Exploring the relationship of stress on HPA-Axis dysregulation and BMI in African Americans: Findings from the CARDIA Study

Background/Significance: Obesity affects African Americans at a rate of 35.7% compared to 28.7% in Hispanics and 23.7% in Whites. African Americans experience more chronic stress than the general population, due to social inequality including racial discrimination, thereby increasing the risk for overweight and obesity. Research on stress and obesity documents the importance of HPA-Axis dysregulation and the release of cortisol on BMI. However, to date, research has not explored the modifying effect of social support on the relationship between chronic stress and HPA-Axis dysregulation and chronic stress and BMI in African Americans. Hypotheses: H1. Low diurnal (waking) cortisol levels will predict higher BMI in African Americans. H2. Higher levels of stress will predict lower diurnal cortisol levels and higher BMI in African Americans. H3. Diurnal cortisol levels will mediate the affect of chronic stress on health behavior (fast food intake) and on BMI. H4. Social support will modify the effect of chronic stress on diurnal cortisol and on BMI. Method: The Coronary Artery Risk Development in Young Adults (CARDIA) Study is a longitudinal population based observational study of the National Institutes of Health National Heart Lung and Blood Institute (NHLBI). We examine a cross section of the Black population (n=1722) of the CARDIA Study. Using a measure of chronic stress (chronic burden) and other variables we explore changes in HPA-Axis dysregulation (using diurnal/waking decline of salivary cortisol) and BMI (m=28.64). Data will be analyzed using a combination of bivariate and multivariate statistics. Implications of the findings will be discussed.