Abstract 14662: Relationships Between Physical Activity, Coronary Artery Calcium, and Cardiovascular Outcomes in the Multi-Ethnic Study of Atherosclerosis: MESA

Abstract

Introduction: Physical activity is associated with decreased rates of atherosclerotic cardiovascular disease (ASCVD) and mortality. However, high levels of physical activity (PA) have paradoxically been linked with elevated levels of coronary artery calcium (CAC). It remains unclear whether high levels of physical activity in the presence of high CAC are associated with adverse outcomes in a diverse, multi-ethnic population. Hypothesis: We hypothesized that high compared to low levels of PA are associated with a reduction in incident ASCVD and all-cause mortality, even in the presence of high CAC. Methods: Baseline total PA (MET-min/week) in the Multi-Ethnic Study of Atherosclerosis (MESA), obtained via questionnaire, was divided into quartiles. CAC was dichotomized into low (CAC <100 Agatston Units (AU)) and high (CAC ≥100 AU) categories. Outcomes of interest included ASCVD and all-cause mortality. Cox proportional hazard regression analysis was used to assess associations between PA, ASCVD, and all-cause mortality among low and high CAC groups. Results: Among the 6,814 participants included in this study, the average age was 62 years, 53% were female, and 38% were non-Hispanic white. In participants with CAC <100 AU and PA in the highest quartile, we observed a significant reduction in ASCVD and all-cause mortality compared with participants in the lowest PA quartile (Table1). In participants with CAC ≥100 AU and PA in the highest quartile, we observed a significant reduction in all-cause mortality, but no difference in the risk of ASCVD compared with participants in the lowest PA quartile. Conclusions: Our study suggests that high levels of PA are associated with a reduced risk of ASCVD and all-cause mortality among individuals with low CAC, and a reduced risk of all-cause mortality among individuals with high CAC. There was no evidence to suggest an increased risk of ASCVD from high levels of PA in individuals with high CAC.