both in male and female patients (p = 0.98). The estimates were adjusted for age. The susceptibility to develop atopic dermatitis is attributable to mainly genetic differences between people. However, differences in environmental exposures also are of importance......The susceptibility to develop atopic dermatitis can be attributed both to genetic and environmental causes. We estimated the relative impact of genetic and environmental factors in the etiology of atopic dermatitis in a population-based sample of twins. From the birth cohorts of 1953-1982 who were...... with a threefold increased risk among cotwins of an affected fraternal twin, relative to the general population. Genes accounted for 82% and nonshared environmental factors accounted for 18% of the individual susceptibility to develop atopic dermatitis. The same genes contributed to the susceptibility to atopic...

  6. Modeling acardiac twin pregnancies

    NARCIS (Netherlands)

    de Groot, Rosa; van den Wijngaard, Jeroen P. H. M.; Umur, Asli; Beek, Johan F.; Nikkels, Peter G. J.; van Gemert, Martin J. C.

    2007-01-01

    Acardiac twin pregnancies are a rare but severe complication of monochorionic twinning, where the acardiac twin lacks cardiac function but nevertheless grows during pregnancy because it is perfused by the pump twin through a set of placental arterioarterial and venovenous anastomoses. Because the

  7. Molecular dynamics simulation of deformation twin in rocksalt vanadium nitride

    International Nuclear Information System (INIS)

    Fu, Tao; Peng, Xianghe; Zhao, Yinbo; Li, Tengfei; Li, Qibin; Wang, Zhongchang

    2016-01-01

    We perform molecular dynamics simulation of nano-indentation with a cylindrical indenter to investigate the formation mechanism of deformation twin in vanadium nitride (VN) with a rocksalt structure. We find that the deformation twins occur during the loading stage, and subsequently conduct a systematic analysis of nucleation, propagation and thickening of a deformation twin. We find that the nucleation of a partial dislocation and its propagation to form a stacking fault are premise of deformation twin formation. The sequential nucleation and propagation of partial dislocation on adjacent parallel {111} planes are found to cause the thickening of the deformation twin. Moreover, the deformation twins can exist in VN at room temperature. - Highlights: • MD simulations of indentation are performed to study the deformation twin in VN. • The deformation twins can occur in VN during the loading stage. • The nucleation, propagation and thickening of a deformation twin are analyzed. • The deformation twins can exist in VN at room temperature.

  8. Not all risks are created equal: A twin study and meta-analyses of risk taking across seven domains.

    Science.gov (United States)

    Wang, X T Xiao-Tian; Zheng, Rui; Xuan, Yan-Hua; Chen, Jie; Li, Shu

    2016-11-01

    Humans routinely deal with both traditional and novel risks. Different kinds of risks have been a driving force for both evolutionary adaptations and personal development. This study explored the genetic and environmental influences on human risk taking in different task domains. Our approach was threefold. First, we integrated several scales of domain-specific risk-taking propensity and developed a synthetic scale, including both evolutionarily typical and modern risks in the following 7 domains: cooperation/competition, safety, reproduction, natural/physical risk, moral risk, financial risk, and gambling. Second, we conducted a twin study using the scale to estimate the contributions of genes and environment to risk taking in each of these 7 domains. Third, we conducted a series of meta-analyses of extant twin studies across the 7 risk domains. The results showed that individual differences in risk-taking propensity and its consistency across domains were mainly regulated by additive genetic influences and individually unique environmental experiences. The heritability estimates from the meta-analyses ranged from 29% in financial risk taking to 55% in safety. Supporting the notion of risk-domain specificity, both the behavioral and genetic correlations among the 7 domains were generally low. Among the relatively few correlations between pairs of risk domains, our analysis revealed a common genetic factor that regulates moral, financial, and natural/physical risk taking. This is the first effort to separate genetic and environmental influences on risk taking across multiple domains in a single study and integrate the findings of extant twin studies via a series of meta-analyses conducted in different task domains. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  9. Different neural processes accompany self-recognition in photographs across the lifespan: an ERP study using dizygotic twins.

    Science.gov (United States)

    Butler, David L; Mattingley, Jason B; Cunnington, Ross; Suddendorf, Thomas

    2013-01-01

    Our appearance changes over time, yet we can recognize ourselves in photographs from across the lifespan. Researchers have extensively studied self-recognition in photographs and have proposed that specific neural correlates are involved, but few studies have examined self-recognition using images from different periods of life. Here we compared ERP responses to photographs of participants when they were 5-15, 16-25, and 26-45 years old. We found marked differences between the responses to photographs from these time periods in terms of the neural markers generally assumed to reflect (i) the configural processing of faces (i.e., the N170), (ii) the matching of the currently perceived face to a representation already stored in memory (i.e., the P250), and (iii) the retrieval of information about the person being recognized (i.e., the N400). There was no uniform neural signature of visual self-recognition. To test whether there was anything specific to self-recognition in these brain responses, we also asked participants to identify photographs of their dizygotic twins taken from the same time periods. Critically, this allowed us to minimize the confounding effects of exposure, for it is likely that participants have been similarly exposed to each other's faces over the lifespan. The same pattern of neural response emerged with only one exception: the neural marker reflecting the retrieval of mnemonic information (N400) differed across the lifespan for self but not for twin. These results, as well as our novel approach using twins and photographs from across the lifespan, have wide-ranging consequences for the study of self-recognition and the nature of our personal identity through time.

  10. Different neural processes accompany self-recognition in photographs across the lifespan: an ERP study using dizygotic twins.

    Directory of Open Access Journals (Sweden)

    David L Butler

    Full Text Available Our appearance changes over time, yet we can recognize ourselves in photographs from across the lifespan. Researchers have extensively studied self-recognition in photographs and have proposed that specific neural correlates are involved, but few studies have examined self-recognition using images from different periods of life. Here we compared ERP responses to photographs of participants when they were 5-15, 16-25, and 26-45 years old. We found marked differences between the responses to photographs from these time periods in terms of the neural markers generally assumed to reflect (i the configural processing of faces (i.e., the N170, (ii the matching of the currently perceived face to a representation already stored in memory (i.e., the P250, and (iii the retrieval of information about the person being recognized (i.e., the N400. There was no uniform neural signature of visual self-recognition. To test whether there was anything specific to self-recognition in these brain responses, we also asked participants to identify photographs of their dizygotic twins taken from the same time periods. Critically, this allowed us to minimize the confounding effects of exposure, for it is likely that participants have been similarly exposed to each other's faces over the lifespan. The same pattern of neural response emerged with only one exception: the neural marker reflecting the retrieval of mnemonic information (N400 differed across the lifespan for self but not for twin. These results, as well as our novel approach using twins and photographs from across the lifespan, have wide-ranging consequences for the study of self-recognition and the nature of our personal identity through time.

  11. Trapping of oxygen vacancies on twin walls of CaTiO3: a computer simulation study

    International Nuclear Information System (INIS)

    Calleja, Mark; Dove, Martin T; Salje, Ekhard K H

    2003-01-01

    We have studied the atomic structure of [001] 90 deg. rotation twin walls in orthorhombic CaTiO 3 (symmetry Pbnm) at low temperature (10 K) and their effects on oxygen vacancies. The wall thickness was found to be 2.3 nm at T || T c and it was found that it is energetically favourable for such vacancies to reside in the wall, particularly when bridging titania ions in the (001) plane. The binding energy of an oxygen vacancy in the wall with respect to the bulk is calculated to be ≤ 1.2 eV

  12. Genetic and environmental etiology of stability and changes in self-esteem linked to personality: A Japanese twin study

    OpenAIRE

    Shikishima, Chizuru; Hiraishi, Kai; Takahashi, Yusuke; Yamagata, Shinji; Yamaguchi, Susumu; Ando, Juko

    2018-01-01

    This study used a behavioral genetic approach to examine the genetic and environmental etiology of stability and changes in self-esteem in relation to personality. Multiple genetic analyses were conducted on a longitudinal dataset of self-esteem and Big Five personality scores among young adult Japanese twins over the course of a decade. There were 1221 individuals for whom data were available on both self-esteem and the Big Five personality test at Time 1 and 365 at Time 2. The mean interval...

  13. Progesterone for the prevention of preterm birth in twin pregnancy (STOPPIT): a randomised, double-blind, placebo-controlled study and meta-analysis.

