Abstract 18311: Mechanism of Cardiovascular Benefit From Exercise in Women: Not Through Subclinical Atherosclerosis!
Introduction: Cardiorespiratory fitness (CRF) has been shown to be inversely associated with coronary heart disease (CHD) morbidity and mortality. The cardioprotective mechanism of fitness has not been well defined. The goal of this study was to assess the relationships among subclinical coronary artery calcification as a measure of atherosclerotic burden, self reported PA and measured CRF in a single large population of generally healthy women.
Methods: 6,148 women seen in a single medicine clinic between 1998 and 2007 provided self-reported measures of PA, underwent maximal treadmill exercise testing, and CAC scanning. PA was reported in MET·min per week. CRF was reported in METs derived from the maximal treadmill time. CAC was evaluated as a dichotomous variable. We used multiple logistic regression to calculate adjusted odds ratios (OR) for CAC > 0, and we applied a nonparametric trend test to the relationship between PA and CRF.
Results: The mean age was 50.9 years (±8.9). The overall prevalence of CAC was 18.8%. CAC was directly related to age, hypertension, diabetes, hyperlipidemia, and family history of CHD. Figure 1 shows mean CAC by quartile of CRF without adjustment for other covariates. When adjusted for age, the association between CAC and CRF remained significant (OR=0.995 [0.992,0.998] per MET, p<0.001) but not when adjusted for age, hypertension, diabetes, hyperlipidemia, smoking, and family history (OR=0.998 [0.995,1.001] per MET, p=0.14). CAC was not associated with PA when adjusted for age or all covariates. In this large population, we also found a direct relationship between self-reported PA and CRF (p<0.001).
Conclusions: The cardiovascular benefit of self reported PA or quantitative CRF, does not appear to be mediated by the modification of absolute calcific atherosclerotic burden in women.
- © 2011 by American Heart Association, Inc.