Abstract 10321: Association of 25(OH) Vitamin D Levels and All-cause and CVD Mortality in the Women's Health Initiative
Background: Prospective epidemiologic data relating serum levels of 25(OH) Vitamin D to mortality are limited. Objectives: To determine if 25(OH) Vitamin D levels are prospectively and independently associated with cardiovascular disease (CVD) and all-cause mortality in post-menopausal women.
Methods: Within the Women's Health Initiative observational study and clinical trial control groups, 1829 post-menopausal women who had baseline serum 25(OH) Vitamin D levels measured were followed for over 10 years for CVD death and all-cause mortality. Using inverse probability weighting to account for non-random selection of the sub-cohort, proportional hazards models were performed evaluating quartiles of season standardized 25(OH) Vitamin D levels adjusting for age, ethnicity, clinical trial indicator, smoking status, history of hypertension, systolic blood pressure, history of treated diabetes, history of CVD, history of fracture on or after age 55, and history of cancer; waist circumference, and weekly alcohol consumption. Sequential model building was performed to evaluate the additive effects of confounders on the association with all-cause mortality.
Results: Of the 1829 women, 224 deaths occurred, with 79 coming from CVD. Quartiles of 25(OH) Vitamin D in nmol/L were Q1 (3.25–36.50), Q2 (36.5–49.95), Q3(49.96–65.38), Q4(65.38–146.67). BMI differed by quartiles (Q1-28.5 (9.9),Q2-25.2(12.9),Q3-22.4(13.2), Q4-21.1(11.8). Age, race, trial indicator adjusted HR were significant for Q4 vs. Q1 for both all-cause (HR 1.62, 95% CI 1.1,2.36) and CVD mortality (HR 1.92, 95% CI 1.03,3.58), but the risk was attenuated to non-significance once adjusted for all confounders (HR 1.27, 95%CI 0.81,1.99) and HR 1.30, 95% CI 0.83,2.03). Sequential model building revealed that waist circumference had the greatest attenuation of the association between 25(OH) vitamin D levels and all-cause mortality (ΔHR =0.29, 17.9%).
Conclusions: Low levels of 25(OH) Vitamin D are associated increased risk of all-cause and CVD mortality but this risk is attenuated once adjusting for established CVD risk factors with waist circumference being the most prominent.This research has received full or partial funding support from the American Heart Association.
- © 2010 by American Heart Association, Inc.