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The present study aimed to determine the genetic and environmental etiology of the association between childhood negative emotionality (NE) and hyperactivity/inattention problems (HIP) using South Korean elementary school twins (mean age = 10.19 years, SD = 1.79 years). Telephone interviews were given to mothers of 919 twins (229 monozygotic males: 112 pairs and 5 individuals; 148 dizygotic males: 73 pairs and 2 individuals; 180 monozygotic females: 87 pairs and 6 individuals; 103 dizygotic females: 50 pairs and 3 individuals; 259 opposite-sex dizygotic twins: 127 pairs and 5 individuals) to assess their children’s NE and HIP. Consistent with prior studies, the phenotypic correlation between NE and the HIP was moderate (r = .29; 95% CI = .24, .34). Model-fitting analysis revealed that additive genetic and nonshared environmental influences on NE were .45 (95% CI [.34, .54]) and .55 (95% CI [.46, .66]), respectively, and that additive and nonadditive genetic, and nonshared environmental influences on HIP were .08 (95% CI [.03, .26]), .41 (95% CI [.21, .51]) and .51 (95% CI = .42, .61), respectively. In addition, the additive genetic correlation between NE and HIP was 1.0 (95% CI [.52, 1.00]), indicating that additive genetic factors are entirely shared between the two phenotypes. Nonadditive genetic influences were unique to HIP and not responsible for the NE-HIP association. Nonshared environmental correlation was significant but modest (re = .18, 95% CI [.06, .30]).

There is a growing body of literature linking religious attendance to prosocial behavior (PB). The main purposes of the present study were to estimate genetic and environmental influences on the frequency of religious attendance (FRA) and to explore whether and how FRA moderates genetic and/or environmental influences on PB. As part of the Nigerian Twin and Sibling Study, 2860 (280 monozygotic male, 417 monozygotic female, 544 dizygotic male, 699 dizygotic female, and 920 opposite-sex dizygotic) twins (mean age = 14.2 years; SD = 1.7 years; age range = 12–18 years) completed a questionnaire regarding FRA and a PB scale. Similar to the findings from western twin samples, FRA showed substantial shared environmental influences of 74% (95% CI = 69%, 78%), with absence of genetic effects. The phenotypic correlation between FRA and PB was modest but positive and significant (r = .12; p < .01), suggesting that PB is higher among more frequent attenders than among less frequent attenders. The results of gene–environment (G × E) interaction model-fitting analysis revealed that FRA changed individual environmental experiences rather than genetic effects on PB such that while genetic variance was stable, non-shared environmental variance declined, leading the total phenotypic variance of PB to decrease with increasing levels of religious attendance.

