Abstract MP013: Strong Inverse Relation between Physical Activity and Incidence of Cardiovascular Disease in African Americans: the Atherosclerosis Risk in Communities Study

Abstract

Introduction: Although there is substantial evidence that physical activity reduces risk of cardiovascular disease (CVD), the few studies that included African Americans offer inconclusive evidence and did not study stroke and heart failure separately. Objective: We examined, in African Americans and Caucasians in the Atherosclerosis Risk in Communities study (ARIC), the association of physical activity with CVD incidence (n=1,039) and its major components - stroke (n=350), heart failure (n=633), and coronary heart disease (n=442) - over a follow-up period of 21 years. Methods: ARIC is a population-based biracial cohort study of 45– to 64-yr-old adults at the baseline visit in 1987–89. Physical activity was assessed using the modified Baecke physical activity questionnaire and categorized by the American Heart Association’s ideal CVD health guidelines: poor, intermediate, and ideal physical activity. An incident CVD event was defined as the first occurrence of 1) heart failure, 2) definite or probable stroke, or 3) coronary heart disease, defined as a definite or probable myocardial infarction or definite fatal coronary heart disease. Results: We included 3,707 African Americans and 10,018 Caucasians free of CVD at the baseline visit. After adjustment for age, sex, cigarette smoking, alcohol intake, hormone therapy use, education, and ‘Western’ and ‘Prudent’ dietary pattern scores, higher physical activity was inversely related to CVD, heart failure, and coronary heart disease incidence in African Americans and Caucasians (p-values for trend tests <.0001), and with stroke in African Americans. Hazard ratios (95% confidence intervals) for CVD for intermediate and ideal physical activity, respectively, compared to poor, were similar by race: 0.65 (0.56, 0.75) and 0.59 (0.49, 0.71) for African Americans, and 0.74 (0.66, 0.83) and 0.67 (0.59, 0.75) for Caucasians (p-value for interaction = 0.38). Physical activity was also associated similarly in African Americans and Caucasians for each of the individual CVD outcomes (coronary heart disease, heart failure, and stroke), with an approximate one-third reduction in risk for intermediate and ideal physical activity versus poor physical activity- this reduction was statistically significant. Conclusions: In conclusion, our findings reinforce public health recommendations that regular physical activity is important for CVD risk reduction, including reductions in stroke and heart failure. They provide strong new evidence that this risk reduction applies to African Americans as well as Caucasians and support the idea that some physical activity is better than none.