Abstract 20477: Cardiorespiratory Fitness, Coronary Artery Calcium and Cardiovascular Disease Events
Introduction: Both coronary calcification (CAC) and cardiorespiratory fitness (CRF) are associated with coronary heart disease. We sought to evaluate the separate contribution of each of these parameters to cardiovascular disease (CVD) events.
Methods: We studied 8505 men and 3479 women with a preventive health examination which included measurement of CRF and CAC between 1997 and 2007. There were 452 cases of incident CVD (non-fatal myocardial infarction, non-fatal atherosclerotic stroke, coronary artery bypass graft, percutaneous transluminal coronary angioplasty, stent, or CVD death) during an average follow-up of 8.3 years. CVD incidence was estimated using an accelerated failure time model adjusted for age, CRF, CAC and smoking. Age and cardiorespiratory fitness were expanded in a cubic spline basis, allowing the model to detect nonlinear accelerations associated with these covariates. In addition, a proportional hazards regression model was fit to the same outcome with the same covariates.
Results: The mean age of the cohort was 53.5 y (>90% white). Figure 1 shows estimated incidence of total cardiovascular disease in men at age 70 as a function of baseline age (separate panels for a baseline age of 35, 45, and 55), CRF and CAC. For any baseline age and level of CAC, greater CRF was associated with lesser future incidence of a CVD event. Differences between CVD incidence estimates for different levels of CAC diminished with increasing CRF with the corresponding ratios remaining relatively constant. This visual conclusion supported by proportional hazards modeling, which found no evidence for an interaction between CAC and CRF.
Conclusion: A continuous association between CRF and CVD events independent of CAC was observed with the greatest effect manifest at higher levels of CAC.
Author Disclosures: L.F. DeFina: None. N.B. Radford: None. D. Leonard: None. C.E. Barlow: None. B. Willis: None. A. Khera: None. B.D. Levine: None.
- © 2014 by American Heart Association, Inc.