Kaprio, Jaakko/0000-0002-3716-2455; Huibregtse, Brooke M./0000-0003-0977-7249; Magnusson, Patrik KE/0000-0002-7315-7899; ONCEL, Sevgi YURT/0000-0002-0990-292X; Aliev, Fazil/0000-0001-8357-4699; Silventoinen, Karri/0000-0003-1759-3079; van Beijsterveldt, Toos/0000-0002-6617-4201; Knafo-Noam, Ariel/0000-0003-0613-1960; Latvala, Antti/0000-0001-5695-117X; Loos, Ruth/0000-0002-8532-5087; Bartels, Meike/0000-0002-9667-7555; Sund, Reijo/0000-0002-6268-8117; Willemsen, Gonneke/0000-0003-3755-0236 WOS:000560040700031 PubMed: 32409744 Genetic factors explain a major proportion of human height variation, but differences in mean stature have also been found between socio-economic categories suggesting a possible effect of environment. By utilizing a classical twin design which allows decomposing the variation of height into genetic and environmental components, we tested the hypothesis that environmental variation in height is greater in offspring of lower educated parents. Twin data from 29 cohorts including 65,978 complete twin pairs with information on height at ages 1 to 69 years and on parental education were pooled allowing the analyses at different ages and in three geographic-cultural regions (Europe, North America and Australia, and East Asia). Parental education mostly showed a positive association with offspring height, with significant associations in mid-childhood and from adolescence onwards. In variance decomposition modeling, the genetic and environmental variance components of height did not show a consistent relation to parental education. A random-effects meta-regression analysis of the aggregate-level data showed a trend towards greater shared environmental variation of height in low parental education families. In conclusion, in our very large dataset from twin cohorts around the globe, these results provide only weak evidence for the study hypothesis. Swedish Research Council through the Swedish Initiative for Research on Microdata in the Social And Medical Sciences (SIMSAM) [340-2013-5867]; Stockholm County Council (ALF-projects)Stockholm County Council; Swedish Heart-Lung FoundationSwedish Heart-Lung Foundation; Swedish Asthma and Allergy Association's Research Foundation; Swedish Research CouncilSwedish Research Council [2017-00641]; Netherlands Twin Register acknowledges the Netherlands Organization for Scientific Research (NWO)Netherlands Organization for Scientific Research (NWO) [904-61-090, 985-10-002, 912-10-020, 904-61-193,480-04-004, 463-06-001, 451-04-034, 400-05-717, Addiction-31160008]; European Research CouncilEuropean Research Council (ERC); Avera Institute, Sioux Falls, South Dakota (USA); KNAW Academy Professor Award [PAH/6635]; ENGAGE - European Network for Genetic and Genomic Epidemiology [201413]; National Institute of Alcohol Abuse and AlcoholismUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Alcohol Abuse & Alcoholism (NIAAA) [AA-12502, AA-00145, AA-09203]; Academy of Finland Center of Excellence in Complex Disease GeneticsAcademy of Finland [213506, 129680]; Academy of FinlandAcademy of Finland [100499, 205585, 118555, 141054, 265240, 263278, 308248, 312073, 264146]; Fund of Scientific Research, Flanders and Twins, a non-profit Association for Scientific Research in Multiple Births (Belgium); Cancer Research UKCancer Research UK [C1418/A7974]; European UnionEuropean Union (EU) [HEALTH-F4-2007-201413]; BioSHaRE EU [HEALTH-F4-2010-261433, POCI/DES/56834/2004]; Portuguese agency for research (The Foundation for Science and Technology [FCT]); Krkkale University Research Grant: KKU [2009/43]; TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [114C117]; Osaka University's International Joint Research Promotion Program [R01 HD068435, R01 MH062375]; National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [R21 AG039572]; California Twin Program; California Tobacco-Related Disease Research ProgramUniversity of California System [7RT-0134H, 8RT-0107H, 6RT-0354H]; Carolina African American Twin Study of Aging - National Institute on Aging [1RO1-AG13662-01A2, DA011015, 5T32DA017637, 5T32AG052371]; Michigan State University [R01-MH081813, R01-MH0820-54, R01-MH092377-02, R21-MH070542-01, R03-MH63851-01]; National Institute of Mental Health (NIMH)United States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of Mental Health (NIMH) [R01-HD066040]; Eunice Kennedy Shriver National Institute for Child Health and Human Development (NICHD) [11-SPG-2518]; MSU Foundation - National Institute of Mental Health [R01 MH58354, AA023322, HD081437]; Vietnam Era Twin Study of Aging; National Institute of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [NIA R01 AG018384, R01 AG018386, R01 AG022381, R01 AG022982]; VA San Diego Center of Excellence for Stress and Mental Health; Cooperative Studies Program of the Office of Research & Development of the United States Department of Veterans Affairs; Global Research Network Program of the National Research Foundation [NRF 2011-220-E00006]; National Research Foundation of KoreaNational Research Foundation of Korea [NRF-371-2011-1 B00047]; West Japan Twins and Higher Order Multiple Births Registry [15H05105]; Japan Society for the Promotion of ScienceMinistry of Education, Culture, Sports, Science and Technology, Japan (MEXT)Japan Society for the Promotion of Science; Centre of Research Excellence Grant [1079102]; National Health and Medical Research CouncilNational Health and Medical Research Council of Australia [240994]; [266592] This study was conducted within the CODATwins project (Academy of Finland #266592). The CATSS-Study is supported by the Swedish Research Council through the Swedish Initiative for Research on Microdata in the Social And Medical Sciences (SIMSAM) framework grant no 340-2013-5867, grants provided by the Stockholm County Council (ALF-projects), the Swedish Heart-Lung Foundation and the Swedish Asthma and Allergy Association's Research Foundation. The Swedish Twin Registry is managed by Karolinska Institutet and receives funding through the Swedish Research Council under the grant no 2017-00641. Netherlands Twin Register acknowledges the Netherlands Organization for Scientific Research (NWO) and MagW/ZonMW grants 904-61-090, 985-10-002, 912-10-020, 904-61-193,480-04-004, 463-06-001, 451-04-034, 400-05-717, Addiction-31160008, Middelgroot-911-09-032, Spinozapremie 56-464-14192; Amsterdam Public Health (APH); the European Research Council (ERC - 230374), the Avera Institute, Sioux Falls, South Dakota (USA) and the KNAW Academy Professor Award (PAH/6635) to DIB. Data collection and analyses in Finnish twin cohorts have been supported by ENGAGE - European Network for Genetic and Genomic Epidemiology, FP7-HEALTH-F4-2007, grant agreement number 201413, National Institute of Alcohol Abuse and Alcoholism (grants AA-12502, AA-00145, and AA-09203 to R J Rose, the Academy of Finland Center of Excellence in Complex Disease Genetics (grant numbers: 213506, 129680), and the Academy of Finland (grants 100499, 205585, 118555, 141054, 265240, 263278, 308248, 312073 and 264146 to J Kaprio). Since its origin the East Flanders Prospective Survey has been partly supported by grants from the Fund of Scientific Research, Flanders and Twins, a non-profit Association for Scientific Research in Multiple Births (Belgium). Gemini was supported by a grant from Cancer Research UK (C1418/A7974). Data collection and research stemming from the Norwegian Twin Registry is supported, in part, from the European Union's Seventh Framework Programmes ENGAGE Consortium (grant agreement HEALTH-F4-2007-201413, and BioSHaRE EU (grant agreement HEALTH-F4-2010-261433). Madeira data comes from the following project: Genetic and environmental influences on physical activity, fitness and health: the Madeira family study Project reference: POCI/DES/56834/2004 Founded by the Portuguese agency for research (The Foundation for Science and Technology [FCT]). S.Y. oncel and F. Aliev are supported by Krkkale University Research Grant: KKU, 2009/43 and TUBITAK grant 114C117. K Silventoinen is supported by Osaka University's International Joint Research Promotion Program. The Boston University Twin Project is funded by grants (#R01 HD068435 #R01 MH062375) from the National Institutes of Health to K. Saudino. California Twin Program was supported by The California Tobacco-Related Disease Research Program (7RT-0134H, 8RT-0107H, 6RT-0354H) and the National Institutes of Health (1R01ESO15150-01). The Carolina African American Twin Study of Aging (CAATSA) was funded by a grant from the National Institute on Aging (grant 1RO1-AG13662-01A2) to K. E. Whitfield. Colorado Twin Registry is funded byNIDA funded center grant DA011015, & Longitudinal Twin Study HD10333; Author Huibregtse is supported by 5T32DA017637 and 5T32AG052371.; The Michigan State University Twin Registry has been supported by Michigan State University, as well as grants R01-MH081813, R01-MH0820-54, R01-MH092377-02, R21-MH070542-01, R03-MH63851-01 from the National Institute of Mental Health (NIMH), R01-HD066040 from the Eunice Kennedy Shriver National Institute for Child Health and Human Development (NICHD), and 11-SPG-2518 from the MSU Foundation. The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the official views of the NIMH, the NICHD, or the National Institutes of Health. The University of Southern California Twin Study is funded by a grant from the National Institute of Mental Health (R01 MH58354). The Texas Twin Project is currently funded by grants AA023322 and HD081437 from the National Institutes of Health. Vietnam Era Twin Study of Aging was supported by National Institute of Health grants NIA R01 AG018384, R01 AG018386, R01 AG022381, and R01 AG022982, and, in part, with resources of the VA San Diego Center of Excellence for Stress and Mental Health. The Cooperative Studies Program of the Office of Research & Development of the United States Department of Veterans Affairs has provided financial support for the development and maintenance of the Vietnam Era Twin (VET) Registry. The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the official views of the NIA/NIH, or the VA. The NAS-NRC Twin Registry acknowledges financial support from the National Institutes of Health grant number R21 AG039572. Korean Twin-Family Register was supported by the Global Research Network Program of the National Research Foundation (NRF 2011-220-E00006). South Korea Twin Registry is supported by National Research Foundation of Korea (NRF-371-2011-1 B00047). The West Japan Twins and Higher Order Multiple Births Registry was supported by Grant-in-Aid for Scientific Research (B) (grant number 15H05105) from the Japan Society for the Promotion of Science. This research was facilitated through access to Twins Research Australia, a national resource supported by a Centre of Research Excellence Grant (ID: 1079102), from the National Health and Medical Research Council. Longitudinal Israeli Study of Twins was funded by the Starting Grant no. 240994 from the European Research Council (ERC) to Ariel Knafo.

The South Korean Twin Registry (SKTR) is an ongoing nationwide volunteer registry of South Korean twins and their families. Since its inception, from preschooler to young adult, twins have been registered with the SKTR and have demonstrated that relative influences of genetic and environmental factors explaining individual differences in various psychological, mental health and physical traits in South Koreans are similar to those found in many Western twin studies. Currently, studies at the SKTR focus on identification of the process of gene-by-environment interactions as well as developmental differences in genetic and environmental influences on psychological and mental health traits in South Koreans. This report provides a brief overview, recruitment strategies, current samples, zygosity assessment, measures and future directions of the SKTR.

Here we provide an update of the 2013 report on the Nigerian Twin and Sibling Registry (NTSR). The major aim of the NTSR is to understand genetic and environmental influences and their interplay in psychological and mental health development in Nigerian children and adolescents. Africans have the highest twin birth rates among all human populations, and Nigeria is the most populous country in Africa. Due to its combination of large population and high twin birth rates, Nigeria has one of the largest twin populations in the world. In this article, we provide current updates on the NTSR samples recruited, recruitment procedures, zygosity assessment and findings emerging from the NTSR.

