Physical activity and obesity gap between black and white women in the southeastern U.S

Differences between black and white women in the associations of sedentary and active behaviors and obesity are mostly unknown.

To examine associations of sedentary and active behaviors with BMI, a marker of overall obesity, in a large group of black and white women and to determine whether there are differences by race in these associations.

Associations between time spent in sedentary and active behaviors and BMI were examined using cross-sectional data collected from 2002 to 2006 at enrollment into the Southern Community Cohort Study (SCCS) from 22,948 black and 7830 white women living in the southeastern U.S. These associations were examined using linear and polytomous logistic regression models controlling for age, race, income, education, occupational status, tobacco use, marital status, and comorbidities.

Time spent in sedentary behaviors was directly related to BMI whereas time spent in active behaviors such as moderate and vigorous physical activity was inversely related to BMI, with stronger associations for whites than blacks. White women in the highest quartile of sedentary behaviors were more likely to be moderately (BMI=30-39) or severely (BMI>40) obese than women in the lowest quartile (OR=2.3, 95% CI=1.8, 2.9 for moderate, and OR=4.0, 95% CI=3.1, 5.3 for severe obesity), whereas the ORs among similarly sedentary black women were modestly elevated (ORs of 1.4, 95% CI=1.2, 1.6; and 1.6, 95% CI=1.4, 1.8).

There are significant differences in the association of physical activity patterns and obesity between black and white women living in the southeastern U.S. Although most guidelines for prevention of obesity and maintaining weight promote increased time in moderate and vigorous physical activity, these results indicate that a reduction in sedentary behavior time may represent another useful strategy in this population.