THE EFFECT OF VITAMIN D SUPPLEMENTATION ON THE ANDROGENIC PROFILE IN MEN: A SYSTEMATIC REVIEW AND META-ANALYSIS OF CLINICAL TRIALS

Background and Aim: The aimed of this systematic review and meta-analysis was to evaluate the effect of vitamin D supplementation on total testosterone (TT) and sex hormone-binding globulin (SHBG) in men.Methods: We searched the PubMed, Scopus and Web of Science for randomized, controlled trials of vitamin D supplementation in men ≥ 18 years old up to June 2018, without language restrictions. Meta-analysis was based on a random-effect model. The systematic review was registered as CRD42018094498.Results: We identified 3149 article, which 11 studies met inclusion criteria. Vitamin D3 daily dose equivalents ranged from 600-4000 per day to 60,000 IU per week; duration was 6 weeks to 36 months. In general, vitamin D supplementation had no significant effect on total testosterone (MD = 0.25, 95% CI: -0.17 - 0.67, P = 0.177) and marginal increase in SHBG (MD = 2.43, 95% CI: -0.04 - 4.91, P = 0.054). Subgroup analysis conducted with duration of prescription, type (daily or weekly) and dosing frequency showed that vitamin D did not significantly effect on total testosterone.Conclusion: We found a slight increase in SHBG and no effect on total testosterone, but further large-scale RCTs are required to further evaluate the effects of vitamin D supplementation on androgen in men.

Keywords:

vitamin D , Total testosterone , SHBG , Men