Sleep and obesity: the mediating role of health behaviors among African Americans

Objectives: To examine the role of health behaviors (eg, physical activity, sedentary behaviors, and diet) in the relationship between sleep (ie, duration and quality) and BMI among African American adults. Design: A cross-sectional self-report questionnaire included questions related to health and health-related behaviors. Setting: This study was based on data from the CHURCH study, which aimed to address cancer health disparities among church-going African Americans in Houston, TX. Participants: African American adults were recruited from three large community churches. The sample included a total of 1837 participants (75.2% female; mean age 48.2 ± 13.7y; mean BMI 32.0 ± 7.5 kg/m²). Measurements: Linear regression models and path analyses controlling for demographic characteristics and depression estimated the associations between sleep and BMI as well as the mediating roles of health behaviors. Results: The average self-reported sleep duration was 6.2 ± 1.5 h/night with 61%, 35.8%, and 1.6% reporting short (≤6 h/night), normal (7–9 h/night), and long sleep (≥10 h/night), respectively. Short sleep was related to greater BMI (b = 1.37, SE = 0.38, P =.01), and the relationship was mediated by sedentary behaviors (est. = 0.08, SE = 0.04, 95% CI: 0.02, 0.17). Conclusions: Short sleep and poor quality sleep was related to poor diet and physical activity-related health behaviors, and BMI. The link between sleep and obesity is, in part, due to energy imbalance from increased sedentary behavior.