Weighing in on the issue: A longitudinal analysis of the individual and contextual factors that influence the developmental trajectories of eating disorders among adolescents

Eating disorders, and variants of these disorders (e.g., body dissatisfaction, weight control behaviors), represent pressing and prevalent health problems that affect American adolescents with potentially chronic consequences (Commission on Adolescent Eating Disorders, 2005). Although the World Health Organization (2003) designated these issues as a global priority area for youth mental health, reaching a complete understanding of the developmental processes that increase and maintain risk and protection is complicated by several unique theoretical and empirical challenges.;In order to address these conceptually and empirically interrelated problems, the current study integrated existing theoretical frameworks derived from the eating disorder literature with relevant perspectives from the adolescent development field, and elaborated a systems-based theoretical framework and methodology for the study of associations among adolescents' experiences pertinent to eating pathology and body dissatisfaction, their patterns of sports participation, and the implications of these associations for their positive and problematic development. Sports participation was examined as the primary contextual factor because of its central role in affecting adolescent development.;Using data from Grades 9 to 11 of the 4-H Study of Positive Youth Development (PYD), this research first identified qualitatively distinct trajectories of adolescents' eating pathology and body dissatisfaction using group-based modeling, and then used multinomial logistic regression analyses to describe the individual and contextual correlates of these pathways. Next, multiple regression analyses were used to examine whether trajectories of eating pathology and body dissatisfaction related to youth positive and problematic development, such as PYD and depression. The final phase of this study investigated whether sports participation moderated associations between specific trajectories of eating pathology and body dissatisfaction and adolescents' positive or problematic development.;Results from the group-based modeling and multinomial logistic analyses supported the presence of qualitatively distinct trajectories of eating pathology and body dissatisfaction that differed with respect to patterns of constancy and change across middle adolescence. In addition, several physical, psychological, and demographic factors were associated with adolescents' membership in specific trajectory groups. In general, the results suggested that boys, adolescents with perceptions of normal weight, and adolescents with higher levels of self-worth, were more likely to be in favorable trajectories of eating pathology and body dissatisfaction. Actual weight (BMI-z) at Grade 9 was related to membership in body dissatisfaction trajectories but not to membership in eating pathology trajectories. Maternal education and duration of sports participation were not associated with membership in any of the eating pathology and body dissatisfaction trajectories.;Findings from the multiple regression analyses demonstrated that diverse eating pathology and body dissatisfaction trajectories were significantly associated with youth positive and problematic functioning, after accounting for specific demographic, physical, and psychological factors. In general, eating pathology and body dissatisfaction trajectories were associated more with adolescents' depression scores than with adolescents' PYD scores. In addition, results suggested that unique patterns of associations between trajectory group membership and psychosocial functioning existed for female and male adolescents. Among girls, experiencing unhealthy or problematic eating- and weight-related trajectories were not only significantly associated with lower levels of PYD, but were also associated with higher levels of depressive symptoms as well. Among males, membership in problematic eating pathology trajectories was associated with more depressive symptoms, although membership in any of the eating- and weight-related trajectories was unrelated with males' positive adjustment. Membership in either favorable or unfavorable eating- and weight-related trajectories was not associated with males' positive adjustment.;Finally, results of multiple regression analyses indicated that sports participation moderated (a) relations between adolescents' experiences in problematic eating- and weight-related trajectories, and (b) their self-reported depressive symptoms. Specifically, for adolescent boys and girls in more problematic trajectories of eating pathology and body dissatisfaction, more continuous sports participation was related to lower levels of depression. However, for adolescents who experienced pathways characterized by lower (although still chronic) levels of eating pathology and body dissatisfaction, more years of sports participation were associated with increased depressive symptoms.;These results suggest that the distinct and diverse pathways of eating pathology and body dissatisfaction that exist across middle adolescence have important implications for the positive and problematic development of our youth. In addition, the findings underscore the need to evaluate the interindividual differences that exist in regard to how sports participation may positively or negatively relate to developmental outcomes.