    Science.gov (United States)

    Norman, Jane E; Mackenzie, Fiona; Owen, Philip; Mactier, Helen; Hanretty, Kevin; Cooper, Sarah; Calder, Andrew; Mires, Gary; Danielian, Peter; Sturgiss, Stephen; MacLennan, Graeme; Tydeman, Graham; Thornton, Steven; Martin, Bill; Thornton, James G; Neilson, James P; Norrie, John

    2009-06-13

    Women with twin pregnancy are at high risk for spontaneous preterm delivery. Progesterone seems to be effective in reducing preterm birth in selected high-risk singleton pregnancies, albeit with no significant reduction in perinatal mortality and little evidence of neonatal benefit. We investigated the use of progesterone for prevention of preterm birth in twin pregnancy. In this double-blind, placebo-controlled trial, 500 women with twin pregnancy were recruited from nine UK National Health Service clinics specialising in the management of twin pregnancy. Women were randomised, by permuted blocks of randomly mixed sizes, either to daily vaginal progesterone gel 90 mg (n=250) or to placebo gel (n=250) for 10 weeks from 24 weeks' gestation. All study personnel and participants were masked to treatment assignment for the duration of the study. The primary outcome was delivery or intrauterine death before 34 weeks' gestation. Analysis was by intention to treat. Additionally we undertook a meta-analysis of published and unpublished data to establish the efficacy of progesterone in prevention of early (<34 weeks' gestation) preterm birth or intrauterine death in women with twin pregnancy. This study is registered, number ISRCTN35782581. Three participants in each group were lost to follow-up, leaving 247 analysed per group. The combined proportion of intrauterine death or delivery before 34 weeks of pregnancy was 24.7% (61/247) in the progesterone group and 19.4% (48/247) in the placebo group (odds ratio [OR] 1.36, 95% CI 0.89-2.09; p=0.16). The rate of adverse events did not differ between the two groups. The meta-analysis confirmed that progesterone does not prevent early preterm birth in women with twin pregnancy (pooled OR 1.16, 95% CI 0.89-1.51). Progesterone, administered vaginally, does not prevent preterm birth in women with twin pregnancy. Chief Scientist Office of the Scottish Government Health Directorate.

  14. Neighborhood walkability moderates the association between low back pain and physical activity: A co-twin control study.

    Science.gov (United States)

    Zadro, J R; Shirley, D; Pinheiro, M B; Bauman, A; Duncan, G E; Ferreira, P H

    2017-06-01

    The aim of this study was to investigate whether neighborhood walkability moderates the association between low back pain (LBP) and physical activity (PA), using a co-twin design to control for genetics and shared environmental factors. A cross-sectional analysis was performed on 10,228 twins from the Washington State Twin Registry with available data on LBP from recruitment surveys between 2009 and 2013. LBP within the past 3months was our exposure variable. Our outcome variables were sufficient moderate or vigorous-intensity PA (MVPA, defined as at least 75min of vigorous-intensity PA, or 150min of moderate-intensity PA per week), and walking (≥150min per week). Neighborhood walkability, estimated using the commercially available Walk Score®, was our moderator variable. After controlling for the influence of genetics and shared environment, individuals reporting LBP were significantly less likely to engage in sufficient MVPA if they lived in a neighborhood with high walkability (OR=0.59, 95%CI: 0.36-0.96). There was no association between LBP and sufficient MVPA for individuals living in a neighborhood with low walkability (OR=1.27, 95%CI: 0.93-1.72), demonstrating that walkability is a significant moderator of the association between LBP and PA (interaction p=0.013). These findings were similar for the association between LBP and walking (high walkability OR=0.42, 95%CI: 0.22-0.78; low walkability OR=0.71, 95%CI: 0.46-1.12), although the interaction was not significant (p=0.700). Neighborhood walkability moderates the association between LBP and PA. Our results highlight the importance of targeting interventions promoting PA towards individuals with LBP living in a neighborhood with good walkable access to amenities. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Genetic and environmental influences on non-specific neck pain in early adolescence: A classical twin study

    Science.gov (United States)

    Ståhl, Minna K; El-Metwally, Ashraf A; Mikkelsson, Marja K; Salminen, Jouko J; Pulkkinen, Lea R; Rose, Richard J; Kaprio, Jaakko A

    2012-01-01

    Background Prevalence of neck pain has increased among adolescents. The origins of adult chronic neck pain may lie in late childhood, but for early prevention, more information is needed about its aetiology. We investigated the relative roles of genetic and environmental factors in early adolescent neck pain with a classic twin study. Methods Frequency of neck pain was assessed with a validated pain questionnaire in a population-based sample of nearly 1800 pairs of 11–12-year-old Finnish twins. Twin pair similarity for neck pain was quantified by polychoric correlations, and variance components were estimated with biometric structural equation modelling. Results Prevalence of neck pain reported at least once monthly was 38% and at least once weekly 16%, with no significant differences between gender or zygosity. A greater polychoric correlation in liability to neck pain was found in monozygotic (0.67) than for dizygotic pairs (0.38), suggesting strong genetic influences. Model-fitting indicated that 68% (95% CI 62 to 74) of the variation in liability to neck pain could be attributed to genetic effects, with the remainder attributed to unshared environmental effects. No evidence for sex-specific genetic effects or for sex differences in the magnitude of genetic effects was found. Conclusions Genetic and unique environmental factors seem to play the most important roles in liability to neck pain in early adolescence. Future research should be directed to identifying pathways for genetic influences on neck pain and in exploring effectiveness of interventions that target already identified environmental risk factors. PMID:23139100

  16. Establishing the resting state default mode network derived from functional magnetic resonance imaging tasks as an endophenotype: A twins study.

    Science.gov (United States)

    Korgaonkar, Mayuresh S; Ram, Kaushik; Williams, Leanne M; Gatt, Justine M; Grieve, Stuart M

    2014-08-01

    The resting state default mode network (DMN) has been shown to characterize a number of neurological and psychiatric disorders. Evidence suggests an underlying genetic basis for this network and hence could serve as potential endophenotype for these disorders. Heritability is a defining criterion for endophenotypes. The DMN is measured either using a resting-state functional magnetic resonance imaging (fMRI) scan or by extracting resting state activity from task-based fMRI. The current study is the first to evaluate heritability of this task-derived resting activity. 250 healthy adult twins (79 monozygotic and 46 dizygotic same sex twin pairs) completed five cognitive and emotion processing fMRI tasks. Resting state DMN functional connectivity was derived from these five fMRI tasks. We validated this approach by comparing connectivity estimates from task-derived resting activity for all five fMRI tasks, with those obtained using a dedicated task-free resting state scan in an independent cohort of 27 healthy individuals. Structural equation modeling using the classic twin design was used to estimate the genetic and environmental contributions to variance for the resting-state DMN functional connectivity. About 9-41% of the variance in functional connectivity between the DMN nodes was attributed to genetic contribution with the greatest heritability found for functional connectivity between the posterior cingulate and right inferior parietal nodes (P<0.001). Our data provide new evidence that functional connectivity measures from the intrinsic DMN derived from task-based fMRI datasets are under genetic control and have the potential to serve as endophenotypes for genetically predisposed psychiatric and neurological disorders. Copyright © 2014 Wiley Periodicals, Inc.

  17. Temperament and character in the Child and Adolescent Twin Study in Sweden (CATSS: comparison to the general population, and genetic structure analysis.

    Directory of Open Access Journals (Sweden)

    Danilo Garcia

    Full Text Available BACKGROUND: The Child and Adolescent Twin Study in Sweden (CATSS is an on-going, large population-based longitudinal twin study. We aimed (1 to investigate the reliability of two different versions (125-items and 238-items of Cloninger's Temperament and Character Inventory (TCI used in the CATSS and the validity of extracting the short version from the long version, (2 to compare these personality dimensions between twins and adolescents from the general population, and (3 to investigate the genetic structure of Cloninger's model. METHOD: Reliability and correlation analyses were conducted for both TCI versions, 2,714 CATSS-twins were compared to 631 adolescents from the general population, and the genetic structure was investigated through univariate genetic analyses, using a model-fitting approach with structural equation-modeling techniques based on same-sex twin pairs from the CATSS (423 monozygotic and 408 dizygotic pairs. RESULTS: The TCI scores from the short and long versions showed comparable reliability coefficients and were strongly correlated. Twins scored about half a standard deviation higher in the character scales. Three of the four temperament dimensions (Novelty Seeking, Harm Avoidance, and Persistence had strong genetic and non-shared environmental effects, while Reward Dependence and the three character dimensions had moderate genetic effects, and both shared and non-shared environmental effects. CONCLUSIONS: Twins showed higher scores in character dimensions compared to adolescents from the general population. At least among adolescents there is a shared environmental influence for all of the character dimensions, but only for one of the temperament dimensions (i.e., Reward Dependence. This specific finding regarding the existence of shared environmental factors behind the character dimensions in adolescence, together with earlier findings showing a small shared environmental effects on character among young adults and no

  18. Study of twinning behavior of powder metallurgy Ti-Si alloy by interrupted in-situ tensile tests

    Energy Technology Data Exchange (ETDEWEB)

