Abstract 019: Association between Vitamin D and Cardiovascular Events: The Heart and Soul Study
Background: A growing body of evidence indicates that vitamin D deficiency is associated with adverse cardiovascular (CV) outcomes. It is unclear whether vitamin D deficiency is simply a marker of poor health habits or whether this association is mediated by biological changes that may increase risk of CV events.
Methods: We measured 25-hydroxy vitamin D levels in 947 participants with stable coronary heart disease (CHD) from the San Francisco Bay Area in 2000-02, and followed them prospectively for CV events (heart failure, myocardial infarction, stroke or CV death). We used cubic splines to model the association between 25-OH D and CV events in order to determine appropriate cutpoints. We used Cox models to evaluate the association of 25-OH D levels with subsequent CV events. We then examined the extent to which the association was attenuated by adjustment for poor health habits (physical activity, smoking, multivitamin
use) and potential biologic mediators (blood pressure, lipids, glycohemoglobin, C-reactive protein and parathyroid hormone).
Results: During a mean follow-up of 7.4 years, 30.5% of subjects (301/947) experienced an adverse CV event. The association between 25-OH D and CV events was nonlinear, with a sharp increase in risk at levels <20 ng/mL, and the lowest risk in subjects with levels of 30 ng/mL. Subjects with 25-OH D <20 ng/mL had a 56% greater rate of CV events than those with 25-OH D levels ≥30 ng/mL, and this association persisted after adjustment for comorbid conditions (HR 1.52, 95% CI 1.14-2.02). Further adjustment for poor health behaviors moderately attenuated the association (HR 1.30; 95% CI 0.96-1.76), and the association was no longer present after adjustment for potential biological mediators (HR 1.02, 95% CI 0.73-1.42; Table).
Conclusions: Vitamin D deficiency is associated with adverse CV outcomes in outpatients with stable CHD. This relationship appears to be partly due to poor health habits but mostly explained by changes in biological mediators associated with vitamin D.
- © 2013 by American Heart Association, Inc.