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.