The efficacy of vitamin D in treatment of fibromyalgia: a meta-analysis of randomized controlled studies and systematic review

Background and aims Recent studies have found potential benefits of vitamin D in relieving pain, and the results from randomized controlled trials of vitamin D for fibromyalgia have been promising. We conducted a comprehensive systematic review and meta-analysis to evaluate the efficacy of vitamin D for treating fibromyalgia. Research design and methods PubMed, Web of Science, Embase, and Cochrane Library databases were systematically searched for English-language articles. Based on the inclusion and exclusion criteria, we selected only randomized controlled studies that reported vitamin D versus placebo-controlled cure for fibromyalgia. After extracting valid data, a meta-analysis was performed using Stata 12.0. The major outcome in the pooled analysis was the Fibromyalgia Impact Questionnaire and Visual Analogue Scale (VAS) changes. Results Five studies including 315 participants were identified. These studies found that vitamin D was effective in reducing Fibromyalgia Impact Questionnaire scores compared with those of the control group, with significant differences (weighted mean difference = -7.82, 95% confidence interval: -12.05 to -3.59, P < 0.001). However, there was no statistical difference in VAS between the two groups (weighted mean difference = -0.60, 95% confidence interval: -1.38 to 0.17, P > 0.05). Conclusions Vitamin D supplementation may be an effective fibromyalgia therapeutic approach.