Cardiorespiratory Fitness and the Progression of Carotid Atherosclerosis in Middle-Aged Men

BACKGROUND: Good cardiorespiratory fitness has been associated with reduced risk for clinical events of atherosclerotic vascular diseases, but whether it is related to slower progression of early atherosclerosis is unclear. OBJECTIVE: To study the association between cardiorespiratory fitness and the progression of early carotid atherosclerosis. DESIGN: 4-year follow-up study. SETTING: Eastem Finland. PARTICIPANTS: Population-based sample of 854 men 42 to 60 years of age. MEASUREMENTS: Maximal oxygen uptake (VO2max [mL/kg per minute]) was measured directly by using respiratory gas exchange in a cycle ergometer exercise test. Carotid atherosclerosis was assessed by using B-mode ultrasonography. RESULTS: After adjustments for age, technical covariates, and cigarette smoking, VO2max had strong, inverse, and graded associations with 4-year increases in maximal intima-media thickness (IMT) (standardized regression coefficient beta = -0.120; P = 0.002), plaque height (beta = -0.140; P < 0.001), surface roughness (beta = -0.147; P < 0.001), and mean IMT (beta = -0.080; P = 0.035). These associations weakened but remained statistically significant after additional adjustment for systolic blood pressure, serum levels of apolipoprotein B, diabetes, and plasma fibrinogen levels. The increases in maximal IMT, surface roughness, and mean IMT (23%, 31%, and 100%, respectively) were larger among men in the lowest quartile of VO2max (<26.1 mL/kg per minute) than among those in the highest quartile (>36.2 mL/kg per minute). CONCLUSIONS: Good cardiorespiratory fitness is associated with slower progression of early atherosclerosis in middle-aged men. These findings are important because they emphasize that middle-aged men can be evaluated for cardiorespiratory fitness to estimate their future risk for atherosclerotic vascular diseases. Additional research is warranted to investigate a possible causal relationship between cardiorespiratory fitness and atherosclerosis.