Relation of Cardiorespiratory Fitness to Risk of Subclinical Atherosclerosis in Men With Cardiometabolic Syndrome

Abstract

We tested the hypothesis that cardiometabolic syndrome (CMS) is associated with subclinical atherosclerosis in men and that moderate-to-high levels of cardiorespiratory fitness (fitness) attenuate this relation. Our study population (n= 2,107 men) participated in a health screening program that included measures of coronary artery calcification (CAC) and carotid artery intima-media thickness (CIMT) as surrogate markers of subclinical atherosclerosis. The prevalence of subclinical atherosclerosis was defined as a CAC score >0 and a mean CIMT more than the seventy-fifth percentile. Fitness was directly measured through peak oxygen consumption during cardiopulmonary exercise testing to volitional fatigue/exhaustion. The presence of CMS was defined as having ≥3 relevant risk factors based on the Adult Treatment Panel III report (ATP-III) criteria. After adjusting for confounding variables, participants with CMS demonstrated a higher odds ratio (OR) of having a positive CAC (OR 1.41, 95% confidence interval [CI] 1.05 to 1.89) and CIMT (OR 1.70, 95% CI 1.14 to 2.52) compared with those without CMS. Upper levels of fitness were associated with a lower prevalence of CAC (OR 0.69, 95% CI 0.55 to 0.88) and CIMT (OR 0.53, 95% CI 0.40 to 0.71) compared with lower fitness. In the joint analysis, unfit participants with CMS were 1.47 times (95% CI 1.09 to 1.96 for CAC) and 2.35 times (95% CI 1.70 to 3.26 for CIMT) more likely to exhibit these indexes of subclinical atherosclerosis compared with fit participants without CMS. Fit participants with CMS had ORs for the prevalence of CAC (OR 1.12; 95% CI 0.85 to 1.47) and CIMT (OR 1.06; 95% CI 0.74 to 1.53) that were similar to those of the fit cohort without CMS. In conclusion, our findings demonstrate that CMS is associated with an increased risk of subclinical atherosclerosis but that high fitness appears to attenuate these associations in men.