Changes in genetic and environmental influences on disordered eating across adolescence - A longitudinal twin study

Context: Previous research suggests substantial increases in genetic effects on disordered eating across adolescence. Unfortunately, these studies were crosssectional and focused primarily on early (age 11 years) vs late (age 17 years) adolescence. Objective: To examine longitudinal changes in genetic and environmental influences on disordered eating across early, mid, and late adolescence. Design and Setting: Population-based study of female same-sex twins. Participants: Seven hundred seventy-two female adolescent twins from the Minnesota Twin Family Study assessed at ages 11, 14, and 18 years. Main Outcome Measures: Disordered eating symptoms (ie, body dissatisfaction, weight preoccupation, binge eating, and the use of compensatory behaviors) were assessed with the total score from the Minnesota Eating Behavior Survey. Results: Biometric model-fitting indicated significant changes in genetic and shared environmental effects across early to mid adolescence. Although genetic factors accounted for a negligible proportion (6%) of variance at age 11 years, genes increased in importance and accounted for roughly half of the variance (46%) in disordered eating at ages 14 and 18 years. Shared environmental influences decreased substantially across these same ages. Conclusions: Findings highlight the transition from early to mid adolescence as a critical time for the emergence of a genetic diathesis for disordered eating. The increase in genetic effects during this developmental stage corroborates previous research implicating puberty in the genetic etiology of eating disorders.