    Ye, X.X., E-mail: ye-xiaoxin@jwri.osaka-u.ac.jp [Joining and Welding Institute (JWRI), Osaka University (Japan); Imai, H.; Shen, J.H.; Chen, B. [Joining and Welding Institute (JWRI), Osaka University (Japan); Han, G.Q. [College of Materials Science and Engineering, Beijing University of Technology (China); Umeda, J.; Kondoh, K. [Joining and Welding Institute (JWRI), Osaka University (Japan)

    2017-01-02

    Twinning mechanism of powder metallurgy Ti-Si alloy was investigated by interrupted in-situ tensile tests. Extension twins {10−12}<10-1-1> in the fine-grained Ti-Si alloy were found in the uniform deformation period, but no twinning in the coarse pure Ti. Three deformation twinning nucleation mechanisms were proposed: i) local stress concentration by neighboured slip incompatibility, ii) slip/twin oriented relationship in the parent grain and iii) slip/twin transfer by high Luster-Morris oriented relationship. The interior back-stress state, grains rotation and dislocations pile-up drove the occurrence of detwinning phenomenon. Silicon-facilitation twinning verified the hypothesis that the substitutional Si solutes affected the core structures and thus the mobility of screw dislocations. Enhanced driving force and decreased energy barrier of nucleation in the micro/atomic scale were further proposed in the twinning activation. It was expected to deepen the understanding of twinning/detwinning behaviors and supply direct evidences building immature twinning mechanism. In-depth understanding about the relationship among the processing, mechanical properties and microstructure of Ti alloy was facilitated in the present work.

  19. Genetic and Environmental Influences on Pulmonary Function and Muscle Strength: The Chinese Twin Study of Aging

    DEFF Research Database (Denmark)

    Tian, Xiaocao; Xu, Chunsheng; Wu, Yili

    2017-01-01

    Genetic and environmental influences on predictors of decline in daily functioning, including forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), handgrip, and five-times-sit-to-stand test (FTSST), have not been addressed in the aging Chinese population. We performed classical twin...... was moderate for FEV1, handgrip, and FTSST (55-60%) but insignificant for FVC. Only FVC showed moderate control, with shared environmental factors accounting for about 50% of the total variance. In contrast, all measures of pulmonary function and muscle strength showed modest influences from the unique...

  20. The Impact of Preschool Twins' Physical Difficulties on Parental Perceptions towards Separation, Closeness and Friendship

    Science.gov (United States)

    Markodimitraki, Maria; Linardakis, Michalis; Kypriotaki, Maria; Manolitsis, George

    2016-01-01

    The aims of this study were to: (a) provide descriptive data of twins with physical difficulties among 120 Greek twins of preschool age; and (b) to investigate the impact of twins' health condition on parental perceptions towards twins' separation, closeness and friendship. The administration of School Policy for Twins and Higher Multiples…

  1. Thermodynamics of twinning

    International Nuclear Information System (INIS)

    Mueller, I.; Zak, G.

    1995-01-01

    The quasiplastic hysteresis occuring in shape memory alloys is associated with twinning in tension and compression, i.e. a conversion of one martensitic variant into antoher one. It shows the phenomena of internal elasticity and internal yield, heretofore studied extensively in pseudoelasticity. This paper presents experimental evidence of such phenomena and it offers partial explanation in identifying the onset of yield as an instability phenomenon due to coherency. That conjecture is motivated from a previous consideration of pseudoelasticity. (orig.)

  2. Fingerprint recognition with identical twin fingerprints.

    Science.gov (United States)

    Tao, Xunqiang; Chen, Xinjian; Yang, Xin; Tian, Jie

    2012-01-01

    Fingerprint recognition with identical twins is a challenging task due to the closest genetics-based relationship existing in the identical twins. Several pioneers have analyzed the similarity between twins' fingerprints. In this work we continue to investigate the topic of the similarity of identical twin fingerprints. Our study was tested based on a large identical twin fingerprint database that contains 83 twin pairs, 4 fingers per individual and six impressions per finger: 3984 (83*2*4*6) images. Compared to the previous work, our contributions are summarized as follows: (1) Two state-of-the-art fingerprint identification methods: P071 and VeriFinger 6.1 were used, rather than one fingerprint identification method in previous studies. (2) Six impressions per finger were captured, rather than just one impression, which makes the genuine distribution of matching scores more realistic. (3) A larger sample (83 pairs) was collected. (4) A novel statistical analysis, which aims at showing the probability distribution of the fingerprint types for the corresponding fingers of identical twins which have same fingerprint type, has been conducted. (5) A novel analysis, which aims at showing which finger from identical twins has higher probability of having same fingerprint type, has been conducted. Our results showed that: (a) A state-of-the-art automatic fingerprint verification system can distinguish identical twins without drastic degradation in performance. (b) The chance that the fingerprints have the same type from identical twins is 0.7440, comparing to 0.3215 from non-identical twins. (c) For the corresponding fingers of identical twins which have same fingerprint type, the probability distribution of five major fingerprint types is similar to the probability distribution for all the fingers' fingerprint type. (d) For each of four fingers of identical twins, the probability of having same fingerprint type is similar.

  3. Fingerprint recognition with identical twin fingerprints.

    Directory of Open Access Journals (Sweden)

    Xunqiang Tao

    Full Text Available Fingerprint recognition with identical twins is a challenging task due to the closest genetics-based relationship existing in the identical twins. Several pioneers have analyzed the similarity between twins' fingerprints. In this work we continue to investigate the topic of the similarity of identical twin fingerprints. Our study was tested based on a large identical twin fingerprint database that contains 83 twin pairs, 4 fingers per individual and six impressions per finger: 3984 (83*2*4*6 images. Compared to the previous work, our contributions are summarized as follows: (1 Two state-of-the-art fingerprint identification methods: P071 and VeriFinger 6.1 were used, rather than one fingerprint identification method in previous studies. (2 Six impressions per finger were captured, rather than just one impression, which makes the genuine distribution of matching scores more realistic. (3 A larger sample (83 pairs was collected. (4 A novel statistical analysis, which aims at showing the probability distribution of the fingerprint types for the corresponding fingers of identical twins which have same fingerprint type, has been conducted. (5 A novel analysis, which aims at showing which finger from identical twins has higher probability of having same fingerprint type, has been conducted. Our results showed that: (a A state-of-the-art automatic fingerprint verification system can distinguish identical twins without drastic degradation in performance. (b The chance that the fingerprints have the same type from identical twins is 0.7440, comparing to 0.3215 from non-identical twins. (c For the corresponding fingers of identical twins which have same fingerprint type, the probability distribution of five major fingerprint types is similar to the probability distribution for all the fingers' fingerprint type. (d For each of four fingers of identical twins, the probability of having same fingerprint type is similar.

  4. Experimental study on p-V indicator diagrams of twin-screw refrigeration compressor with economizer

    International Nuclear Information System (INIS)

    Wu Huagen; Peng Xueyuan; Xing Ziwen; Shu Pengcheng

    2004-01-01

    This paper presents the experimental investigation on the effects of the superfeed pressure together with economizer type on the performance of the twin-screw refrigeration compressor by means of the indicator diagram. With a pressure sensor embedded into the groove at the root of the female rotor on the discharge side, the pressure within the working chamber of a semi-hermetic twin-screw compressor with an economizer is recorded and then transformed into the indicator diagram. The results thus obtained are utilized to investigate the thermodynamic process of the compressor. It is shown that the compressor with an economizer has higher pressure during almost the whole compression process than without an economizer, resulting in the increase in the indicated power. Under different superfeed pressures, the pressure within the compression experiences different changes. This results in an optimal superfeed pressure for maximized compressor efficiency, which can be identified from the calculated compressor efficiency based on the indicator diagrams. It is also found that the pressure has a rapid increase at the beginning of superfeed process, and then a slow rise even a slight drop at the end of superfeed process, which is caused by the dynamic effect during superfeed process. Furthermore, if the superfeed pressure keeps the same, the pressure during compression in the compressor with the heat exchanger economizer is slightly higher than with the flash tank economizer, due to the higher temperature of superfeed refrigerant gas in the former case

  5. Application of hierarchical genetic models to Raven and WAIS subtests: a Dutch twin study.

    Science.gov (United States)

    Rijsdijk, Frühling V; Vernon, P A; Boomsma, Dorret I

    2002-05-01

    Hierarchical models of intelligence are highly informative and widely accepted. Application of these models to twin data, however, is sparse. This paper addresses the question of how a genetic hierarchical model fits the Wechsler Adult Intelligence Scale (WAIS) subtests and the Raven Standard Progressive test score, collected in 194 18-year-old Dutch twin pairs. We investigated whether first-order group factors possess genetic and environmental variance independent of the higher-order general factor and whether the hierarchical structure is significant for all sources of variance. A hierarchical model with the 3 Cohen group-factors (verbal comprehension, perceptual organisation and freedom-from-distractibility) and a higher-order g factor showed the best fit to the phenotypic data and to additive genetic influences (A), whereas the unique environmental source of variance (E) could be modeled by a single general factor and specifics. There was no evidence for common environmental influences. The covariation among the WAIS group factors and the covariation between the group factors and the Raven is predominantly influenced by a second-order genetic factor and strongly support the notion of a biological basis of g.

