Physical activity as a potential mechanism through which social support may reduce cardiovascular disease risk.

Social support has been associated with a reduced risk of cardiovascular disease (CVD). It has been suggested that the protective effect of social support is mediated through the autonomic nervous system and/or unhealthy lifestyle behaviors, but data are sparse, especially in diverse populations. The purpose of this study was to evaluate possible pathways through which social support may reduce cardiovascular disease risk. Baseline data from The National Heart, Lung, and Blood Institute Family Intervention Trial for Heart Health were included in this analysis (N = 501, mean age 48 +/- 13 years, 66% female, 36% nonwhite). Social support was calculated using the Enhancing Recovery in Coronary Heart Disease Patients Social Support Instrument, a validated tool measuring emotional and instrumental support. Emotional support is defined as the belief that one is cared about (high = score > or = 18); instrumental social support is defined as help with services (high = score > or = 3). Demographics, physical activity, and diet were assessed by standardized questionnaires, and cardiovascular disease risk factors were measured systematically. Linear regression models were adjusted for age, race/ethnicity, sex, marital status, and education. Higher instrumental social support was positively associated with minutes of physical activity per week (P = .007). Higher emotional social support was positively associated with number of days of physical activity per week (P = .023), number of servings of wine per week (P = .007), and increased high-density lipoprotein cholesterol (P = .014). A mediational analysis was performed, and the relationship between emotional social support and high-density lipoprotein cholesterol was significantly attenuated by physical activity days per week and number of servings of wine per week. No significant associations were found for other potential mediators tested including body mass index, waist circumference, and intake of omega-3 fatty acids, beer, or liquor. In this ethnically diverse population, emotional social support was linked to higher high-density lipoprotein cholesterol levels through increased physical activity and wine intake, suggesting possible mechanisms through which social support may reduce cardiovascular disease risk.