A Study of Changes in Genetic and Environmental Influences on Weight and Shape Concern Across Adolescence

Abstract

The goal of the current study was to examine whether genetic and environmental influences on an important risk factor for disordered eating, weight and shape concern (WSC), remained stable over adolescence. This stability was assessed in two ways: whether new sources of latent variance were introduced over development, and whether the magnitude of variance contributing to the risk factor changed. We examined an 8-item WSC sub-scale derived from the Eating Disorder Examination using telephone interviews with female adolescents. From three waves of data collected from female-female same sex twin pairs from the Australian Twin Registry, a subset of the data (which included 351 pairs at Wave 1) was used to examine three age cohorts: 12-13, 13-15, and 14-16 years. The best fitting model contained genetic and environmental influences, both shared and non-shared. Biometric model fitting indicated that non-shared environmental influences were largely specific to each age cohort, and results suggested that latent shared environmental and genetic influences that were influential at 12-13 years continued to contribute to subsequent age cohorts, with independent sources of both emerging at ages 13-15. The magnitude of all three latent influences could be constrained to be the same across adolescence. Ages 13-15 was indicated as a time of risk for the development of high levels of WSC given that most specific environmental risk factors were significant at this time (e.g., peer teasing about weight, adverse life events), and indications of the emergence of new sources of latent genetic and environmental variance over this period.