  6. Genetic and environmental relationships between change in weight and insulin resistance: the Healthy Twin Study.

    Science.gov (United States)

    Song, Yun-Mi; Lee, Kayoung; Sung, Joohon

    2014-06-01

    We aimed to investigate the association between weight change from 20 years of age and insulin resistance (IR), and genetic and environmental relationships between these traits. In 594 Korean twins and family members (209 men, 385 women, 44.0 ± 10.8 years old), the percentage of weight change was calculated using self-reported body weight at 20 years of age and currently measured bodyweight. IR traits were assessed using fasting plasma glucose and insulin, the homeostasis model assessment of IR index (HOMA-IR), and the quantitative insulin sensitivity check index (QUICKI). Linear mixed analysis was applied after adjusting for household, body mass index (BMI) at the age of 20 years, age, sex, alcohol, smoking, physical activity, and caloric intake. Heritabilities and genetic and environmental correlations were estimated after adjusting for covariates. In 55 monozygotic twin pairs discordant for HOMA-IR level by >0.3, a conditional logistic regression analysis was conducted regarding weight change. Increases in glucose, insulin, and HOMA-IR and a decrease in QUICKI were associated with a higher percentage of weight change (p change since 20 years old, after adjusting for lifestyle-related factors. In conclusion, both genetic and environmental influences played significant roles in the positive association between weight change from 20 years of age and IR.

  7. The effect of obstructive sleep apnea syndrome on growth and development in nonobese children: a parallel study of twins.

    Science.gov (United States)

    Zhang, Xiao Man; Shi, Jun; Meng, Guo Zhen; Chen, Hong Sai; Zhang, Li Na; Wang, Zhao Yan; Wu, Hao

    2015-03-01

    To explore the effects of obstructive sleep apnea syndrome (OSAS) on children's growth by the study of identical twins. Seventeen cases of nonobese children with OSAS were included in this study. The control group was their identical twin sibling, who had no signs of OSAS. Data including height, weight, and serum insulin-like growth factor 1 levels were analyzed before tonsillectomy and adenoidectomy (T&A) and at 3, 6, and 12 months after surgery. The mean apnea hyponea index was 3.9 times/hour in patients with OSAS and became normal after surgery. Minimum oxygen saturation gradually increased after T&A. The height and weight of the OSAS group before T&A was lower than the control group. During the follow-up period, height and weight increased but were lower than the control group. Serum insulin-like growth factor 1 levels in the OSAS group before T&A were lower than the control group. The level was significantly increased 3 months after T&A. OSAS impairs growth and development. Significant growth recovery occurs after T&A, and early surgical intervention is an important factor for improvement in growth. Copyright © 2015. Published by Elsevier Inc.

  8. Genetic and environmental influences on temperament in the first year of life: the Puerto Rico Infant Twin Study (PRINTS).

    Science.gov (United States)

    Silberg, Judy L; Miguel, Vivian Febo San; Murrelle, E Lenn; Prom, Elizabeth; Bates, John E; Canino, Glorisa; Egger, Helen; Eaves, Lindon J

    2005-08-01

    Three dimensions of temperament -- difficult temperament, unadaptablility and unsociability -- were assessed in the first year of life by maternal interview in twins born in Puerto Rico during 2001 and 2002. Eight hundred and sixty-five eligible mothers (80%) were traced and interviewed. Model-fitting results showed that additive genetic factors and the individual specific environment contributed to variation in all three dimensions. In addition, the pattern of variances and correlations suggested that sibling contrast effects influence ratings of difficult temperament. Moderate effects of the shared environment contributed to ratings of adaptability and sociability. There was a significant genetic correlation between difficult temperament and unadaptability. Genetic and environmental effects do not differ significantly between boys and girls. The study is the first population-based study of Puerto Rican twins and one of few to attempt the assessment of behavior in the first year. Preliminary results for difficult temperament and sociability were consistent with those in other populations and ages. In contrast, a significant effect of the shared environment on the temperamental trait of unadaptability has not been reported previously.

  9. Study of 3-D stress development in parent and twin pairs of a hexagonal close-packed polycrystal: Part II – crystal plasticity finite element modeling

    International Nuclear Information System (INIS)

    Abdolvand, Hamidreza; Majkut, Marta; Oddershede, Jette; Wright, Jonathan P.; Daymond, Mark R.

    2015-01-01

    Stress heterogeneity within each individual grain of polycrystalline Zircaloy-2 is studied using a crystal plasticity finite element (CPFE) model. For this purpose, the weighted Voronoi tessellation method is used to construct 3D geometries of more than 2600 grains based on their center-of-mass positions and volumes as measured by three-dimensional X-ray diffraction (3DXRD) microscopy. The constructed microstructure is meshed with different element densities and for different numbers of grains. Then a selected group of twin and parent pairs are studied. It is shown that the measured average stress for each grain from the 3DXRD experiment is within the stress variation zone of the grain modeled in the CPFE simulation. Also, the CPFE average stress calculation for each grain is in good agreement with the measured average stress values. It is shown that upon considering the stress variations within each grain, stresses in the parent and twin are quite different if they are plotted in the global coordinate system. However, if the stress tensor is rotated into the local coordinate system of the twin habit plane, all the stress components averaged over the presented population are close, except for the shear acting on the twin plane and the transverse stress. This result is significant as it provides information needed to model such parent-twin interactions in crystal plasticity codes

  10. Twin pregnancy possibly associated with high semen quality

    DEFF Research Database (Denmark)

    Asklund, Camilla; Jensen, Tina Kold; Jørgensen, Niels

    2007-01-01

    BACKGROUND: Recent studies found an association between a long waiting time to pregnancy (TTP) and reduced probability of twinning and a reduced dizygotic (DZ) twinning rate in subfertile men. However, it remains unsolved whether semen quality is associated with twin offspring. We therefore studied...... the semen quality in a group of fathers of naturally conceived twins. METHODS: In this study, 37 fathers of DZ twins and 15 fathers of monozygotic (MZ) twins participated, and 349 normal fertile men served as a reference group. All men delivered a semen sample, underwent a physical examination and completed...... points higher than the reference group (P semen quality than the reference group, which supports...

  11. Twin studies reveal specific imbalances in the mucosa-associated microbiota of patients with ileal Crohn's disease

    Energy Technology Data Exchange (ETDEWEB)

    Willing, B.; Halfvarson, J.; Dicksved, J.; Rosenquist, M.; Jarnerot, G.; Engstrand, L.; Tysk, C.; Jansson, J. K

    2008-08-15

    Large inter-individual variation in the composition of the intestinal microbiota between unrelated individuals has made it challenging to identify specific aspects of dysbiosis that lead to Crohn's disease. To reduce variations in exposure during establishment of the gut flora and influence of genotype, we studied the mucosaassociated microbiota of monozygotic twin pairs that were discordant (n=6) or concordant (n=4) for Crohn's disease. DNA was extracted from biopsies collected from 5 locations between the ileum and rectum. Bacterial 16S ribosomal RNA genes were amplified and community composition assessed by terminal-restriction fragment length polymorphism, cloning and sequencing and quantitative real-time PCR. The microbial compositions at all biopsy locations for each individual were similar, regardless of disease state, but there were differences between individuals. In particular, individuals with predominantly ileal Crohn's had a dramatically lower abundance (P<0.001) of Faecalibacterium prausnitzii and increased abundance (P<0.03) of Escherichia coli compared to healthy co-twins and those with Crohn's localized in the colon. This dysbiosis was significantly correlated to the disease phenotype rather than genotype. The reduced abundance of F. prausnitzii and increased abundance of E. coli are indicative of an ileal Crohn's disease phenotype, distinct from colonic Crohn's disease and the relative abundances of these specific bacterial populations are promising biomarker candidates for differential diagnosis of Crohn's and eventually customized treatment.

  12. New insights into the endophenotypic status of cognition in bipolar disorder: genetic modelling study of twins and siblings.

