Previous studies suggest strong associations between body-conscious peer groups and disordered eating. This association has been attributed to socialization effects (i.e., membership in peer groups leads to disordered eating); however, selection effects (i.e., selecting into peers group based on genetic or environmental predispositions toward disordered eating) could contribute to or even account for these associations. The current study was the first to use a co-twin control design to disentangle genetic and shared environmental selection factors from pure socialization effects. Participants included 432 female twins (ages 8-14) drawn from the Michigan State University Twin Registry. To comprehensively examine the full range of eating pathology, several disordered eating attitudes and behaviors (e.g., body dissatisfaction, binge eating) were examined via self-report. Self-report questionnaires also were used to assess peer group emphasis on body weight and shape. Replicating previous results, significant within-person associations were found between membership in body-conscious peer groups and disordered eating. However, co-twin control analyses indicated that this association was due entirely to genetic and shared environmental selection factors. Results remained unchanged when controlling for age, BMI, and pubertal status. These findings question the current predominate theory that the association between body-conscious peer groups and disordered eating is due entirely to socialization processes. Future studies are needed to identify the specific genetic and shared environmental factors that may drive selection into body-conscious peer groups.
Read
