The effect of cholecalciferol supplementation on vitamin D levels and insulin sensitivity is dose related in vitamin D-deficient HIV-1-infected patients

Objective

The aim of this study was to explore the effects of cholecalciferol supplementation on vitamin D levels, bone mineral density (BMD), body fat distribution and insulin sensitivity in vitamin D‐deficient HIV‐1‐infected patients.

Methods

Twenty vitamin D‐deficient HIV‐1‐infected patients were prospectively treated with 2000 IU cholecalciferol/day for 14 weeks, whereafter treatment was continued with half this dosage until 48 weeks. BMD, body fat distribution, 1,25‐dihydroxy vitamin D₃ (1,25(OH)₂D₃), fasting glucose, insulin, adiponectin, leptin, interleukin (IL)‐6 and tumour necrosis factor (TNF)‐α were measured at baseline, and at 24 and 48 weeks. Parathyroid hormone (PTH), 25‐hydroxy vitamin D₃ [25(OH)D₃], cholesterol and triglycerides were measured at baseline, and at 12, 24 and 48 weeks.

Results

After 24 weeks, cholecalciferol supplementation significantly increased 25(OH)D₃ and 1,25(OH)₂D₃ levels and decreased PTH and insulin sensitivity. After 48 weeks, however, only 25(OH)D₃ levels remained significantly different from baseline, while the other parameter levels returned to baseline, suggesting a dose–response effect. Cholecalciferol had no effect on BMD, adipokines and triglycerides.

Conclusions

The effect of cholecalciferol treatment in this cohort appears to be dose dependent. Cholecalciferol dosages of ≥2000 IU are necessary to achieve 1,25(OH)₂D₃ levels that significantly decrease PTH, but also negatively affect insulin sensitivity. The results of this hypothesis‐driven explorative study need to be confirmed in larger clinical trials.