Associations Among Cardiorespiratory Fitness, Coronary Artery Calcium Score and Coronary Heart Disease In Men

Abstract

0931 Coronary artery calcium score (CAC) is a strong predictor of future coronary heart disease (CHD) independent of traditional risk factors. Cardiorespiratory fitness (CRF) is inversely related to the development of CHD. The effect of CRF on CHD in individuals with elevated CAC (100 or greater) has yet to be examined. PURPOSE: To determine if higher levels of CRF attenuate the risk of CHD in men with CAC of at least 100. METHODS: 2451 men completed at least one medical examination that included an electron beam tomographic scan at the Cooper Clinic in Dallas, TX between 1995 and 2000 and returned a mail-back questionnaire. CHD was defined as the presence of any of the following endpoints: CHD death, non-fatal myocardial infarction, coronary artery bypass surgery and percutaneous coronary revascularization. CAC was quantified using an Agatston score. Quintiles of CRF (Q1-Q5) were based on the duration of a maximal treadmill test. RESULTS: 658 men had a CAC of at least 100. Of those, 58 men reported a CHD event. The highest rates of CHD per 1000 manyears of observation were in Q1 (94.9) and the lowest rates were in Q5 (15.1). Based on results from a proportional hazards model that included age; CAC; and the history of hypertension, diabetes and hypercholesterolemia the risk of CHD was inversely related to CRF level. With Q1 as the referent group, the relative risks and 95% confidence intervals for Q2-Q5 were 0.44, 0.20–0.94; 0.24, 0.20–0.94; 0.22, 0.10–0.57; and 0.15, 0.07–0.35, respectively. CONCLUSION: In men with an elevated CAC, higher levels of CRF were related to a lower risk of developing clinical CHD events. Supported by NIH grant HL62508-04