HOW PHYSICAL ACTIVITY IMPACTS THE RELATIONSHIP BETWEEN PSYCHOSOCIAL FACTORS AND CARDIOVASCULAR EVENTS: RESULTS FROM THE MULTI-ETHNIC STUDY OF ATHEROSCLEROSIS
Natalie Gasca1, Randy Cohen2,3, Robyn McClelland1, David Jacobs4, Steven Shea5.
1University of Washington, Seattle, WA, 2Division of Cardiology, Mt. Sinai St. Luke's Hospital, New York, NY, 3Roosevelt Hospital, New York, NY, 4Division of Epidemiology, University of Minnesota, Minneapolis, MN, 5Columbia University, New York, NY.
Depression and chronic stress are strongly associated with higher risks of cardiovascular disease (CVD); by contrast, physical activity promotes psychological health, ameliorates depressive symptoms, and is associated with fewer CVD events. To facilitate preventive interventions for CVD-free individuals, this study investigated how self-reported physical activity modifies the association between CVD and depression, as well as CVD and chronic stress, in ethnically-diverse subjects without baseline CVD. This study included 6,795 Multi-Ethnic Study of Atherosclerosis (MESA) cohort participants with complete data on physical activity (mean age = 62 years; 47% male). A baseline exam in 2000-2002 assessed exercise, depression, and chronic stress; CVD was evaluated over 10 years. Intentional exercise was categorized into low, intermediate, and high levels corresponding to 0 - 449, 450 - 1,349, and at least 1,350 metabolic equivalent minutes/week. Cox proportional hazard models were constructed to estimate the association between depression (chronic stress) and CVD stratified by exercise levels and adjusted for age, gender, and race. The hazard ratios of CVD, comparing participants with depression to those without, within each exercise level, (1.21, p = 0.266; 2.08, p < 0.001; 0.99, p = 0.965) peaked at the intermediate exercise level. Comparing those with and without chronic stress, the hazard ratios for CVD (1.22, p = 0.001; 1.14, p = 0.093; 1.03, p = 0.699) decreased as exercise level increased. However, only the interaction between depression and exercise was significant (p = 0.008). Although exercise itself was protective, only high levels of physical activity weakened the relationship between each psychosocial factors and CVD. Future research should examine the effects of high exercise intensities on CVD risk among individuals with psychosocial burdens.