Leisure-time physical activity dose-response effects on obesity among African American adults in Indianapolis

Objective: To examine the evidence of dose-response relationship between leisure-time physical activity (LTPA) and obesity among African American adults.

Methods: Data were collected from a cross-sectional sample of 649 African American adults from 27 churches in Indianapolis, Indiana. The primary outcome measure was body mass index (BMI), which was categorized into obese (BMI ≥ 30 kg/m²) and non-obese (BMI < 30 kg/m²) groups. The LTPA was categorized into four groups by the total volume: no-, low-, moderate-, and high-amount of LTPA. Logistic regression analysis was used to examine the association between LTPA and obesity.

Results: Although significant drops in the percentage of obesity between two adjacent groups of LTPA groups were not found, the data show an inverse dose-response relationship between the total volume of LTPA and obesity for African American women, but not for men. In the adjusted female models where daily physical activity and/or demographic characteristics were controlled, however, only high level of LTPA (i.e. 300 minutes or more per week) was significantly associated with a decreased likelihood of being obese compared to those who engaged in no LTPA.

Conclusions: Data uncovered a tendency of an inverse dose-response relationship between total volume of LTPA and obesity in African American women, but not in men. A pronounced benefit of LTPA in preventing obesity appears to occur for African American women who accumulate high volume of LTPA (i.e., 300 minutes or more). Further research is needed to investigate the gender difference in the effect of LTPA on obesity.