AIM: To investigate how being born and raised as a twin is associated with IQ, educational achievement and vocational career. METHODS: Register study in a national birth cohort, complemented with a siblings study. The study population included 13,368 individuals born and raised as twins and 837,752 singletons, including 3019 siblings of twins, in the Swedish birth cohorts of 1973-1981. Our outcome measures were mean grade points on a five point scale from ninth grade of primary school at 15-16 years, IQ tests on a nine grade point scale from male conscripts at 18-19 years, highest completed education, disability benefits, work income and employment at 27-35 years of age. RESULTS: Twins had slightly better mean grade point averages in ninth grade; +0.08 (95% CI 0.04-0.11) and more often had completed a university education in young adulthood; OR 1.16 (1.02-1.21) compared with singleton siblings, despite male twins having a slightly lower IQ at military conscription compared with male singletons. Employment rates, mean income and disability benefits were similar in twins and singletons. CONCLUSIONS: Twins have slightly better educational careers and similar vocational careers compared with those born as singletons.
AIM: To investigate how being born and raised as a twin is associated with IQ, educational achievement and vocational career. METHODS: Register study in a national birth cohort, complemented with a siblings study. The study population included 13,368 individuals born and raised as twins and 837,752 singletons, including 3019 siblings of twins, in the Swedish birth cohorts of 1973-1981. Our outcome measures were mean grade points on a five point scale from ninth grade of primary school at 15-16 years, IQ tests on a nine grade point scale from male conscripts at 18-19 years, highest completed education, disability benefits, work income and employment at 27-35 years of age. RESULTS: Twins had slightly better mean grade point averages in ninth grade; +0.08 (95% CI 0.04-0.11) and more often had completed a university education in young adulthood; OR 1.16 (1.02-1.21) compared with singleton siblings, despite male twins having a slightly lower IQ at military conscription compared with male singletons. Employment rates, mean income and disability benefits were similar in twins and singletons. CONCLUSIONS: Twins have slightly better educational careers and similar vocational careers compared with those born as singletons.
Authors: Karri Silventoinen; Aline Jelenkovic; Antti Latvala; Reijo Sund; Yoshie Yokoyama; Vilhelmina Ullemar; Catarina Almqvist; Catherine A Derom; Robert F Vlietinck; Ruth J F Loos; Christian Kandler; Chika Honda; Fujio Inui; Yoshinori Iwatani; Mikio Watanabe; Esther Rebato; Maria A Stazi; Corrado Fagnani; Sonia Brescianini; Yoon-Mi Hur; Hoe-Uk Jeong; Tessa L Cutler; John L Hopper; Andreas Busjahn; Kimberly J Saudino; Fuling Ji; Feng Ning; Zengchang Pang; Richard J Rose; Markku Koskenvuo; Kauko Heikkilä; Wendy Cozen; Amie E Hwang; Thomas M Mack; Sisira H Siribaddana; Matthew Hotopf; Athula Sumathipala; Fruhling Rijsdijk; Joohon Sung; Jina Kim; Jooyeon Lee; Sooji Lee; Tracy L Nelson; Keith E Whitfield; Qihua Tan; Dongfeng Zhang; Clare H Llewellyn; Abigail Fisher; S Alexandra Burt; Kelly L Klump; Ariel Knafo-Noam; David Mankuta; Lior Abramson; Sarah E Medland; Nicholas G Martin; Grant W Montgomery; Patrik K E Magnusson; Nancy L Pedersen; Anna K Dahl Aslan; Robin P Corley; Brooke M Huibregtse; Sevgi Y Öncel; Fazil Aliev; Robert F Krueger; Matt McGue; Shandell Pahlen; Gonneke Willemsen; Meike Bartels; Catharina E M van Beijsterveldt; Judy L Silberg; Lindon J Eaves; Hermine H Maes; Jennifer R Harris; Ingunn Brandt; Thomas S Nilsen; Finn Rasmussen; Per Tynelius; Laura A Baker; Catherine Tuvblad; Juan R Ordoñana; Juan F Sánchez-Romera; Lucia Colodro-Conde; Margaret Gatz; David A Butler; Paul Lichtenstein; Jack H Goldberg; K Paige Harden; Elliot M Tucker-Drob; Glen E Duncan; Dedra Buchwald; Adam D Tarnoki; David L Tarnoki; Carol E Franz; William S Kremen; Michael J Lyons; José A Maia; Duarte L Freitas; Eric Turkheimer; Thorkild I A Sørensen; Dorret I Boomsma; Jaakko Kaprio Journal: Twin Res Hum Genet Date: 2017-10 Impact factor: 1.587
Authors: Oluwole A Babatunde; Sally N Adebamowo; IkeOluwa O Ajayi; Clement A Adebamowo Journal: Twin Res Hum Genet Date: 2018-02-08 Impact factor: 1.587
Authors: Nóra Kerekes; Sebastian Lundström; Zheng Chang; Armin Tajnia; Patrick Jern; Paul Lichtenstein; Thomas Nilsson; Henrik Anckarsäter Journal: PeerJ Date: 2014-04-22 Impact factor: 2.984
Authors: Danilo Garcia; Sebastian Lundström; Sven Brändström; Maria Råstam; C Robert Cloninger; Nóra Kerekes; Thomas Nilsson; Henrik Anckarsäter Journal: PLoS One Date: 2013-08-05 Impact factor: 3.240