Does vitamin D supplementation alleviate chronic nonspecific musculoskeletal pain? A systematic review and meta-analysis.

Chronic nonspecific musculoskeletal pain (CNMP) is an idiopathic condition often seen in general practice and rheumatology clinics, the aetiology of which may include vitamin D deficiency. The objective of the present study is to evaluate the effectiveness of vitamin D supplementation in the management of CNMP through a systematic review and meta-analysis. According to PRISMA guidelines, PubMed, Embase, Web of Science, Cochrane and Scopus electronic databases were searched for randomised controlled trials comparing vitamin D supplementation to a control or placebo in CNMP patients; the search was not limited by language or date. Meta-analysis was performed using the mean and standardised mean difference which was computed with 95 % confidence intervals, and overall effect size was calculated. Both fixed and random effects models were used in meta-analysis to account for heterogeneity in the studies. The initial search identified 107 studies, of which 10 were potentially relevant, with 7 studies excluded because they did not meet selection criteria. Three studies were included in the meta-analysis. We found no effect of vitamin D supplementation (standardised mean difference (SMD) 0.004; 95 % confidence interval (CI) -0.248 to 0.256) on pain in CNMP patients. Forest plot is used to present the results from meta-analysis. Contrary to a widespread clinical view, there is a moderate level of evidence that vitamin D supplementation is not helpful for treating CNMP patients.