Chronic widespread pain (CWP), including fibromyalgia (FM), is prevalent in the general population, with estimates ranging from 10-18%. As vitamin D has been proposed to be an associated factor in CWP, this meta-analysis was designed to better understand this relationship.

Medical databases were reviewed for randomized, controlled trials involving patients with CWP, FM and vitamin D supplementation. From those studies were extracted diagnoses, serum vitamin D levels, vitamin D dosing and the results of clinical outcome measures. The primary outcome variables of the meta-analysis were differences in VAS pain scores, Fibromyalgia Impact Questionnaire (FIQ) scores or Discomfort Behavior Scale (DBS) scores between the intervention and the placebo groups.

From the literature review, six randomized, controlled trials were identified and were included in this analysis. The pooled results revealed that patients with CWP who received vitamin D treatment had significantly lower pain scores than those who received a placebo. No significant relationship was found between changes in blood levels of vitamin D and pain scores.

This study of patients with chronic, widespread pain found that vitamin D supplementation can decrease pain scores, independent of changes in blood levels of vitamin D.