Abstract 8149: A Prospective Randomized Controlled Trial of the Effects of Vitamin D Supplementation on Cardiovascular Disease Risk
Background: Low vitamin D (VitD) status is associated with increased cardiovascular disease risk. Some physicians prescribe VitD supplements for risk reduction, although little data support this intervention.
Methods: This was a prospective, randomized, double-blind, placebo-controlled trial of healthy, post-menopausal women with serum 25-OH VitD concentrations >10 and <60 ng/ml. They were randomized to receive 2500 IU of VitD3 or placebo daily for 4 months. Endothelial function was evaluated by ultrasound brachial artery flow-mediated dilation (FMD). Arterial stiffness was evaluated by carotid-femoral pulse wave velocity (PWV) and aortic augmentation index (AIx) using applanation tonometry. High-sensitivity C-reactive protein (CRP) was measured by nephelometry. Changes in these parameters were compared between treatment groups using T-tests and verified by general linear models that adjusted for treatment group, VitD status, and a treatment group x VitD status interaction.
Results: The 114 subjects were mean (standard deviation) 63.9 (3.0) years old with a 25-OH VitD level of 31.3 (10.6) ng/ml. Low VitD status (<30 ng/ml) was present in 48% and was associated with higher body-mass index, systolic blood pressure, glucose, CRP, and lower FMD (all p<0.05). After 4 months, 25-OH D levels increased by 15.7 (9.3) ng/ml in the treatment group vs. -0.2 (6.1) ng/ml on placebo (p0.10). In multivariable models, there were no significant interactions between treatment group and low VitD status for changes in FMD (p=0.65), PWV (p=0.93), AIx (p=0.97), or CRP (p=0.26).
Conclusions: VitD supplementation did not improve endothelial function, vascular stiffness, or inflammation in healthy post-menopausal women. This study does not support the use of VitD supplementation to reduce cardiovascular disease risk.
- © 2011 by American Heart Association, Inc.