Socioeconomic status, race, and body mass index: the mediating role of physical activity and sedentary behaviors during adolescence.

OBJECTIVE To assess how sociodemographic and activity behaviors contribute to adolescent body mass index (BMI). METHODS One hundred and thirteen adolescents (M = 17 years; 42% Caucasian, 56% African American) were assessed on BMI. Teens reported activity levels and caregivers reported socioeconomic status (SES). RESULTS Adolescents from lower SES backgrounds, and from minority groups, had higher BMI (r = -.26, p < .01 and t(110) = -3.01, p < .01). Formal statistical mediation tests revealed that sedentary behaviors significantly mediated the association between SES and BMI (Z = 2.31, p < .05), whereas physical activity significantly mediated the race-BMI association (Z = 2.32, p < .05). CONCLUSIONS Interventions targeting teen BMI could benefit by aiming to decrease sedentary behavior in low SES teens and increase physical activity in teens from minority groups.