    Science.gov (United States)

    Georgiades, Anna; Rijsdijk, Fruhling; Kane, Fergus; Rebollo-Mesa, Irene; Kalidindi, Sridevi; Schulze, Katja K; Stahl, Daniel; Walshe, Muriel; Sahakian, Barbara J; McDonald, Colm; Hall, Mei-Hua; Murray, Robin M; Kravariti, Eugenia

    2016-06-01

    Twin studies have lacked statistical power to apply advanced genetic modelling techniques to the search for cognitive endophenotypes for bipolar disorder. To quantify the shared genetic variability between bipolar disorder and cognitive measures. Structural equation modelling was performed on cognitive data collected from 331 twins/siblings of varying genetic relatedness, disease status and concordance for bipolar disorder. Using a parsimonious AE model, verbal episodic and spatial working memory showed statistically significant genetic correlations with bipolar disorder (rg = |0.23|-|0.27|), which lost statistical significance after covarying for affective symptoms. Using an ACE model, IQ and visual-spatial learning showed statistically significant genetic correlations with bipolar disorder (rg = |0.51|-|1.00|), which remained significant after covarying for affective symptoms. Verbal episodic and spatial working memory capture a modest fraction of the bipolar diathesis. IQ and visual-spatial learning may tap into genetic substrates of non-affective symptomatology in bipolar disorder. © The Royal College of Psychiatrists 2016.

  13. Heritability and mortality risk of insomnia-related symptoms: a genetic epidemiologic study in a population-based twin cohort.

    Science.gov (United States)

    Hublin, Christer; Partinen, Markku; Koskenvuo, Markku; Kaprio, Jaakko

    2011-07-01

    Our aim was to estimate heritability in phenotypic insomnia and the association between insomnia and mortality. Representative follow-up study. 1990 survey of the Finnish Twin Cohort (N = 12502 adults; 1554 monozygotic and 2991 dizygotic twin pairs). Current insomnia-related symptoms (insomnia in general, difficulty in initiating sleep, sleep latency, nocturnal awakening, early morning awakening, and non-restorative sleep assessed in the morning and during the day) were asked. Latent class analysis was used to classify subjects into different sleep quality classes. Quantitative genetic modelling was used to estimate heritability. Mortality data was obtained from national registers until end of April 2009. The heritability estimates of each symptom were similar in both genders varying from 34% (early morning awakening) to 45% (nocturnal awakening). The most parsimonious latent class analysis produced 3 classes: good sleepers (48%), average sleepers (up to weekly symptoms, 40%), and poor sleepers (symptoms daily or almost daily, 12%). The heritability estimate for the cluster was 46% (95% confidence interval 41% to 50%). In a model adjusted for smoking, BMI, and depressive symptoms, the all-cause mortality of poor sleepers was elevated (excess mortality 55% in men and 51% in women). Further adjustment for sleep length, use of sleep promoting medications, and sleep apnea-related symptoms did not change the results. Insomnia-related symptoms were common in both genders. The symptoms and their clusters showed moderate heritability estimates. A significant association was found between poor sleep and risk of mortality, especially in those with somatic disease.

  14. Persistence and innovation effects in genetic and environmental factors in negative emotionality during infancy: A twin study.

    Directory of Open Access Journals (Sweden)

    Lyndall Schumann

    Full Text Available Difficult temperament in infancy is a risk factor for forms of later internalizing and externalizing psychopathology, including depression and anxiety. A better understanding of the roots of difficult temperament requires assessment of its early development with a genetically informative design. The goal of this study was to estimate genetic and environmental contributions to individual differences in infant negative emotionality, their persistence over time and their influences on stability between 5 and 18 months of age.Participants were 244 monozygotic and 394 dizygotic twin pairs (49.7% male recruited from birth. Mothers rated their twins for negative emotionality at 5 and 18 months. Longitudinal analysis of stability and innovation between the two time points was performed in Mplus.There were substantial and similar heritability (approximately 31% and shared environmental (57.3% contributions to negative emotionality at both 5 and 18 months. The trait's interindividual stability across time was both genetically- and environmentally- mediated. Evidence of innovative effects (i.e., variance at 18 months independent from variance at 5 months indicated that negative emotionality is developmentally dynamic and affected by persistent and new genetic and environmental factors at 18 months.In the first two years of life, ongoing genetic and environmental influences support temperamental negative emotionality but new genetic and environmental factors also indicate dynamic change of those factors across time. A better understanding of the source and timing of factors on temperament in early development, and role of sex, could improve efforts to prevent related psychopathology.

  15. Does the Environment Have an Enduring Effect on ADHD? A Longitudinal Study of Monozygotic Twin Differences in Children.

    Science.gov (United States)

    Livingstone, Luisa T; Coventry, William L; Corley, Robin P; Willcutt, Erik G; Samuelsson, Stefan; Olson, Richard K; Byrne, Brian

    2016-11-01

    Environmental factors play a key role in the development of Attention-Deficit/Hyperactivity Disorder (ADHD), but the long-term effects of these factors are still unclear. This study analyses data from 1024 monozygotic (identical) twins in Australia, the United States, and Scandinavia who were assessed for ADHD in Preschool, Kindergarten, Grade 1, and Grade 2. Differences within each twin pair were used as a direct measure of non-shared environmental effects. The Trait-State-Occasion (TSO) model developed by Cole et al. (Psychological Methods, 10, 3-20, 2005) was used to separate the non-shared environmental effects into stable factors, and transient factors that excluded measurement error. Stable factors explained, on average, 44 % and 39 % of the environmental variance in hyperactive-impulsive and inattentive symptoms, respectively. Transient effects explained the remaining 56 % and 60 % of variance. The proportion of stable variance was higher than expected based on previous research, suggesting promise for targeted interventions if future research identifies these stable risk factors.

  16. Playing a Musical Instrument as a Protective Factor against Dementia and Cognitive Impairment: A Population-Based Twin Study

    Directory of Open Access Journals (Sweden)

    M. Alison Balbag

    2014-01-01

    Full Text Available Increasing evidence supports that playing a musical instrument may benefit cognitive development and health at young ages. Whether playing an instrument provides protection against dementia has not been established. In a population-based cotwin control study, we examined the association between playing a musical instrument and whether or not the twins developed dementia or cognitive impairment. Participation in playing an instrument was taken from informant-based reports of twins’ leisure activities. Dementia diagnoses were based on a complete clinical workup using standard diagnostic criteria. Among 157 twin pairs discordant for dementia and cognitive impairment, 27 pairs were discordant for playing an instrument. Controlling for sex, education, and physical activity, playing a musical instrument was significantly associated with less likelihood of dementia and cognitive impairment (odds ratio [OR] = 0.36 [95% confidence interval 0.13–0.99]. These findings support further consideration of music as a modifiable protective factor against dementia and cognitive impairment.

  17. Genetic and environmental variances of bone microarchitecture and bone remodeling markers: a twin study.

    Science.gov (United States)

    Bjørnerem, Åshild; Bui, Minh; Wang, Xiaofang; Ghasem-Zadeh, Ali; Hopper, John L; Zebaze, Roger; Seeman, Ego

    2015-03-01

    All genetic and environmental factors contributing to differences in bone structure between individuals mediate their effects through the final common cellular pathway of bone modeling and remodeling. We hypothesized that genetic factors account for most of the population variance of cortical and trabecular microstructure, in particular intracortical porosity and medullary size - void volumes (porosity), which establish the internal bone surface areas or interfaces upon which modeling and remodeling deposit or remove bone to configure bone microarchitecture. Microarchitecture of the distal tibia and distal radius and remodeling markers were measured for 95 monozygotic (MZ) and 66 dizygotic (DZ) white female twin pairs aged 40 to 61 years. Images obtained using high-resolution peripheral quantitative computed tomography were analyzed using StrAx1.0, a nonthreshold-based software that quantifies cortical matrix and porosity. Genetic and environmental components of variance were estimated under the assumptions of the classic twin model. The data were consistent with the proportion of variance accounted for by genetic factors being: 72% to 81% (standard errors ∼18%) for the distal tibial total, cortical, and medullary cross-sectional area (CSA); 67% and 61% for total cortical porosity, before and after adjusting for total CSA, respectively; 51% for trabecular volumetric bone mineral density (vBMD; all p accounted for 47% to 68% of the variance (all p ≤ 0.001). Cross-twin cross-trait correlations between tibial cortical porosity and medullary CSA were higher for MZ (rMZ  = 0.49) than DZ (rDZ  = 0.27) pairs before (p = 0.024), but not after (p = 0.258), adjusting for total CSA. For the remodeling markers, the data were consistent with genetic factors accounting for 55% to 62% of the variance. We infer that middle-aged women differ in their bone microarchitecture and remodeling markers more because of differences in their genetic factors than

  18. Gene-Environment Interplay in Twin Models

    OpenAIRE

    Verhulst, Brad; Hatemi, Peter K.

