Physical activity and central adiposity in a cohort of African-American adults.

Background: Visceral adipose tissue (VAT) is known as an independent predictor of cardiometabolic risk and all-cause mortality, while increased physical activity has been shown to improve cardiometabolic risk. The purpose of the present study was to determine whether or not there is an association between objectively-measured physical activity and VAT in a community-based cohort of African-American adults, a population at higher-than-average risk for cardiometabolic diseases.

Methods: Free-living physical activity was quantified using accelerometry while VAT and abdominal subcutaneous fat were estimated using dual x-ray absorptiometry in a cohort of African Americans, ages 30-50 years, enrolled in the Modeling the Epidemiologic Transition Study. Univariate and multivariate analyses were used to determine the degree of association comparing moderate-to-vigorous physical activity (MVPA), vigorous activity, and sedentary behavior with measures of central adiposity including VAT, subcutaneous fat, and waist circumference.

Results: A total of 271 individuals with complete data were included in the analyses. Women, on average, had significantly more VAT and abdominal subcutaneous fat than men. There were statistically significant inverse univariate correlations between MVPA and measures of abdominal adiposity (-0.30, p < 0.001) and activity counts and adiposity (-0.31, p < 0.001) among both sexes. These significant associations remained after controlling for age, sex, and smoking status; neither alcohol consumption nor employment status were associated with abdominal adiposity. Time in sedentary behavior was not meaningfully associated with central adiposity in either sex (women: -0.02, p = 0.79; men: -0.21, p = 0.04).

Conclusions: To our knowledge, this study is the first to identify significant inverse associations between MVPA and measures of central adiposity among African American adults from a community-based cohort using an objective measure of physical activity and a validated quantitative imaging technique.