Loos, Ruth J F/0000-0002-8532-5087; Kaprio, Jaakko/0000-0002-3716-2455; Huibregtse, Brooke M./0000-0003-0977-7249; de Freitas, Duarte Luis/0000-0001-6642-3370; Aliev, Fazil/0000-0001-8357-4699; Medda, Emanuela/0000-0003-4837-4549; Bartels, Meike/0000-0002-9667-7555; Latvala, Antti/0000-0001-5695-117X; Sund, Reijo/0000-0002-6268-8117; Rebato, Esther/0000-0003-1221-8501; Silventoinen, Karri/0000-0003-1759-3079; Aaltonen, Sari/0000-0002-2873-4263; Nistico, Lorenza/0000-0003-1805-6240; Knafo-Noam, Ariel/0000-0003-0613-1960; van Beijsterveldt, Toos/0000-0002-6617-4201; Harden, Kathryn/0000-0002-1557-6737; Willemsen, Gonneke/0000-0003-3755-0236; Pahlen, Shandell/0000-0003-0753-4155 WOS: 000465255700021 PubMed: 30950584 Objective The objective of this study was to analyze how parental education modifies the genetic and environmental variances of BMI from infancy to old age in three geographic-cultural regions. Methods A pooled sample of 29 cohorts including 143,499 twin individuals with information on parental education and BMI from age 1 to 79 years (299,201 BMI measures) was analyzed by genetic twin modeling. Results Until 4 years of age, parental education was not consistently associated with BMI. Thereafter, higher parental education level was associated with lower BMI in males and females. Total and additive genetic variances of BMI were smaller in the offspring of highly educated parents than in those whose parents had low education levels. Especially in North American and Australian children, environmental factors shared by co-twins also contributed to the higher BMI variation in the low education level category. In Europe and East Asia, the associations of parental education with mean BMI and BMI variance were weaker than in North America and Australia. Conclusions Lower parental education level is associated with higher mean BMI and larger genetic variance of BMI after early childhood, especially in the obesogenic macro-environment. The interplay among genetic predisposition, childhood social environment, and macro-social context is important for socioeconomic differences in BMI. Collaborative Project of Development of Anthropometrical Measures in Twins (Academy of Finland) [266592]; Swedish Research Council through the Swedish Initiative for Research on Microdata in the Social and Medical Sciences Framework Grant [340-2013-5867]; Stockholm County Council (ALF projects)Stockholm County Council; Swedish Heart-Lung FoundationSwedish Heart-Lung Foundation; Swedish Asthma and Allergy Association's Research Foundation; Netherlands Organization for Scientific ResearchNetherlands Organization for Scientific Research (NWO); MagW/ZonMW [904-61-090, 985-10-002, 912-10-020, 904-61-193, 480-04-004, 463-06-001, 451-04-034, 400-05-717, Addiction-31160008, Middelgroot-911-09-032, Spinozapremie-56-464-14192]; Vrije University's Institute for Health and Care Research; European Research Council (ERC)European Research Council (ERC) [230374]; Avera Institute, Sioux Falls, South Dakota; European Network for Genetic and Genomic Epidemiology (ENGAGE) [FP7-HEALTH-F4-2007, 201413]; National Institute of Alcohol Abuse and AlcoholismUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Alcohol Abuse & Alcoholism (NIAAA) [AA-12502, AA-00145, AA-09203]; Academy of Finland Center of Excellence in Complex Disease GeneticsAcademy of Finland [213506, 129680]; Academy of FinlandAcademy of Finland [100499, 205585, 118555, 141054, 265240, 264146, 312073]; Fund of Scientific Research, FlandersFWO; Twins, a nonprofit Association for Scientific Research in Multiple Births (Belgium); Cancer Research UKCancer Research UK [C1418/A7974]; European Union's Seventh Framework Programmes ENGAGE Consortium [HEALTH-F4-2007-201413]; Biobank Standardization and Harmonization for Research Excellence in the European Union [HEALTH-F4-2010-261433]; Kirikkale UniversityKirikkale University [2009/43]; Scientific and Technological Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [114C117]; Osaka University's International Joint Research Promotion Program; National Institutes of Health (NIH)United States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [R01HD068435, R01MH062375]; California Tobacco-Related Disease Research ProgramUniversity of California System [7RT-0134H, 8RT-0107H, 6RT-0354H]; NIHUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [1R01ESO15150-01, AA023322, HD081437, R21AG039572]; National Institute on Aging (NIA)United States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Aging (NIA) [1R01AG13662-01A2]; National Institute on Drug AbuseUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Drug Abuse (NIDA) [DA011015]; Longitudinal Twin Study grant [HD10333]; MSU; National Institute of Mental Health (NIMH)United States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of Mental Health (NIMH) [R01MH081813, R01MH0820-54, R01MH092377-02, R21MH070542-01, R03MH63851-01]; Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)United States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD) [R01HD066040]; MSU Foundation [11-SPG-2518]; NIMHUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of Mental Health (NIMH) [R01MH58354]; NIH/NIAUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Aging (NIA) [R01AG018384, R01AG018386, R01AG022381, R01AG022982]; VA San Diego Center of Excellence for Stress and Mental Health; Cooperative Studies Program of the Office of Research & Development of the US Department of Veterans Affairs (VA); Global Research Network Program of the National Research Foundation (NRF) [2011-220-E00006]; NRF of Korea [NRF-371-2011-1 B00047]; Japan Society for the Promotion of ScienceMinistry of Education, Culture, Sports, Science and Technology, Japan (MEXT)Japan Society for the Promotion of Science [15H05105]; National Health and Medical Research CouncilNational Health and Medical Research Council of Australia [1079102]; ERCEuropean Research Council (ERC) [240994]; [POCI/DES/56834/2004]; [5T32DA017637]; [5T32AG052371] This study was conducted within the Collaborative Project of Development of Anthropometrical Measures in Twins (Academy of Finland Grant 266592). Funding for individual collaborators is as follows. The Child and Adolescent Twin Study in Sweden is supported by the Swedish Research Council through the Swedish Initiative for Research on Microdata in the Social and Medical Sciences Framework Grant 340-2013-5867, grants provided by the Stockholm County Council (ALF projects), the Swedish Heart-Lung Foundation, and the Swedish Asthma and Allergy Association's Research Foundation. The Netherlands Twin Register acknowledges support from the Netherlands Organization for Scientific Research and MagW/ZonMW Grants 904-61-090, 985-10-002, 912-10-020, 904-61-193,480-04-004, 463-06-001, 451-04-034, 400-05-717, Addiction-31160008, Middelgroot-911-09-032, and Spinozapremie-56-464-14192; Vrije University's Institute for Health and Care Research; the European Research Council (ERC; grant 230374); and the Avera Institute, Sioux Falls, South Dakota. Data collection and analyses in Finnish twin cohorts have been supported by the European Network for Genetic and Genomic Epidemiology (ENGAGE; FP7-HEALTH-F4-2007, grant agreement 201413), the National Institute of Alcohol Abuse and Alcoholism (grants AA-12502, AA-00145, and AA-09203 to R. J. Rose), the Academy of Finland Center of Excellence in Complex Disease Genetics (grants 213506 and 129680), and the Academy of Finland (grants 100499, 205585, 118555, 141054, 265240, 264146, and 312073 to J. Kaprio). Since its origin, the East Flanders Prospective Survey has been partly supported by grants from the Fund of Scientific Research, Flanders and Twins, a nonprofit Association for Scientific Research in Multiple Births (Belgium). Gemini was supported by a grant from Cancer Research UK (C1418/A7974). Data collection and research stemming from the Norwegian Twin Registry are supported, in part, by the European Union's Seventh Framework Programmes ENGAGE Consortium (grant agreement HEALTH-F4-2007-201413) and Biobank Standardization and Harmonization for Research Excellence in the European Union (grant agreement HEALTH-F4-2010-261433). Madeira data come from Genetic and Environmental Influences on Physical Activity, Fitness and Health: the Madeira Family Study (project reference: POCI/DES/56834/2004, founded by the Portuguese agency for research [the Foundation for Science and Technology]). S. Y. Oncel and F. Aliev are supported by a Kirikkale University research grant (2009/43) and a Scientific and Technological Research Council of Turkey grant (114C117). K. Silventoinen is supported by Osaka University's International Joint Research Promotion Program. The Boston University Twin Project is funded by grants (R01HD068435 and R01MH062375) from the National Institutes of Health (NIH) to K. J. Saudino. The California Twin Program was supported by the California Tobacco-Related Disease Research Program (7RT-0134H, 8RT-0107H, and 6RT-0354H) and NIH (1R01ESO15150-01). The Carolina African American Twin Study of Aging was funded by a grant from the National Institute on Aging (NIA; 1R01AG13662-01A2) to K. E. Whitfield. The Colorado Twin Registry is funded by National Institute on Drug Abuse grant DA011015 and Longitudinal Twin Study grant HD10333; B. M. Huibregtse is supported by 5T32DA017637 and 5T32AG052371.; The Michigan State University (MSU) Twin Registry has been supported by MSU, as well as by grants R01MH081813, R01MH0820-54, R01MH092377-02, R21MH070542-01, and R03MH63851-01 from the National Institute of Mental Health (NIMH), grant R01HD066040 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), and grant 11-SPG-2518 from the MSU Foundation. The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the official views of NIMH, NICHD, or NIH. The University of Southern California Twin Study is funded by a grant from NIMH (R01MH58354). The Texas Twin Project is currently funded by grants AA023322 and HD081437 from NIH. The Vietnam Era Twin Study of Aging was supported by NIH/NIA grants R01AG018384, R01AG018386, R01AG022381, and R01AG022982 and, in part, with resources of the VA San Diego Center of Excellence for Stress and Mental Health. The Cooperative Studies Program of the Office of Research & Development of the US Department of Veterans Affairs (VA) has provided financial support for the development and maintenance of the Vietnam Era Twin Registry. The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the official views of NIA/NIH or VA. The National Academy of Sciences-National Research Council Twin Registry acknowledges financial support from NIH grant R21AG039572. The Korean TwinFamily Register was supported by the Global Research Network Program of the National Research Foundation (NRF; 2011-220-E00006). The South Korea Twin Registry is supported by the NRF of Korea (NRF-371-2011-1 B00047). The West Japan Twins and Higher Order Multiple Births Registry was supported by a Grant-inAid for Scientific Research (B) (15H05105) from the Japan Society for the Promotion of Science. This research was facilitated through access to Twins Research Australia, a national resource supported by a Centre of Research Excellence Grant (1079102) from the National Health and Medical Research Council. The Longitudinal Israeli Study of Twins was funded by Starting Grant 240994 from the ERC to A. Knafo-Noam.

