PHYSICAL INACTIVITY, BUT NOT SEDENTARY BEHAVIOR OR ENERGY INTAKE, IS ASSOCIATED WITH HIGHER FAT MASS IN LATINA AND AFRICAN AMERICAN GIRLS

Background: Minority girls are disproportionately affected by overweight and obesity. The independent effects of physical activity (PA), sedentary behavior (SB), and diet are not well understood. Objective: This study examined the individual influences of PA, SB and diet on fat mass in Latina and African American (M) girls, aged 8-11. Methods: Baseline data from a longitudinal cohort study in minority girls is presented. Multiple linear regression analysis assessed the effects of PA, SB, and energy intake on fat mass, adjusting for lean mass, age, Tanner stage and ethnicity. Results: Participants were 53 Latina and AA girls (77% Latina; M-age=9.8 +/- .9; M-BMI%=80.8 +/- 23.1). Moderate-to-vigorous physical activity (MVPA) by accelerometry (beta=-.13, P<.01) and lean mass(beta=.69, P<.001) were associated with fat mass (Model R-2=.63; P<.0001). MVPA by 3-day-physical-activity-recall (beta=-.04, P=.01) and lean mass (beta=.75, P<.001) were associated with fat mass (Model R-2=.61; P<.0001). SB and energy intake were not associated with fat mass in any model. Conclusion: Using both objective and subjective measures of PA, MVPA, but not SB or diet, was associated with higher fat mass in Latina and AA girls, independent of lean mass, age, Tanner stage, and ethnicity. Prospective studies are needed to clarify the differential impact of diet and activity levels on adiposity in this population. (Ethn Dis. 2011;21 (4):458-461)