The CODATwins Project: The Cohort Description of Collaborative Project of Development of Anthropometrical Measures in Twins to Study Macro-Environmental Variation in Genetic and Environmental Effects on Anthropometric Traits
Authors: Silventoinen Karri , Jelenkovic Aline , Sund Reijo , Honda Chika , Aaltonen Sari , Yokoyama Yoshie , Tarnoki Adam D. , Tarnoki David L. , Ning Feng , Ji Fuling , 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 , 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 , 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. , Christensen Kaare , Skytthe Axel , Kyvik Kirsten O. , Hong Changhee , Chong Youngsook , 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 , Rasmussen Finn , Sung Joohon , Harris Jennifer R. , Willemsen Gonneke , Busjahn Andreas , Goldberg Jack H. , Boomsma Dorret I. , Hur Yoon-Mi , Sørensen Thorkild I. A. , Kaprio Jaakko 
Published: May 2015

For over 100 years, the genetics of human anthropometric traits has attracted scientific interest. In particular, height and body mass index (BMI, calculated as kg/m2) have been under intensive genetic research. However, it is still largely unknown whether and how heritability estimates vary between human populations. Opportunities to address this question have increased recently because of the establishment of many new twin cohorts and the increasing accumulation of data in established twin cohorts. We started a new research project to analyze systematically (1) the variation of heritability estimates of height, BMI and their trajectories over the life course between birth cohorts, ethnicities and countries, and (2) to study the effects of birth-related factors, education and smoking on these anthropometric traits and whether these effects vary between twin cohorts. We identified 67 twin projects, including both monozygotic (MZ) and dizygotic (DZ) twins, using various sources. We asked for individual level data on height and weight including repeated measurements, birth related traits, background variables, education and smoking. By the end of 2014, 48 projects participated. Together, we have 893,458 height and weight measures (52% females) from 434,723 twin individuals, including 201,192 complete twin pairs (40% monozygotic, 40% same-sex dizygotic and 20% opposite-sex dizygotic) representing 22 countries. This project demonstrates that large-scale international twin studies are feasible and can promote the use of existing data for novel research purposes.