Artists and scientists have been the most frequently investigated groups in the literature of creative achievement. We previously found that genetic influences on the artistic and the scientific creative achievement were substantial. Using a self-report measure of creative achievement, the present study estimated the phenotypic relationship between scientific and artistic creative achievements, and investigated shared genetic and environmental sources for the relationship between the two creative achievements. Three hundred and thirty-eight adult Italian twins [79 monozygotic (MZ) pairs & 90 same-sex dizygotic (DZ) pairs] completed the Artistic Creative Achievement (ACA) and the Scientific Creative Achievement (SCA) scales developed from the Creative Achievement Questionnaire. The mean age of the sample was 26.3 years. The phenotypic correlation between the ACA and the SCA was .54. Cross-twin cross-trait correlation was .45 for MZ and .15 for DZ twins. Bivariate Cholesky models were applied to the raw twin data. In the best-fitting model, the genetic and unique environmental correlations between ACA and SCA were .71 and .36, respectively. These results suggest that common sets of genes are largely responsible for the association between ACA and SCA.

Research shows that perceived family cohesion is positively related to prosocial behavior in adolescents. In this study, we investigated heritability of prosocial behavior (PB) and perceived family cohesion (FC) among Nigerian twins attending public schools in Lagos State, Nigeria (mean age = 14.7 years, SD = 1.7 years), and explored the issue of whether children's perception of cohesive family environment moderated genetic and environmental influences on (PB). The PB scale of the Strengths and Difficulties Questionnaire and the FC scale of the Family Adaptability and Cohesion Evaluation Scale III were completed by 2,376 twins (241 monozygotic (MZ) male, 354 MZ female, 440 dizygotic (DZ) male, 553 DZ female, and 788 opposite-sex DZ twins). A general sex-limitation and the bivariate genotype by environment interaction (G×E) models were applied to the data. The general sex-limitation model showed no significant sex differences, indicating that additive genetic and non-shared environmental influences were, 38% (95% CI = 31, 46) and 62% (95% CI = 54, 69) for PB and 33% (95% CI = 24, 40) and 67% (95% CI = 60, 76) for FC in both sexes. These estimates were similar to those found in Western and Asian twin studies to date. The correlation between PB and FC was 0.36. The best-fitting bivariate G×E model indicated that FC significantly moderated non-shared environmental influence unique to PB (E×E interaction). Specifically, non-shared environmental contributions to PB were highest when FC was lowest, and decreased as the levels of FC increased. However, genetic variances in PB were stable across all levels of FC. These findings suggest that FC reduces individual differences in PB by changing non-shared environmental experiences rather than genetic factors in PB.

