Abstract MP15: Physical Activity is Inversely Associated with Calcified Atherosclerotic Plaque in the Coronary Arteries: The NHLBI Family Heart Study

Abstract

Background: Physical activity is integral to the primary prevention of cardiovascular diseases. However, studies have reported mixed findings on the association between physical activity and coronary artery calcification (CAC). Hypothesis: Our primary hypothesis is that physical activity is inversely associated with prevalent CAC. Methods: In a cross-sectional design, we studied 2,971 participants of the NHLBI Family Heart Study without a history of MI, CABG or PTCA. A standardized questionnaire was used to ascertain the number of blocks walked daily to compute block metabolic equivalent hours per week. CAC was measured by cardiac CT, and we defined prevalent CAC using an Agatston score of at least 100. Generalized estimating equations were used to calculate adjusted prevalence ratios of CAC. Results: Mean age was 55 (±12.7) years and 60.3% of participants were women. Compared to 0-4 blocks/d, prevalence ratios for CAC after adjusting for age, sex, race, BMI, hyperlipidemia, hypertension, diabetes, smoking, and alcohol abuse were 0.73, 95% CI: 0.55-0.97 for >4-8 blocks/d, 0.72, 95% CI: 0.58-0.89 for >8-20 blocks/d, and 0.82, 95% CI: 0.62-1.1 for >20 blocks/d, p for trend 0.02. Corresponding values for total block activity were 0.84, 95% CI: 0.53-1.30 for 1-4 met-hrs/wk, 0.50, 95% CI: 0.31- 0.81 for >4-7 met-hrs/wk, 0.68, 95% CI: 0.47-1.00 for >7-14 met-hrs/wk, and 0.54, 95% CI: 0.33-0.88 for >14-22 met-hrs/wk, p for trend 0.04 (Table 1). In a secondary analysis stratified by BMI (<25 and ≥25 kg/m2), the results remained statistically significant for those with BMI ≥ 25 (p=0.01). The number of participants with BMI < 25 was too small for analysis. The inverse association persisted when we repeated the main analyses using CAC cutoffs of 150 and 200, but not 50. Conclusion: The Family Heart Study data are consistent with an inverse association of mild to moderate physical activity with coronary artery calcification in adult men and women.