School socioeconomic makeup predicts weight status of students

Adolescent obesity is a significant public health problem disproportionately affecting African-American, Hispanic, and poor adolescents. Schools may influence the weight status of teens through a number of different mechanisms and may contribute to disparities in BMI. In order to assess the influence of schools and their attributes on individual BMI we analyzed baseline data from 17,007 teens participating in the nationally representative National Longitudinal Study of Adolescent Health. Adolescents attended schools that were segregated by race/ethnicity and socioeconomic status. In females when controlling only for individual level attributes, individual household income was inversely associated (gamma=-0.0073, p=0.001) while Hispanic (gamma=0.72, p<0.001) and African-American (gamma=1.51, p<0.001) race/ethnicity were positively associated with BMI. In males, African-American (gamma=0.28, p=0.029) and Hispanic (gamma=0.63, p<0.001) race/ethnicity were positively associated with BMI though individual household income was not associated (gamma=-0.0022, p=0.28). After controlling for the school racial/ethnic makeup and the school level median household income, the relationship of race/ethnicity and BMI was attenuated and in males, the association between African-American race/ethnicity and BMI was no longer significant (gamma=0.26, p=0.062). Higher school level median household income was associated with lower individual BMIs in adolescent girls (gamma=-0.042, p<0.001) and boys (gamma=-0.029, p=0.002) suggesting a contextual effect of the school. The racial/ethnic makeup of the school was not associated with BMI in either females (gamma=0.089; p=0.52) or males (gamma=0.23; p=0.082). More research is needed to identify mechanisms (i.e. physical activity opportunities or availability of healthy lunches) through which school contexts influence the weight status of adolescent students.