The association between physical activity and both incident coronary artery calcification and ankle brachial index progression: The Multi-Ethnic Study of Atherosclerosis

Objective: Both coronary artery calcification (CAC) and the ankle brachial index (ABI) are measures of subclinical atherosclerotic disease. The influence of physical activity on the longitudinal change in these measures remains unclear. To assess this relation we examined the association between these measures and self-reported physical activity in the Multi-Ethnic Study of Atherosclerosis (MESA). Methods: At baseline, the MESA participants were free of clinically evident cardiovascular disease. We included all participants with an ABI between 0.90 and 1.40 (n = 5656). Predictor variables were based on self-reported measures with physical activity being assessed using the Typical Week Physical Activity Survey from which metabolic equivalent-minutes/week of activity were calculated. We focused on physical activity intensity, intentional exercise, sedentary behavior, and conditioning. Incident peripheral artery disease (PAD) was defined as the progression of ABI to values below 0.90 (given the baseline range of 0.90-1.40). Incident CAC was defined as a CAC score >0 Agatston units upon follow up with a baseline score of 0 Agatston units. Results: Mean age of participants was 61 years, 53% were female, and mean body mass index was 28 kg/m(2). After adjusting for traditional cardiovascular risk factors and socioeconomic factors, intentional exercise was protective for incident peripheral artery disease (Relative Risk (RR) = 0.85, 95% Confidence Interval (CI): 0.74-0.98). After adjusting for traditional cardiovascular risk factors and socioeconomic factors, there was a significant association between vigorous PA and incident CAC (RR = 0.97, 95% CI: 0.94-1.00). There was also a significant association between sedentary behavior and increased amount of CAC among participants with CAC at baseline (Delta log (Agatston Units + 25) = 0.027, 95% CI 0.002, 0.052). Conclusions: These data suggest that there is an association between physical activity/sedentary behavior and the progression of two different measures of subclinical atherosclerotic disease. (C) 2013 Elsevier Ireland Ltd. All rights reserved.