Adequate
vitamin D levels may promote cardiovascular health by improving endothelial function and down-regulating
inflammation. The objective of this pilot trial was to investigate the effects of
vitamin D repletion on endothelial function and
inflammation in patients with
coronary artery disease (CAD). Using a double-blind placebo wait-list control design, 90 subjects with CAD and
vitamin D deficiency (< 20 ng/ml) were randomized 1:1 to 50,000 IU of oral
ergocalciferol or placebo weekly for 12 weeks. Endothelial function (
reactive hyperemia peripheral arterial tonometry, RH-PAT), circulating adhesion molecules, and pro-inflammatory
cytokines were measured at baseline and 12 weeks. The median increase in serum 25-vitamin D from baseline was 26 ± 17 ng/ml in the active group and 4 ± 8 ng/ml in the placebo group (between-group difference = 22 ng/ml, p < 0.001). The median within-subject change in RH-PAT score was 0.13 ± 0.73 with active treatment and -0.04 ± 0.63 with placebo (between-group difference = 0.17, p = 0.44). Within-group and between-group differences in
intercellular adhesion molecule levels were greater with placebo (between-group difference = 6 ng/ml, p = 0.048).
Vascular cell adhesion molecule levels decreased in both groups by a similar magnitude (median difference between groups = 8.5 ng/ml, p = 0.79). There was no difference between groups in magnitude of reduction in
interleukin (IL)-12 (-8.6 ng/ml, p = 0.72) and
interferon-gamma (0.52 ng/ml, p = 0.88). No significant differences in blood pressure,
e-selectin,
high-sensitivity c-reactive protein,
IL-6 or the
chemokine CXCL-10 were found with treatment. In conclusion, repleting
vitamin D levels in subjects with CAD failed to demonstrate any benefits on
surrogate markers of cardiovascular health. These results question the role of
vitamin D supplementation in modifying
cardiovascular disease.