title: A comparison of twin birthweight data from Australia, the Netherlands, the United States, Japan, and South Korea: are genetic and environmental variations in birthweight similar in Caucasians and East Asians?
abstract: Birthweight has implications for physical and mental health in later life. Using data from Caucasian twins collected in Australia, the Netherlands and the United States, and from East Asian twins collected in Japan and South Korea, we compared the total phenotypic, genetic and environmental variances of birthweight between Caucasians and East Asians. Model-fitting analyses yielded four major findings. First, for both males and females, the total phenotypic variances of birthweight were about 45% larger in Caucasians than in East Asians. The larger phenotypic variances were mainly attributable to a greater shared environmental variance of birthweight in Caucasians (ranging from 62% to 67% of variance) than Asians (48% to 53%). Second, the genetic variance of birthweight was equal in Caucasians and East Asians for both males and females, explaining a maximum of 17% of variance. Third, small variations in total phenotypic variances of birthweight within Caucasians and within East Asians were mainly due to differences in nonshared environmental variances. We speculate that maternal effects (both genetic and environmental) explain the large shared environmental variance in birthweight and may account for the differences in phenotypic variance in birthweight between Caucasians and East Asians. Recent molecular findings and specific environmental factors that are subsumed by maternal effects are discussed.
authors.affiliation: Seoul National University Hospital, Seoul, South Korea. ymhur@neuroimage.snu.ac.kr
authors.forename: Yoon-Mi
authors.initials: YM
authors.lastname: Hur
authors.forename: Michelle
authors.initials: M
authors.lastname: Luciano
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Martin
authors.forename: Dorret I
authors.initials: DI
authors.lastname: Boomsma
authors.forename: William G
authors.initials: WG
authors.lastname: Iacono
authors.forename: Matt
authors.initials: M
authors.lastname: McGue
authors.forename: Joong Sik
authors.initials: JS
authors.lastname: Shin
authors.forename: Jong Kwan
authors.initials: JK
authors.lastname: Jun
authors.forename: Syuichi
authors.initials: S
authors.lastname: Ooki
authors.forename: C E M
authors.initials: CE
authors.lastname: van Beijsterveldt
authors.forename: Jung Yeol
authors.initials: JY
authors.lastname: Han
mesh_terms: D044466:Asian People; D001724:Birth Weight / Q000235:genetics*; D004777:Environment; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D018811:Maternal Exposure; D010641:Phenotype; D012189:Retrospective Studies; D014427:Twins / Q000235:genetics*; D044465:White People