State-level income inequality and meeting physical activity guidelines; differential associations among US men and women

Background: Previous work has identified a relationship between income inequality and risk for obesity and heart attack. We investigated the relationship between state-level income inequality and physical activity among US adults. Methods: We used Behavioral Risk Factor Surveillance System (BRFSS) cross-sectional data from a population based and representative sample of n = 428 828 US adults. Multilevel models were used to determine the association between state-level income inequality and participation in physical activity and strengthening exercises in the previous month. Results: In comparison to males, females were significantly more likely to report being physically inactive (OR = 1.07, 95% CI = 1.04, 1.11), and less likely to meet aerobic activity requirements (OR = 0.90, 95% CI = 0.88, 0.93), meet strengthening activities (OR = 0.71, 95% CI = 0.69, 0.74), and meet overall physical activity recommendations (OR = 0.91, 95% CI = 0.88, 0.94). Cross-level Gini × sex interactions indicated that income inequality was associated with increased odds for participating in no physical activity (OR = 1.08, 95% CI = 1.05, 1.12), decreased odds in participating in strengthening physical activity (OR = 0.92, 95% CI = 0.89, 0.96), aerobic activity (OR = 0.96, 95% CI = 0.93, 0.99), and in meeting overall physical activity recommendations (OR = 0.93, 95% CI = 0.91, 0.95) among women only. Conclusions: Future studies are needed to identify mechanisms in which income inequality leads to physical activity behavior among US women.