    2013-01-01

    In this article, we respond to Shultziner’s critique that argues that identical twins are more alike not because of genetic similarity, but because they select into more similar environments and respond to stimuli in comparable ways, and that these effects bias twin model estimates to such an extent that they are invalid. The essay further argues that the theory and methods that undergird twin models, as well as the empirical studies which rely upon them, are unaware of these potential biases...

  19. The NordiNet® International Outcome Study and NovoNet® ANSWER Program®: rationale, design, and methodology of two international pharmacoepidemiological registry-based studies monitoring long-term clinical and safety outcomes of growth hormone therapy (Norditropin®).

    Science.gov (United States)

    Höybye, Charlotte; Sävendahl, Lars; Christesen, Henrik Thybo; Lee, Peter; Pedersen, Birgitte Tønnes; Schlumpf, Michael; Germak, John; Ross, Judith

    2013-01-01

    Randomized controlled trials have shown that growth hormone (GH) therapy has effects on growth, metabolism, and body composition. GH therapy is prescribed for children with growth failure and adults with GH deficiency. Carefully conducted observational study of GH treatment affords the opportunity to assess long-term treatment outcomes and the clinical factors and variables affecting those outcomes, in patients receiving GH therapy in routine clinical practice. The NordiNet® International Outcome Study (IOS) and the American Norditropin® Web Enabled Research (ANSWER Program®) are two complementary, non-interventional, observational studies that adhere to current guidelines for pharmacoepidemiological data. The studies include pediatric and adult patients receiving Norditropin®, as prescribed by their physicians. The studies gather long-term data on the safety and effectiveness of reallife treatment with the recombinant human GH, Norditropin®. We describe the origins, aims, objectives, and design methodology of the studies, as well as their governance and validity, strengths, and limitations. The NordiNet® IOS and ANSWER Program® studies will provide valid insights into the effectiveness and safety of GH treatment across a diverse and large patient population treated in accordance with real-world clinical practice and following the Good Pharmacoepidemiological Practice and STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) guidelines.

  20. I think, therefore I am: a twin study of attributional style in adolescents.

    Science.gov (United States)

    Lau, Jennifer Y F; Rijsdijk, Frühling; Eley, Thalia C

    2006-07-01

    Parenting factors may be important to the development of attributional style in adolescence, which in turn relates to depression symptoms. These relationships have mainly been considered in terms of social risk mechanisms, and little is known about the role of genetic influences. Self-reported measures of attributional style, depression symptoms and parental disciplinary styles were administered to over 1300 adolescent twin and sibling pairs. Model-fitting techniques were used to examine the role of genetic and environmental influences. Moderate genetic influences on attributional style were demonstrated, and furthermore, its association with depression reflected considerable genetic effects. Familial factors were implicated in the association between attributional style and punitive parenting, although genetic from shared environmental causes could not be distinguished. Our results demonstrate that attributional style is influenced by genetic, as well as social factors. Implications for aetiological pathways integrating cognitive, genetic and social factors on adolescent depression are discussed.

  1. Comparative study of social skills observation of twin with and without visual impairment

    Directory of Open Access Journals (Sweden)

    Carolina Severino Lopes da Costa

    2012-03-01

    Full Text Available The general aim was to describe and characterize the social performances of two identical twins aged ten years old: one blind and one sighted. The data were obtained by filming the children during free situations. According to a protocol for observing the free situations, the films were assessed so that the children’s performances enabled to infer the categories of social skills. The results showed that the sighted child presented a wider and more refined repertoire of social skills in relation to her sister. From the data, it is possible to conclude, in this case, that blind and sighted children have distinct social skills repertories, and the existing differences can be related to the blind variable as well as to the differences in the way the environment stimulates the children.

  2. A longitudinal twin study of borderline and antisocial personality disorder traits in early to middle adulthood.

    Science.gov (United States)

    Reichborn-Kjennerud, T; Czajkowski, N; Ystrøm, E; Ørstavik, R; Aggen, S H; Tambs, K; Torgersen, S; Neale, M C; Røysamb, E; Krueger, R F; Knudsen, G P; Kendler, K S

    2015-10-01

    Antisocial personality disorder (ASPD) and borderline personality disorder (BPD) share genetic and environmental risk factors. Little is known about the temporal stability of these etiological factors in adulthood. DSM-IV criteria for ASPD and BPD were assessed using structured interviews in 2282 Norwegian twins in early adulthood and again approximately 10 years later. Longitudinal biometric models were used to analyze the number of endorsed criteria. The mean criterion count for ASPD and BPD decreased 40% and 28%, respectively, from early to middle adulthood. Rank-order stability was 0.58 for ASPD and 0.45 for BPD. The best-fitting longitudinal twin model included only genetic and individual-specific environmental factors. Genetic effects, both those shared by ASPD and BPD, and those specific to each disorder remained completely stable. The unique environmental effects, however, changed substantially, with a correlation across time of 0.19 for the shared effects, and 0.39 and 0.15, respectively, for those specific to ASPD and BPD. Genetic effects accounted for 71% and 72% of the stability over time for ASPD and BPD, respectively. The genetic and environmental correlations between ASPD and BPD were 0.73, and 0.43, respectively, at both time points. ASPD and BPD traits were moderately stable from early to middle adulthood, mostly due to genetic risk factors which did not change over the 10-year assessment period. Environmental risk factors were mostly transient, and appear to be the main source of phenotypic change. Genetic liability factors were, to a large extent, shared by ASPD and BPD.

  3. A longitudinal twin study of the direction of effects between ADHD symptoms and IQ.

    Science.gov (United States)

    Rommel, Anna Sophie; Rijsdijk, Frühling; Greven, Corina U; Asherson, Philip; Kuntsi, Jonna

    2015-01-01

    While the negative association between ADHD symptoms and IQ is well documented, our knowledge about the direction and aetiology of this association is limited. Here, we examine the association of ADHD symptoms with verbal and performance IQ longitudinally in a population-based sample of twins. In a population-based sample of 4,771 twin pairs, DSM-IV ADHD symptoms were obtained from the Conners' Parent Rating Scale-Revised. Verbal (vocabulary) and performance (Raven's Progressive Matrices) IQ were assessed online. ADHD symptom ratings and IQ scores were obtained at ages 12, 14 and 16 years. Making use of the genetic sensitivity and time-ordered nature of our data, we use a cross-lagged model to examine the direction of effects, while modelling the aetiologies of the association between ADHD symptoms with vocabulary and Raven's scores over time. Although time-specific aetiological influences emerged for each trait at ages 14 and 16 years, the aetiological factors involved in the association between ADHD symptoms and IQ were stable over time. ADHD symptoms and IQ scores significantly predicted each other over time. ADHD symptoms at age 12 years were a significantly stronger predictor of vocabulary and Raven's scores at age 14 years than vice versa, whereas no differential predictive effects emerged from age 14 to 16 years. The results suggest that ADHD symptoms may put adolescents at risk for decreased IQ scores. Persistent genetic influences seem to underlie the association of ADHD symptoms and IQ over time. Early intervention is likely to be key to reducing ADHD symptoms and the associated risk for lower IQ.

  4. Sex differences in the pathways to major depression: a study of opposite-sex twin pairs.

    Science.gov (United States)

    Kendler, Kenneth S; Gardner, Charles O

    2014-04-01

    The authors sought to clarify the nature of sex differences in the etiologic pathways to major depression. Retrospective and prospective assessments of 20 developmentally organized risk factors and the occurrence of past-year major depression were conducted at two waves of personal interviews at least 12 months apart in 1,057 opposite-sex dizygotic twin pairs from a population-based register. Analyses were conducted by structural modeling, examining within-pair differences. Sixty percent of all paths in the best-fit model exhibited sex differences. Eleven of the 20 risk factors differed across sexes in their impact on liability to major depression. Five had a greater impact in women: parental warmth, neuroticism, divorce, social support, and marital satisfaction. Six had a greater impact in men: childhood sexual abuse, conduct disorder, drug abuse, prior history of major depression, and distal and dependent proximal stressful life events. The life event categories responsible for the stronger effect in males were financial, occupational, and legal in nature. In a co-twin control design, which matches sisters and brothers on genetic and familial-environmental background, personality and failures in interpersonal relationships played a stronger etiologic role in major depression for women than for men. Externalizing psychopathology, prior depression, and specific "instrumental" classes of acute stressors were more important in the etiologic pathway to major depression for men. The results are consistent with previously proposed typologies of major depression that suggest two subtypes that differ in prevalence in women (deficiencies in caring relationships and interpersonal loss) and men (failures to achieve expected goals, with lowered self-worth).

