Vitamin D Supplementation and Endothelial Function in Vitamin D Deficient HIV-Infected Patients: A Randomized Placebo-Controlled Trial
What this study found
Vitamin D3 did not improve endothelial function in this population. Flow-mediated dilation changed by 0.55% [IQR -1.05 to 2.13] with vitamin D versus 0.29% [IQR -1.61 to 1.77] with placebo (P=0.748). The intervention did increase serum 25(OH)D by 5.0 ng/ml [IQR -0.9 to 7.4] versus -1.9 ng/ml [IQR -4.0 to 0.1] with placebo (P=0.003), but it also increased insulin resistance, with HOMA-IR >3.0 in 53% versus 20% at follow-up (P=0.033). Total cholesterol and non-HDL cholesterol decreased, IL-6 changed significantly (P=0.010), and no grade 2 or higher adverse events were reported.
- Study & population
- Randomized, placebo-controlled trial in vitamin D-deficient HIV-infected adults on stable antiretroviral therapy with durable virological suppression.
- Intervention
- Vitamin D3 (cholecalciferol) 4,000 IU daily, given orally as two 2,000 IU capsules, for 12 weeks versus placebo.
- Key limitation
- Small, single-center study with a short 12-week intervention period, which limits power and generalizability.
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Open PDFOriginal abstract
Background Studies suggest that vitamin D deficiency is a risk factor for cardiovascular disease and diabetes. Vitamin D deficiency is prevalent in HIV patients but the effect of vitamin D supplementation on cardiovascular risk in this population is unknown. Methods We conducted a randomized, double-blind, placebo-controlled trial among 45 HIV-infected adults in Cleveland (OH, USA) on stable antiretroviral therapy with durable virological suppression and a baseline serum 25-hydroxyvitamin D level of ≤20 ng/ml. Participants were randomized 2:1 to vitamin D3 4,000 IU daily or placebo for 12 weeks. The primary outcome was a change in flow-mediated brachial artery dilation (FMD). Results Baseline demographics were similar except for age (vitamin D versus placebo, mean ±sd 47 ±8 versus 40 ±10 years; P=0.009). Both groups had reduced FMD at baseline (median values 2.9% [IQR 1.6–4.8] for vitamin D versus 2.5% [IQR 1.7–6.4] for placebo; P=0.819). Despite an increase in the concentration of serum 25-hydroxyvitamin D from baseline to 12 weeks (5.0 ng/ ml [IQR -0.9–7.4] versus -1.9 ng/ml [IQR -4.0–0.1] for vitamin D versus placebo, respectively; P=0.003), there was no difference in FMD change (0.55% [IQR -1.05– 2.13] versus 0.29% [IQR -1.61–1.77]; P=0.748). Vitamin D supplementation was associated with a decrease in total and non-high-density lipoprotein cholesterol, and an increase in indices of insulin resistance. Conclusions Among HIV-infected individuals with vitamin D deficiency, supplementation with 4,000 IU vitamin D3 daily for 12 weeks modestly improved vitamin D status and cholesterol but worsened insulin resistance without change in endothelial function. The mechanisms of resistance to standard doses of vitamin D and the complex role of vitamin D in glucose metabolism in this population require further investigation.