Sex Differences in the Relation Between Body Mass Index Trajectories and Adolescent Social Adjustment

Most research on weight-related social difficulties in adolescence emphasizes categorical measures of weight status (e.g., overweight/obese vs. non-overweight/non-obese). However, teens who are not overweight can also experience weight-related social adjustment problems, and girls may be at higher risk for maladjustment due to weight-related stigmatization than their male counterparts. The current study modeled trajectories of BMI z-score (zBMI), a continuous measure of BMI relative to U.S. reference standards for child age and sex, for boys and girls from ages 9 to 15. The sample of 938 adolescents, drawn from the Study of Early Child Care and Youth Development, contained proportions of normal weight and overweight/obese teens that approximate the U.S. population. Latent growth curve modeling was used to establish quadratic models describing zBMI change in boys and girls separately using measurements collected at ages 9, 10.5, 11.5, 12.5, 13.5, and 15.5. zBMI growth parameters were used to predict a latent social adjustment variable indicated by mother and adolescent reports of adaptive social functioning at age 15. Controlling for pubertal timing, socioeconomic status, race/ethnicity, the proportion of measurements at which children were classified as overweight, and age 9 social adjustment, girls' more rapid BMI gains across the pubertal transition, and greater acceleration of these growth rates relative to national norms were associated with lower age 15 social adjustment. Findings suggest that a better understanding of weight-related social adjustment may require broadening the scope of research and intervention efforts to normal-weight teens, particularly normal-weight girls.