  5. Rapid video-referenced ratings of reciprocal social behavior in toddlers: a twin study.

    Science.gov (United States)

    Marrus, Natasha; Glowinski, Anne L; Jacob, Theodore; Klin, Ami; Jones, Warren; Drain, Caroline E; Holzhauer, Kieran E; Hariprasad, Vaishnavi; Fitzgerald, Robert T; Mortenson, Erika L; Sant, Sayli M; Cole, Lyndsey; Siegel, Satchel A; Zhang, Yi; Agrawal, Arpana; Heath, Andrew C; Constantino, John N

    2015-12-01

    Reciprocal social behavior (RSB) is a developmental prerequisite for social competency, and deficits in RSB constitute a core feature of autism spectrum disorder (ASD). Although clinical screeners categorically ascertain risk of ASD in early childhood, rapid methods for quantitative measurement of RSB in toddlers are not yet established. Such measurements are critical for tracking developmental trajectories and incremental responses to intervention. We developed and validated a 20-min video-referenced rating scale, the video-referenced rating of reciprocal social behavior (vrRSB), for untrained caregivers to provide standardized ratings of quantitative variation in RSB. Parents of 252 toddler twins [Monozygotic (MZ) = 31 pairs, Dizygotic (DZ) = 95 pairs] ascertained through birth records, rated their twins' RSB at two time points, on average 6 months apart, and completed two developmental measures, the Modified Checklist for Autism in Toddlers (M-CHAT) and the MacArthur Communicative Development Inventory Short Form (MCDI-s). Scores on the vrRSB were fully continuously distributed, with excellent 6-month test-retest reliability ([intraclass correlation coefficient] ICC = 0.704, p CHAT (t = -8.588, df = 31, p < .000), incrementally improved from 18-24 months, and were inversely correlated with receptive and expressive vocabulary on the MCDI-s. Like quantitative autistic trait ratings in school-aged children and adults, toddler scores on the vrRSB are continuously distributed and appear highly heritable. These ratings exhibited minimal measurement error, high inter-individual stability, and developmental progression in RSB as children matured from 18-24 months, supporting their potential utility for serially quantifying the severity of early autistic syndromes over time and in response to intervention. In addition, these findings inform the genetic-environmental structure of RSB in early typical development. © 2015 Association for Child and

  6. A longitudinal twin study of the direction of effects between ADHD symptoms and IQ.

    Directory of Open Access Journals (Sweden)

    Anna Sophie Rommel

    Full Text Available While the negative association between ADHD symptoms and IQ is well documented, our knowledge about the direction and aetiology of this association is limited. Here, we examine the association of ADHD symptoms with verbal and performance IQ longitudinally in a population-based sample of twins. In a population-based sample of 4,771 twin pairs, DSM-IV ADHD symptoms were obtained from the Conners' Parent Rating Scale-Revised. Verbal (vocabulary and performance (Raven's Progressive Matrices IQ were assessed online. ADHD symptom ratings and IQ scores were obtained at ages 12, 14 and 16 years. Making use of the genetic sensitivity and time-ordered nature of our data, we use a cross-lagged model to examine the direction of effects, while modelling the aetiologies of the association between ADHD symptoms with vocabulary and Raven's scores over time. Although time-specific aetiological influences emerged for each trait at ages 14 and 16 years, the aetiological factors involved in the association between ADHD symptoms and IQ were stable over time. ADHD symptoms and IQ scores significantly predicted each other over time. ADHD symptoms at age 12 years were a significantly stronger predictor of vocabulary and Raven's scores at age 14 years than vice versa, whereas no differential predictive effects emerged from age 14 to 16 years. The results suggest that ADHD symptoms may put adolescents at risk for decreased IQ scores. Persistent genetic influences seem to underlie the association of ADHD symptoms and IQ over time. Early intervention is likely to be key to reducing ADHD symptoms and the associated risk for lower IQ.

  7. The relationship between parental depressive symptoms and offspring psychopathology: evidence from a children-of-twins study and an adoption study.

    Science.gov (United States)

    McAdams, T A; Rijsdijk, F V; Neiderhiser, J M; Narusyte, J; Shaw, D S; Natsuaki, M N; Spotts, E L; Ganiban, J M; Reiss, David; Leve, L D; Lichtenstein, P; Eley, T C

    2015-01-01

    Parental depressive symptoms are associated with emotional and behavioural problems in offspring. However, genetically informative studies are needed to distinguish potential causal effects from genetic confounds, and longitudinal studies are required to distinguish parent-to-child effects from child-to-parent effects. We conducted cross-sectional analyses on a sample of Swedish twins and their adolescent offspring (n = 876 twin families), and longitudinal analyses on a US sample of children adopted at birth, their adoptive parents, and their birth mothers (n = 361 adoptive families). Depressive symptoms were measured in parents, and externalizing and internalizing problems measured in offspring. Structural equation models were fitted to the data. Results of model fitting suggest that associations between parental depressive symptoms and offspring internalizing and externalizing problems remain after accounting for genes shared between parent and child. Genetic transmission was not evident in the twin study but was evident in the adoption study. In the longitudinal adoption study child-to-parent effects were evident. We interpret the results as demonstrating that associations between parental depressive symptoms and offspring emotional and behavioural problems are not solely attributable to shared genes, and that bidirectional effects may be present in intergenerational associations.

  8. Piloted simulation study of an ILS approach of a twin-pusher business/commuter turboprop aircraft configuration

    Science.gov (United States)

    Riley, Donald R.; Brandon, Jay M.; Glaab, Louis J.

    1994-01-01

    A six-degree-of-freedom nonlinear simulation of a twin-pusher, turboprop business/commuter aircraft configuration representative of the Cessna ATPTB (Advanced turboprop test bed) was developed for use in piloted studies with the Langley General Aviation Simulator. The math models developed are provided, simulation predictions are compared with with Cessna flight-test data for validation purposes, and results of a handling quality study during simulated ILS (instrument landing system) approaches and missed approaches are presented. Simulated flight trajectories, task performance measures, and pilot evaluations are presented for the ILS approach and missed-approach tasks conducted with the vehicle in the presence of moderate turbulence, varying horizontal winds and engine-out conditions. Six test subjects consisting of two research pilots, a Cessna test pilot, and three general aviation pilots participated in the study. This effort was undertaken in cooperation with the Cessna Aircraft Company.

  9. Smoking status of parents, siblings and friends: Predictors of regular smoking? Findings from a longitudinal twin-family study

    NARCIS (Netherlands)

    Vink, J.M.; Willemsen, G.; Engels, R.C.M.E.; Boomsma, D.I.

    2003-01-01

    The relationship between regular smoking behavior and the smoking behavior of parents, siblings and friends was investigated using data from the Netherlands Twin Register. Cross-sectional analyses of data of 3906 twins showed significant associations between smoking behavior of the participant and

  10. Incidence of and risk factors for severe maternal complications associated with hypertensive disorders after 36 weeks' gestation in uncomplicated twin pregnancies: A prospective cohort study.

    Science.gov (United States)

    Yamamoto, Ryo; Ishii, Keisuke; Muto, Haruka; Ota, Shiyo; Kawaguchi, Haruna; Hayashi, Shusaku; Mitsuda, Nobuaki

    2018-04-19

    To elucidate the incidence of and risk factors for severe hypertensive disorders (HD) and related maternal complications in uncomplicated twin pregnancies that reached 36 weeks' gestation. We conducted a prospective cohort study of twin pregnancies delivered after 36 weeks' gestation. Cases of twin-twin transfusion syndrome, twin anemia-polycythemia sequence, malformed fetuses, monoamniotic twins, selective reduction, fetal therapy and HD or fetal death before 35 weeks' gestation were excluded. The study's primary outcome was the incidence of severe maternal complications, including severe HD, eclampsia, placental abruption, HELLP (hemolysis, elevated liver enzyme and low platelet) syndrome, pulmonary edema and cerebrovascular disease. Perinatal factors associated with the primary outcome were identified using a multivariate logistic regression model. In 330 enrolled women, the number of cases with the primary outcome was 28 (8.5%; 95% confidence interval 5.9-12.0), including 25 cases of severe HD and each one case of placental abruption, HELLP syndrome and eclampsia. The rate of severe maternal complications significantly increased with gestational age, demonstrating 1.2% at 36 weeks, 3.9% at 37 weeks and 6.4% at 38 weeks. Only gestational proteinuria was identified as the independent risk factor for severe maternal complications (adjusted odds ratio 17.1 [95% confidence interval 6.71-45.4]). Severe maternal HD and related complications increased from late preterm to early term; particularly, patients with gestational proteinuria were at high risk. © 2018 Japan Society of Obstetrics and Gynecology.

  11. The utility of twins in developmental cognitive neuroscience research: How twins strengthen the ABCD research design.

