SES-of-Origin and BMI in Youth: Comparing Germany and Minnesota - to be part of symposium 'Gene x Environment Interplay on Indicators of Social Inequality'

BMI consistently shows considerable genetic but also shared environmental variance across the lifespan, the latter particularly at younger ages. Several studies to date have observed less total and genetically influenced... [ view full abstract ]

BMI consistently shows considerable genetic but also shared environmental variance across the lifespan, the latter particularly at younger ages. Several studies to date have observed less total and genetically influenced variance with higher attained SES in adults, but we are unaware of analogous studies of SES-of-origin in youth samples. Moreover, there is no reason to expect the same proportions of genetic and environmental influences and moderating effects of SES in different countries with different health policies, lifestyles, and degrees of social inequality. We examined SES-of-origin moderation of BMI variance in the German TwinLife study's four birth cohorts, ranging in age from 5 to 25, and in the Minnesota Twin Family Study's two birth cohorts at ages 11, 17, and 24, comparing males and females separately. In general we observed much stronger SES moderation of environmental than genetic influences, in contrast to studies of attained-SES moderation of BMI in adults. We discuss between-country and between-sex differences in our SES-of-origin observations, interpreting them in light of the inevitably-missing covariance between SES-of-origin and BMI in our models, mother-father and parent-offspring BMI correlations, and analogous attained-SES observations in adult samples.