Sund, Reijo/0000-0002-6268-8117; Heikkila, Kauko/0000-0002-9256-8028; Knafo-Noam, Ariel/0000-0003-0613-1960; Montgomery, Grant W/0000-0002-4140-8139; de Freitas, Duarte Luis/0000-0001-6642-3370; ONCEL, Sevgi YURT/0000-0002-0990-292X; Fagnani, Corrado/0000-0001-5771-7772; Loos, Ruth J F/0000-0002-8532-5087; Kaprio, Jaakko/0000-0002-3716-2455; Huibregtse, Brooke M./0000-0003-0977-7249; ROMERA, JUAN FRANCISCO SANCHEZ/0000-0002-5405-6216; Colodro-Conde, Lucia/0000-0002-9004-364X; Tan, Qihua/0000-0003-3194-0030; Ordonana, Juan R./0000-0001-7779-6017; Kandler, Christian/0000-0002-9175-235X; Aliev, Fazil/0000-0001-8357-4699; Siribaddana, Sisira/0000-0001-5821-2557; Busjahn, Andreas/0000-0001-9650-6919; Tan, Qihua/0000-0003-3194-0030; Rasmussen, Finn/0000-0001-7915-7809; Silventoinen, Karri/0000-0003-1759-3079; Pedersen, Nancy/0000-0001-8057-3543; van Beijsterveldt, Toos/0000-0002-6617-4201; Franz, Carol/0000-0002-8987-1755; Rebato, Esther/0000-0003-1221-8501; Pahlen, Shandell/0000-0003-0753-4155; Harden, Kathryn/0000-0002-1557-6737; Bartels, Meike/0000-0002-9667-7555; Willemsen, Gonneke/0000-0003-3755-0236; Latvala, Antti/0000-0001-5695-117X WOS: 000412597600005 PubMed: 28975875 Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller in more recent birth cohorts for both males and females. Parental education was somewhat longer for fathers of DZ twins in cohorts born in 1990-1999 (0.16 years, 95% CI [0.08, 0.25]) and 2000 or later (0.11 years, 95% CI [0.00, 0.22]), compared with fathers of MZ twins. The results show that the years of both individual and parental education are largely similar in MZ and DZ twins. We suggest that the socio-economic differences between MZ and DZ twins are so small that inferences based upon genetic modeling of twin data are not affected. CODATwins project (Academy of Finland) [266592]; National Health and Medical Research CouncilNational Health and Medical Research Council of Australia [1079102]; National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [R01 HD068435, R01 MH062375, 1R01ESO15150-01, R21 AG039572, AA023322, HD081437, NIA R01 AG018384, R01 AG018386, R01 AG022381, R01 AG022982]; California Tobacco-Related Disease Research ProgramUniversity of California System [7RT-0134H, 8RT-0107H, 6RT-0354H]; National Institute on AgingUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Aging (NIA) [1RO1-AG13662-01A2]; Swedish Research Council through the Swedish Initiative for Research on Microdata in the Social And Medical Sciences (SIMSAM) [340-2013-5867]; Stockholm County Council (ALF)Stockholm County Council; Swedish Heart-Lung FoundationSwedish Heart-Lung Foundation; Swedish Asthma and Allergy Association's Research Foundation; NIDAUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Drug Abuse (NIDA) [DA011015]; Longitudinal Twin Study [HD10333]; Fund of Scientific Research, Flanders and Twins; ENGAGE European Network for Genetic and Genomic Epidemiology [201413]; National Institute of Alcohol Abuse and AlcoholismUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Alcohol Abuse & Alcoholism (NIAAA) [AA-12502, AA-00145, AA-09203]; Academy of Finland Center of Excellence in Complex Disease GeneticsAcademy of Finland [213506, 129680]; Academy of FinlandAcademy of Finland [100499, 205585, 118555, 141054, 265240, 263278, 264146]; Cancer Research UKCancer Research UK [C1418/A7974]; Medexpert Ltd., Budapest, Hungary; Global Research Network Program of the National Research Foundation [NRF 2011-220-E00006]; European Research Council (ERC)European Research Council (ERC) [240994]; Michigan State University; National Institute of Mental Health (NIMH)United States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of Mental Health (NIMH) [R01-MH081813, R01-MH0820-54, R01-MH092377-02, R21-MH070542-01, R03-MH63851-01]; Eunice Kennedy Shriver National Institute for Child Health and Human Development (NICHD) [R01-HD066040]; MSU Foundation [11-SPG-2518]; Fundacion SenecaFundacion Seneca; Regional Agency for Science and Technology, Murcia, Spain [08633/PHCS/08, 15302/PHCS/10, 19479/PI/14]; Ministry of Science and Innovation, SpainSpanish Government [PSI2009-11560, PSI2014-56680-R]; MagW/ZonMW [904-61-090, 985-10-002, 912-10-020, 904-61-193, 480-04-004, 463-06-001, 451-04-034, 400-05-717, Addiction-31160008, Middelgroot-911-09-032, Spinozapremie 56-464-14192]; VU University's Institute for Health and Care Research (EMGO+); European Research CouncilEuropean Research Council (ERC) [ERC - 230374]; Avera Institute, Sioux Falls, South Dakota (USA); National Research Foundation of KoreaNational Research Foundation of Korea [NRF-371-2011-1 B00047]; Krkkale University Research Grant [2009/43]; TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [114C117]; Cooperative Studies Program of the Office of Research AMP; Development of the United States Department of Veterans Affairs; Japan Society for the Promotion of ScienceMinistry of Education, Culture, Sports, Science and Technology, Japan (MEXT)Japan Society for the Promotion of Science [15H05105]; National Institute of Mental HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of Mental Health (NIMH) [R01 MH58354]; JSPS KAKENHI JP [23593419, 24792601, 26671010, 24590695, 26293128, 16K15385, 16K15978, 16K15989, 16H03261]; [5T32DA017637-11]; [POCI/DES/56834/2004]; [NIH RC2 HL103416] This study was conducted within the CODATwins project (Academy of Finland #266592). The Australian Twin Registry is supported by a Centre of Research Excellence (grant ID 1079102) from the National Health and Medical Research Council administered by the University of Melbourne. The Boston University Twin Project is funded by grants (#R01 HD068435 #R01 MH062375) from the National Institutes of Health to K. Saudino. California Twin Program was supported by The California Tobacco-Related Disease Research Program (7RT-0134H, 8RT-0107H, 6RT-0354H) and the National Institutes of Health (1R01ESO15150-01). The Carolina African American Twin Study of Aging (CAATSA) was funded by a grant from the National Institute on Aging (grant 1RO1-AG13662-01A2) to K. E. Whitfield. The CATSS-Study is supported by the Swedish Research Council through the Swedish Initiative for Research on Microdata in the Social And Medical Sciences (SIMSAM) framework grant no 340-2013-5867, grants provided by the Stockholm County Council (ALF-projects), the Swedish Heart-Lung Foundation and the Swedish Asthma and Allergy Association's Research Foundation. Colorado Twin Registry is funded by NIDA funded center grant DA011015 and Longitudinal Twin Study HD10333; Author Huibregtse is supported by 5T32DA017637-11. Since its origin, the East Flanders Prospective Survey has been partly supported by grants from the Fund of Scientific Research, Flanders and Twins, a non-profit Association for Scientific Research in Multiple Births (Belgium). Data collection and analyses in Finnish twin cohorts have been supported by ENGAGE European Network for Genetic and Genomic Epidemiology, FP7-HEALTH-F4-2007, grant agreement number 201413, National Institute of Alcohol Abuse and Alcoholism (grants AA-12502, AA-00145, and AA-09203 to R J Rose, the Academy of Finland Center of Excellence in Complex Disease Genetics (grant numbers: 213506, 129680), and the Academy of Finland (grants 100499, 205585, 118555, 141054, 265240, 263278, and 264146 to J Kaprio). Gemini was supported by a grant from Cancer Research UK (C1418/A7974). Anthropometric measurements of the Hungarian twins were supported by Medexpert Ltd., Budapest, Hungary. Korean Twin-Family Register was supported by the Global Research Network Program of the National Research Foundation (NRF 2011-220-E00006). Longitudinal Israeli Study of Twins was funded by the Starting Grant no. 240994 from the European Research Council (ERC) to Ariel Knafo. The Michigan State University Twin Registry has been supported by Michigan State University, as well as grants R01-MH081813, R01-MH0820-54, R01-MH092377-02, R21-MH070542-01, R03-MH63851-01 from the National Institute of Mental Health (NIMH), R01-HD066040 from the Eunice Kennedy Shriver National Institute for Child Health and Human Development (NICHD), and 11-SPG-2518 from the MSU Foundation. The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the official views of the NIMH, the NICHD, or the National Institutes of Health. The Murcia Twin Registry is supported by Fundacion Seneca, Regional Agency for Science and Technology, Murcia, Spain (08633/PHCS/08, 15302/PHCS/10 & 19479/PI/14) and Ministry of Science and Innovation, Spain (PSI2009-11560 & PSI2014-56680-R). The NAS-NRC Twin Registry acknowledges financial support from the National Institutes of Health grant number R21 AG039572.; r Netherlands Twin Register acknowledges the Netherlands Organization for Scientific Research (NWO) and MagW/ZonMW grants 904-61-090, 985-10-002, 912-10-020, 904-61-193,480-04-004, 463-06-001, 451-04-034, 400-05-717, Addiction-31160008, Middelgroot-911-09-032, Spinozapremie 56-464-14192; VU University's Institute for Health and Care Research (EMGO+); the European Research Council (ERC - 230374), the Avera Institute, Sioux Falls, South Dakota (USA). Madeira data comes from the following project: Genetic and environmental influences on physical activity, fitness, and health: the Madeira family study. Project reference: POCI/DES/56834/2004. Founded by the Portuguese agency for research (The Foundation for Science and Technology [FCT]). South Korea Twin Registry is supported by National Research Foundation of Korea (NRF-371-2011-1 B00047). The Texas Twin Project is currently funded by grants AA023322 and HD081437 from the National Institutes of Health. S. Y. oncel and F. Aliev are supported by Krkkale University Research Grant: KKU, 2009/43 and TUBITAK grant 114C117. Washington State Twin Registry (formerly the University of Washington Twin Registry) was supported in part by grant NIH RC2 HL103416 (D. Buchwald, PI). Vietnam Era Twin Study of Aging was supported by National Institute of Health grants NIA R01 AG018384, R01 AG018386, R01 AG022381, and R01 AG022982, and, in part, with resources of the VA San Diego Center of Excellence for Stress and Mental Health. The Cooperative Studies Program of the Office of Research & Development of the United States Department of Veterans Affairs has provided financial support for the development and maintenance of the Vietnam Era Twin (VET) Registry. The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the official views of the NIA/NIH, or the VA. The West Japan Twins and Higher Order Multiple Births Registry was supported by Grant-in-Aid for Scientific Research (B) (grant number 15H05105) from the Japan Society for the Promotion of Science. The University of Southern California Twin Study is funded by a grant from the National Institute of Mental Health (R01 MH58354). Osaka University Aged Twin Registry is supported by grants from JSPS KAKENHI JP (23593419, 24792601, 26671010, 24590695, 26293128, 16K15385, 16K15978, 16K15989, 16H03261).