    Science.gov (United States)

    Iacono, William G; Heath, Andrew C; Hewitt, John K; Neale, Michael C; Banich, Marie T; Luciana, Monica M; Madden, Pamela A; Barch, Deanna M; Bjork, James M

    2018-08-01

    The ABCD twin study will elucidate the genetic and environmental contributions to a wide range of mental and physical health outcomes in children, including substance use, brain and behavioral development, and their interrelationship. Comparisons within and between monozygotic and dizygotic twin pairs, further powered by multiple assessments, provide information about genetic and environmental contributions to developmental associations, and enable stronger tests of causal hypotheses, than do comparisons involving unrelated children. Thus a sub-study of 800 pairs of same-sex twins was embedded within the overall Adolescent Brain and Cognitive Development (ABCD) design. The ABCD Twin Hub comprises four leading centers for twin research in Minnesota, Colorado, Virginia, and Missouri. Each site is enrolling 200 twin pairs, as well as singletons. The twins are recruited from registries of all twin births in each State during 2006-2008. Singletons at each site are recruited following the same school-based procedures as the rest of the ABCD study. This paper describes the background and rationale for the ABCD twin study, the ascertainment of twin pairs and implementation strategy at each site, and the details of the proposed analytic strategies to quantify genetic and environmental influences and test hypotheses critical to the aims of the ABCD study. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  12. Monochorionic twin pregnancies

    NARCIS (Netherlands)

    Hack, K.E.A.

    2008-01-01

    Following widespread application of assisted reproductive technology modalities and the increased age of motherhood, the incidence of twin gestations has increased markedly. Twins are either monozygotic or dizygotic. Dizygotic (i.e. fraternal) twins result from the fertilization of two different

  13. Exotic quarks in Twin Higgs models

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Hsin-Chia [Department of Physics, University of California, Davis,One Shields Avenue, Davis, CA 95616 (United States); Jung, Sunghoon [School of Physics, Korea Institute for Advanced Study,85 Hoegiro, Dongdaemun-gu, Seoul 130-722 (Korea, Republic of); SLAC National Accelerator Laboratory,2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Salvioni, Ennio [Department of Physics, University of California, Davis,One Shields Avenue, Davis, CA 95616 (United States); Tsai, Yuhsin [Department of Physics, University of California, Davis,One Shields Avenue, Davis, CA 95616 (United States); Maryland Center for Fundamental Physics,Department of Physics, University of Maryland,College Park, MD 20742 (United States)

    2016-03-14

    The Twin Higgs model provides a natural theory for the electroweak symmetry breaking without the need of new particles carrying the standard model gauge charges below a few TeV. In the low energy theory, the only probe comes from the mixing of the Higgs fields in the standard model and twin sectors. However, an ultraviolet completion is required below ∼ 10 TeV to remove residual logarithmic divergences. In non-supersymmetric completions, new exotic fermions charged under both the standard model and twin gauge symmetries have to be present to accompany the top quark, thus providing a high energy probe of the model. Some of them carry standard model color, and may therefore be copiously produced at current or future hadron colliders. Once produced, these exotic quarks can decay into a top together with twin sector particles. If the twin sector particles escape the detection, we have the irreducible stop-like signals. On the other hand, some twin sector particles may decay back into the standard model particles with long lifetimes, giving spectacular displaced vertex signals in combination with the prompt top quarks. This happens in the Fraternal Twin Higgs scenario with typical parameters, and sometimes is even necessary for cosmological reasons. We study the potential displaced vertex signals from the decays of the twin bottomonia, twin glueballs, and twin leptons in the Fraternal Twin Higgs scenario. Depending on the details of the twin sector, the exotic quarks may be probed up to ∼ 2.5 TeV at the LHC and beyond 10 TeV at a future 100 TeV collider, providing a strong test of this class of ultraviolet completions.

  14. Methadone treatments in a Swiss Region, 2001–2008: a registry-based analysis

    Directory of Open Access Journals (Sweden)

    Huissoud Thérèse

    2012-12-01

    Full Text Available Abstract Background To determine, in a region of Switzerland, the duration of retention in opioid substitution treatments with methadone (OSTM, duration of treatment interruptions, probability of re-entry to treatment after a treatment interruption, and associated factors. Methods A secondary analysis of registry-based data was performed with patients (n = 2880 registered in the methadone treatment register database of the Public Health Service of the canton of Vaud between January 1, 2001 and June 30, 2008. Survival analysis and multivariate analysis was conducted. Results The probability of remaining on treatment was 69% at 1 year and 45% at 3 years (n =1666. One-third of patients remained on treatment beyond 5 years. The estimated hazard of leaving treatment was increased by a ratio of 1.31 in the case of a first treatment (P = 0.001, 1.83 for those without a fixed home (P P n = 1581. Factors at the interruption of treatment associated with a higher probability of re-entering were: interruption not due to methadone withdrawal, bad physical health, and higher methadone dose. Conclusions OSTM are long-term (maintenance treatments in Switzerland. Younger age, bad living conditions at entry, and first treatment are predictors of lower retention. Approximately one-half of patients who interrupt treatment will re-enter treatment within 5 years.

  15. Family-Based Treatment of a 17-Year-Old Twin Presenting with Emerging Anorexia Nervosa: A Case Study Using the "Maudsley Method"

    Science.gov (United States)

    Loeb, Katharine L.; Hirsch, Alicia M.; Greif, Rebecca; Hildebrandt, Thomas B.

    2009-01-01

    This article describes the successful application of family-based treatment (FBT) for a 17-year-old identical twin presenting with a 4-month history of clinically significant symptoms of anorexia nervosa (AN). FBT is a manualized treatment that has been studied in randomized controlled trials for adolescents with AN. This case study illustrates…

  16. A genetic study on attention problems and academic skills: results of a longitudinal study in twins

    NARCIS (Netherlands)

    Polderman, T.J.C.; Huizink, A.C.; Verhulst, F.C.; van Beijsterveldt, C.E.M.; Boomsma, D.I.; Bartels, M.

    2011-01-01

    Objective Several studies reported a negative association between ADHD symptoms and academic achievement. We investigated the etiology of the association between Attention Problems (AP, one of the core symptoms in ADHD) in early childhood and four academic skills across childhood in a genetically

  17. A note on twin-singleton differences in asthma

    DEFF Research Database (Denmark)

    Thomsen, Simon Francis; Kyvik, Kirsten Ohm; Backer, Vibeke

    2008-01-01

    Twins constitute a valuable resource for genetic studies of asthma. However, critics argue that twins are 'special' in terms of prenatal environment and upbringing and therefore nonrepresentative. In respect to asthma a small range of studies report differential morbidity in twins compared...... with singletons. We review some of the possible explanations for these findings and conclude that results from twin studies of asthma can be extrapolated to the general population....

  18. Physical activity reduces the influence of genetic effects on BMI and waist circumference: a study in young adult twins.

    Science.gov (United States)

    Mustelin, L; Silventoinen, K; Pietiläinen, K; Rissanen, A; Kaprio, J

    2009-01-01

    Both obesity and exercise behavior are influenced by genetic and environmental factors. However, whether obesity and physical inactivity share the same genetic vs environmental etiology has rarely been studied. We therefore analyzed these complex relationships, and also examined whether physical activity modifies the degree of genetic influence on body mass index (BMI) and waist circumference (WC). The FinnTwin16 Study is a population-based, longitudinal study of five consecutive birth cohorts (1975-1979) of Finnish twins. Data on height, weight, WC and physical activity of 4343 subjects at the average age of 25 (range, 22-27 years) years were obtained by a questionnaire and self-measurement of WC. Quantitative genetic analyses based on linear structural equations were carried out by the Mx statistical package. The modifying effect of physical activity on genetic and environmental influences was analyzed using gene-environment interaction models. The overall heritability estimates were 79% in males and 78% in females for BMI, 56 and 71% for WC and 55 and 54% for physical activity, respectively. There was an inverse relationship between physical activity and WC in males (r = -0.12) and females (r=-0.18), and between physical activity and BMI in females (r = -0.12). Physical activity significantly modified the heritability of BMI and WC, with a high level of physical activity decreasing the additive genetic component in BMI and WC. Physically active subjects were leaner than sedentary ones, and physical activity reduced the influence of genetic factors to develop high BMI and WC. This suggests that the individuals at greatest genetic risk for obesity would benefit the most from physical activity.

  19. Neuropsychological effects of irradiation and chemotherapy treatments upon children with acute lymphoblastic leukemia: a case study of monozygotic twins

    International Nuclear Information System (INIS)

    Prince, M.T.; Souheaver, G.T.; Berry, D.H.

    1988-01-01

    Numerous attempts have been made to determine the effects of irradiation and chemotherapy upon cognitive functioning when used for treatment of acute lymphoblastic leukemia (ALL). While many studies