Associations between friends' disordered eating and muscle-enhancing behaviors.

Dieting, unhealthy weight control and muscle-enhancing behaviors are common among adolescents: friends are a probable source of influence on these behaviors. The present study uses data provided by nominated friends to examine associations between friends' disordered eating and muscle-enhancing behaviors and participants' own behaviors in a diverse sample of American youth. Male and female adolescents (mean age = 14.4) completed surveys and identified their friends from a class roster; friends' survey data were then linked to each participant. Participants (N = 2126) who had at least one nominated friend were included in the analytic sample. Independent variables were created using the same weight control and muscle-enhancing behaviors reported by nominated friends, and were used in logistic regression models to test associations between participants' and their friends' behaviors, stratified by gender. Results indicated that dieting, disordered eating and muscle-enhancing behaviors were common in this sample, and selected friends' behaviors were associated with the same behaviors in participants. For example, girls whose friends reported extreme weight control behaviors had significantly greater odds of using these behaviors than girls whose friends did not report these same behaviors (OR = 2.39). This research suggests that friends' weight- and shape-related behaviors are a feature of social relationships, and is the first report demonstrating these associations for muscle-enhancing behaviors. Capitalizing on the social element may be important to the development of increasingly effective intervention and prevention programs.