Sample size, mean, standard deviation and range for age by cohort in females from same- and opposite-sex dizygotic twin pairs. Table S2. Sample size, mean, standard deviation, and range for age by cohort in males from same- and opposite-sex dizygotic twin pairs. Table S3. Sample size, mean, and standard deviation for height (cm) and BMI (kg/m2) by cohort in females from same- and opposite-sex dizygotic twin pairs. Table S4. Sample size, mean, and standard deviation for height (cm) and BMI (kg/m2) by cohort in males from same- and opposite-sex dizygotic twin pairs. (DOCX 45 kb)

Heikkila, Kauko/0000-0002-9256-8028; McAdams, Tom/0000-0002-6825-3499; Ordonana, Juan R./0000-0001-7779-6017; Siribaddana, Sisira/0000-0001-5821-2557; Tan, Qihua/0000-0003-3194-0030; Skytthe, Axel E/0000-0002-8629-4913; Hjelmborg, Jacob/0000-0001-9630-9149; Kaprio, Jaakko/0000-0002-3716-2455; Loos, Ruth J F/0000-0002-8532-5087; ONCEL, Sevgi YURT/0000-0002-0990-292X; Fagnani, Corrado/0000-0001-5771-7772; mangino, massimo/0000-0002-2167-7470; Colodro-Conde, Lucia/0000-0002-9004-364X; Kandler, Christian/0000-0002-9175-235X; ROMERA, JUAN FRANCISCO SANCHEZ/0000-0002-5405-6216; Montgomery, Grant W/0000-0002-4140-8139; Medland, Sarah E/0000-0003-1382-380X; Christensen, Kaare/0000-0002-5429-5292; Aliev, Fazil/0000-0001-8357-4699; Huibregtse, Brooke M./0000-0003-0977-7249; Busjahn, Andreas/0000-0001-9650-6919; Tan, Qihua/0000-0003-3194-0030; Sund, Reijo/0000-0002-6268-8117; Kremen, William/0000-0002-8629-5609; Pahlen, Shandell/0000-0003-0753-4155; Rasmussen, Finn/0000-0001-7915-7809; Franz, Carol/0000-0002-8987-1755; Pedersen, Nancy/0000-0001-8057-3543; Aaltonen, Sari/0000-0002-2873-4263; Hotopf, Matthew/0000-0002-3980-4466; Rebato, Esther/0000-0003-1221-8501; Kyvik, Kirsten Ohm/0000-0003-2981-0245; Rijsdijk, Fruhling/0000-0003-4762-2803; Silventoinen, Karri/0000-0003-1759-3079 WOS: 000391277600001 PubMed: 27964777 Human height variation is determined by genetic and environmental factors, but it remains unclear whether their influences differ across birth-year cohorts. We conducted an individual-based pooled analysis of 40 twin cohorts including 143,390 complete twin pairs born 18861994. Although genetic variance showed a generally increasing trend across the birth-year cohorts, heritability estimates (0.69-0.84 in men and 0.53-0.78 in women) did not present any clear pattern of secular changes. Comparing geographic-cultural regions (Europe, North America and Australia, and East Asia), total height variance was greatest in North America and Australia and lowest in East Asia, but no clear pattern in the heritability estimates across the birth-year cohorts emerged. Our findings do not support the hypothesis that heritability of height is lower in populations with low living standards than in affluent populations, nor that heritability of height will increase within a population as living standards improve. Suomen Akatemia [266592] Suomen Akatemia 266592 Karri Silventoinenr The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

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.

The prevalence of the feeling of cold hands and feet (FCHF) is high in the general population but the etiology of FCHF is largely unknown. The aim of the present study was to explore whether the FCHF is heritable. Eight hundred and ninety-four pairs of twins completed a question about FCHF. Tetrachoric correlations for FCHF were .58, .29, .67, .52, and .04 for monozygotic male, dizygotic male, monozygotic female, and dizygotic female twins, respectively. Model-fitting analyses suggested that in the best fitting model, additive genetic and nonshared environmental variance including measurement error were 64% (95% CI: 55%-72%) and 36% (28%-45%), respectively. Sex differences in genetic and environmental influences were not significant.

Despite numerous folk sayings about miserly people, the genetic and environmental architecture of the character trait of miserliness has been very rarely studied to date. We administered six items of the miserliness scale to 1110 pairs of South Korean twins aged 12- to 25-years (M = 18.0, SD = 3.3). Model-fitting analyses indicated that 28% (95% CI: 21–34%) and 72% (95% CI: 66–79%) of individual difference in miserliness were attributable to genetic and unique environmental influences, respectively. Common family environmental effects were negligible, consistent with a large body of behavioral genetic literature on personality. Sex differences in the magnitude of genetic and environmental factors in miserliness were not significant.

McAdams, Tom/0000-0002-6825-3499; Skytthe, Axel E/0000-0002-8629-4913; Kandler, Christian/0000-0002-9175-235X; Siribaddana, Sisira/0000-0001-5821-2557; Tan, Qihua/0000-0003-3194-0030; Huibregtse, Brooke M./0000-0003-0977-7249; Fagnani, Corrado/0000-0001-5771-7772; Montgomery, Grant W/0000-0002-4140-8139; Kaprio, Jaakko/0000-0002-3716-2455; Hjelmborg, Jacob/0000-0001-9630-9149; Medland, Sarah E/0000-0003-1382-380X; Christensen, Kaare/0000-0002-5429-5292; Tan, Qihua/0000-0003-3194-0030; Ahrenfeldt, Linda/0000-0002-5018-1642; Ordonana, Juan R./0000-0001-7779-6017; Loos, Ruth J F/0000-0002-8532-5087; Magnusson, Patrik/0000-0002-7315-7899; Aliev, Fazil/0000-0001-8357-4699; Busjahn, Andreas/0000-0001-9650-6919; Colodro-Conde, Lucia/0000-0002-9004-364X; ROMERA, JUAN FRANCISCO SANCHEZ/0000-0002-5405-6216; ONCEL, Sevgi YURT/0000-0002-0990-292X; Rebato, Esther/0000-0003-1221-8501; Pedersen, Nancy/0000-0001-8057-3543; Pietilainen, Kirsi/0000-0002-8522-1288; van Beijsterveldt, Toos/0000-0002-6617-4201; Willemsen, Gonneke/0000-0003-3755-0236; Bartels, Meike/0000-0002-9667-7555; Kyvik, Kirsten Ohm/0000-0003-2981-0245; Vuoksimaa, Eero/0000-0002-6534-3667; Pahlen, Shandell/0000-0003-0753-4155; Silventoinen, Karri/0000-0003-1759-3079 WOS: 000400473600001 PubMed: 28465822 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 prevalence of being overweight or obese between men and women from OS and SS dizygotic twin pairs. Methods: 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. Results: 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. Conclusions: 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. Centre of Research Excellence from the National Health and Medical Research CouncilNational Health and Medical Research Council of Australia [1079102]; California Tobacco-Related Disease Research ProgramUniversity of California System [7RT-0134H, 8RT-0107H, 6RT-0354H]; National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [1R01ESO15150-01]; National Institute on AgingUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Aging (NIA) [1RO1-AG13662-01A2]; NIDAUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Drug Abuse (NIDA) [DA011015]; Longitudinal Twin Study [HD10333]; National Program for Research Infrastructure from the Danish Agency for Science, Technology and Innovation; Research Council for Health and Disease; Velux Foundation; US National Institute of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [P01 AG08761]; MagW/ZonMW [04-61-090, 985-10-002, 912-10-020, 904-61-193, 480-04-004, 463-06-001, 451-04-034, 400-05-717, Addiction-31160008, Middelgroot-911-09-032, Spinozapremie 56-464-14192]; VU University's Institute for Health and Care Research (EMGO+); European Research CouncilEuropean Research Council (ERC) [ERC-230374]; Avera Institute; Sioux Falls; South Dakota (USA); National Institute of Alcohol Abuse and AlcoholismUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Alcohol Abuse & Alcoholism (NIAAA) [AA-12502, AA-00145, AA-09203]; Academy of Finland Center of Excellence in Complex Disease GeneticsAcademy of Finland [213506, 129680]; Academy of FinlandAcademy of Finland [100499, 205585, 118555, 141054, 265240, 263278, 264146]; Osaka University's International Joint Research Promotion Program; Fund of Scientific Research, Flanders and Twins; W T Grant Foundation; University of London Central Research fund; Medical Research Council Training FellowshipMedical Research Council UK (MRC) [G81/343]; Career Development Award [G120/635]; Economic and Social Research CouncilEconomic & Social Research Council (ESRC) [RES-00022-2206]; Institute of Social Psychiatry [06/07-11]; Leverhulme Research FellowshipLeverhulme Trust [RF/2/RFG/2008/0145]; Goldsmiths, University of London; Medexpert Ltd., Budapest, Hungary; Fundacion Seneca, Regional Agency for Science and Technology, Murcia, Spain [08633/PHCS/08, 15302/PHCS/10, 19479/PI/14]; Ministry of Science and Innovation SpainSpanish Government [PSI2009-11560, PSI2014-56680-R]; National Institute of Mental HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of Mental Health (NIMH) [R01 MH58354]; National Research Foundation of KoreaNational Research Foundation of Korea [NRF-371-2011-1 B0004/]; Kirikkale University, KKUKirikkale University [2009/43]; TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [114C117]; Washington State Twin Registry [NIH RC2 HL103416]; Japan Society for the Promotion of ScienceMinistry of Education, Culture, Sports, Science and Technology, Japan (MEXT)Japan Society for the Promotion of Science [15H05105]; ENGAGE-European Network for Genetic and Genomic Epidemiology [201413]; [5T32DA01/63/-11]; Novo Nordisk FondenNovo NordiskNovo Nordisk Foundation [NNF10CC1016515] This study was conducted within the CODATwins project (Academy of Finland #266592). The lead author wishes to thank the Juho Vainio Foundation and the Yrjo Jahnsson Foundation. The Australian Twin Registry is supported by a Centre of Research Excellence (grant ID 1079102) from the National Health and Medical Research Council administered by the University of Melbourne. California Twin Program was supported by The California Tobacco-Related Disease Research Program (7RT-0134H, 8RT-0107H, 6RT-0354H) and the National Institutes of Health (1R01ESO15150-01). The Carolina African American Twin Study of Aging (CAATSA) was funded by a grant from the National Institute on Aging (grant 1RO1-AG13662-01A2) to K.E. Whitfield. Colorado Twin Registry is funded by NIDA funded center grant DA011015, and Longitudinal Twin Study HD10333; Author Huibregtse is supported by 5T32DA01/63/-11. Danish Twin Registry is supported by the National Program for Research Infrastructure 2007 from the Danish Agency for Science, Technology and Innovation, The Research Council for Health and Disease, the Velux Foundation, and the US National Institute of Health (P01 AG08761). Netherlands Twin Register acknowledges the Netherlands Organization for Scientific Research (NWO) and MagW/ZonMW grants 904-61-090, 985-10-002, 912-10-020, 904-61-193,480-04-004, 463-06-001, 451-04-034, 400-05-717, Addiction-31160008, Middelgroot-911-09-032, and Spinozapremie 56-464-14192; VU University's Institute for Health and Care Research (EMGO+); and the European Research Council (ERC-230374), the Avera Institute, Sioux Falls, South Dakota (USA). Data collection and analyses in Finnish twin cohorts have been supported by ENGAGE-European Network for Genetic and Genomic Epidemiology, FP7-HEALTH-F4-2007, grant agreement number 201413, National Institute of Alcohol Abuse and Alcoholism (grants AA-12502, AA-00145, and AA-09203) to R J Rose, the Academy of Finland Center of Excellence in Complex Disease Genetics (grant numbers: 213506, 129680), and the Academy of Finland (grants 100499, 205585, 118555, 141054, 265240, 263278 and 264146 to J Kaprio). K Silventoinen is supported by Osaka University's International Joint Research Promotion Program. Since its origin the East Flanders Prospective Survey has been partly supported by grants from the Fund of Scientific Research, Flanders and Twins, a non-profit Association for Scientific Research in Multiple Births (Belgium). Waves 1-3 of Genesis 12-19 were funded by the W T Grant Foundation, the University of London Central Research fund and a Medical Research Council Training Fellowship (G81/343) and Career Development Award (G120/635) to Thalia C. Eley. Wave 4 was supported by grants from the Economic and Social Research Council (RES-00022-2206) and the Institute of Social Psychiatry (06/07-11) to Alice M. Gregory who was also supported at that time by a Leverhulme Research Fellowship (RF/2/RFG/2008/0145). Wave 5 was supported by funding to Alice M. Gregory from Goldsmiths, University of London. Anthropometric measurements of the Hungarian twins were supported by Medexpert Ltd., Budapest, Hungary. The Murcia Twin Registry is supported by Fundacion Seneca, Regional Agency for Science and Technology, Murcia, Spain (08633/PHCS/08, 15302/PHCS/10 & 19479/PI/14) and Ministry of Science and Innovation Spain (PSI2009-11560 & PSI2014-56680-R). The University of Southern California Twin Study is funded by a grant from the National Institute of Mental Health (R01 MH58354).; South Korea Twin Registry is supported by National Research Foundation of Korea (NRF-371-2011-1 B0004/). S.Y. Oncel and F. Aliev are supported by Kirikkale University Research Grant: KKU, 2009/43 and TUBITAK grant 114C117. Washington State Twin Registry (formerly the University of Washington Twin Registry) was supported in part by grant NIH RC2 HL103416 (D. Buchwald,PI). The West Japan Twins and Higher Order Multiple Births Registry was supported by Grant-in-Aid for Scientific Research (B) (grant number 15H05105) from the Japan Society for the Promotion of Science.

The South Korean Twin Registry (SKTR) is an ongoing nation-wide volunteer registry of South Korean twins and their families, which was established in the year 2001 to understand genetic and environmental etiologies of psychological and physical traits among South Koreans. Recently, the SKTR sampling has been extended in two important ways. First, we began to recruit twins from lower socio-economic families to study interaction effects of gene by environmental context. Second, as a parallel study of the SKTR, the Nigerian Twin and Sibling Registry was developed to understand the origin of the population group differences/similarities in psychological traits between South Koreans and Nigerians. This article summarizes the main findings (based on the SKTR sample to date), recruitment procedures, zygosity assessment, measures, and future plans for the SKTR.

Twin studies of Africans have been scarce although Africans have shown the highest twin birth rate in the world. As a parallel study of the South Korean Twin Registry, the Nigerian Twin and Sibling Registry (NTSR) was developed to understand causal influences on the development of cognitive abilities, personality, and mental health among Nigerians. Currently, 1,134 twins and 404 full- and half-siblings have been registered with NTSR. This article describes research background, goals, major recruitment strategies, measures, and future directions of the NTSR.

The mothers of 603 pairs of 3- to 13-year-old twins in Korea completed the Emotionality, Activity, Sociability (EAS) Temperament Survey and the Strengths and Difficulties Questionnaire in reference to their twins. Principal factor analysis of the seven scales comprising these measures yielded a general factor on which all the scales had moderate to large loadings. Univariate behavioral genetic analyses showed that individual differences on this general factor could best be accounted for by additive genetic and non-shared environmental effects, with a heritability of 53%. The results strengthen the construct validity of the general factor of personality (GFP) by extracting this higher-order dimension from disparate measures, and have implications regarding social desirability criticisms applied to the GFP theory.

Recent molecular genetic studies provide suggestive evidence for sexual dimorphism in genetics of obsessive-compulsive disorder. However, only a few twin studies have addressed the question of sex differences in genetic and environmental contributions to variation of obsessive–compulsive symptoms. The aim of the present study was to estimate genetic and environmental influences on obsessive–compulsive symptoms in South Korean twins, with a special emphasis on sex difference. In total, 751 adolescent and young adult twin pairs (ages: 13–23 years) completed a Korean version of the 30 items of the Maudsley Obsessional — Compulsive Inventory (MOCI) through a mail survey. A sum of the answers for the 30 items was calculated to represent a total score for obsessive–compulsive symptoms (hereafter, the MOCIT). Males had significantly higher variance of the MOCIT than did females. In males, monozygotic (MZ) twin correlation was significantly higher than dizygotic (DZ) twin correlations (.56 vs. .24), whereas in females, MZ and DZ twin correlations were not significantly different from each other (.39 vs. .36). The general sex-limitation model was applied to the twin data. The results of model-fitting analyses indicated that the unstandardized genetic variance as well as heritability estimate (53% vs. 41%) for the MOCIT was higher in males than in females. However, shared environmental influences did not attain statistical significance perhaps due to insufficient statistical power.

The South Korean Twin Registry (SKTR), previously called the Seoul Twin Family Study, is a nationwide volunteer registry of South Korean twins and their families. Since 2002, the SKTR has been updated in 4 important ways. First, continued sampling led to an increase in the number of twins. Second, the target area, Seoul, was enlarged to include other cities and rural areas in the country. Third, the target population was extended from school-aged twins to preschool and adult twins. Fourth, the research focus was expanded to include psychiatric and physical disease phenotypes. The present article describes a brief history of the SKTR, goals and current research highlights, recent major accomplishments, and future directions.

Magnusson, Patrik/0000-0002-7315-7899; Christensen, Kaare/0000-0002-5429-5292; Montgomery, Grant W/0000-0002-4140-8139; Fagnani, Corrado/0000-0001-5771-7772; ROMERA, JUAN FRANCISCO SANCHEZ/0000-0002-5405-6216; Siribaddana, Sisira/0000-0001-5821-2557; Tan, Qihua/0000-0003-3194-0030; Busjahn, Andreas/0000-0001-9650-6919; Tan, Qihua/0000-0003-3194-0030; Ordonana, Juan R./0000-0001-7779-6017; Sund, Reijo/0000-0002-6268-8117; Hjelmborg, Jacob/0000-0001-9630-9149; ONCEL, Sevgi YURT/0000-0002-0990-292X; Colodro-Conde, Lucia/0000-0002-9004-364X; Kandler, Christian/0000-0002-9175-235X; McAdams, Tom/0000-0002-6825-3499; mangino, massimo/0000-0002-2167-7470; Huibregtse, Brooke M./0000-0003-0977-7249; Aliev, Fazil/0000-0001-8357-4699; Kaprio, Jaakko/0000-0002-3716-2455; Skytthe, Axel E/0000-0002-8629-4913; Loos, Ruth J F/0000-0002-8532-5087; Pietilainen, Kirsi/0000-0002-8522-1288; Aaltonen, Sari/0000-0002-2873-4263; Pahlen, Shandell/0000-0003-0753-4155; Rasmussen, Finn/0000-0001-7915-7809; van Beijsterveldt, Toos/0000-0002-6617-4201; Franz, Carol/0000-0002-8987-1755; Bartels, Meike/0000-0002-9667-7555; Kyvik, Kirsten Ohm/0000-0003-2981-0245; Willemsen, Gonneke/0000-0003-3755-0236; Pedersen, Nancy/0000-0001-8057-3543; Silventoinen, Karri/0000-0003-1759-3079 WOS: 000406672300007 PubMed: 28679550 Background: Genes and the environment contribute to variation in adult body mass index [BMI (in kg/m(2))], but factors modifying these variance components are poorly understood. Objective: We analyzed genetic and environmental variation in BMI between men and women from young adulthood to old age from the 1940s to the 2000s and between cultural-geographic regions representing high (North America and Australia), moderate (Europe), and low (East Asia) prevalence of obesity. Design: We used genetic structural equation modeling to analyze BMI in twins >= 20 y of age from 40 cohorts representing 20 countries (140,379 complete twin pairs). Results: The heritability of BMI decreased from 0.77 (95% CI: 0.77, 0.78) and 0.75 (95% CI: 0.74, 0.75) in men and women 2029 y of age to 0.57 (95% CI: 0.54, 0.60) and 0.59 (95% CI: 0.53, 0.65) in men 70-79 y of age and women 80 y of age, respectively. The relative influence of unique environmental factors correspondingly increased. Differences in the sets of genes affecting BMI in men and women increased from 20-29 to 60-69 y of age. Mean BMI and variances in BMI increased from the 1940s to the 2000s and were greatest in North America and Australia, followed by Europe and East Asia. However, heritability estimates were largely similar over measurement years and between regions. There was no evidence of environmental factors shared by co-twins affecting BMI. Conclusions: The heritability of BMI decreased and differences in the sets of genes affecting BMI in men and women increased from young adulthood to old age. The heritability of BMI was largely similar between cultural-geographic regions and measurement years, despite large differences in mean BMI and variances in BMI. Our results show a strong influence of genetic factors on BMI, especially in early adulthood, regardless of the obesity level in the population. Medical Research CouncilMedical Research Council UK (MRC) [G120/635]; NIA NIH HHSUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Aging (NIA) [P30 AG017265, R01 AG018384]; NIDA NIH HHSUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute on Drug Abuse (NIDA) [T32 DA017637]; NIDDK NIH HHSUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of Diabetes & Digestive & Kidney Diseases (NIDDK) [P30 DK020541]

The differences in height (cm) between opposite sex (OS) and same sex (SS) plotted against the mean heights (cm) of the cohorts for females and males. The figure examines whether the difference in height between OS and SS twins is greater in taller cohorts. The Spearman correlations are r = −0.16 and p = 0.39 for females and r = 0.10 and p = 0.59 for males. Figure S2. The differences in BMI (kg/m2) between opposite-sex (OS) and same-sex (SS) twins plotted against the mean BMIs (kg/m2) of the cohorts for females and males. The figure examines whether the difference in BMI between OS and SS twins is greater in heavier cohorts. The Spearman correlations are r = −0.39 and p = 0.029 in females and r = 0.10 and p = 0.61 for BMI in males. (DOCX 159 kb)

The differences in height (cm) between opposite sex (OS) and same sex (SS) plotted against the mean heights (cm) of the cohorts for females and males. The figure examines whether the difference in height between OS and SS twins is greater in taller cohorts. The Spearman correlations are r = −0.16 and p = 0.39 for females and r = 0.10 and p = 0.59 for males. Figure S2. The differences in BMI (kg/m2) between opposite-sex (OS) and same-sex (SS) twins plotted against the mean BMIs (kg/m2) of the cohorts for females and males. The figure examines whether the difference in BMI between OS and SS twins is greater in heavier cohorts. The Spearman correlations are r = −0.39 and p = 0.029 in females and r = 0.10 and p = 0.61 for BMI in males. (DOCX 159 kb)