Background fibromyalgia (FM) is a disease characterised by widespread pain, sometimes fatigue, memory problems and sleep disturbances. It has been suggested that low blood levels of vitamin D correlate with increased pain scores in patients with FM. A recent meta-analysis indicated that vitamin D may decrease pain scores in patients with FM, but with a low quality trials.

Objectives to assess the efficacy and safety of vitamin D3 in Fibromyalgia patients.

Methods a 12 week randomised, double blind, placebo-controlled trial in eighty FM patients according to the criteria of the American College of Rheumatology (ACR) 2010 who were randomised into two groups, the treatment group (n=40) received 50,000 IU of oral vitamin D3 weekly, the second group (n=40) received placebo for 12 weeks. The primary outcome was to assess the change in the Spanish version of Fibromyalgia Impact Questionnaire (S-FIQ) and Visual Analogue Scale (VAS 0–10) from baseline to week 12. Baseline serum calcium levels were measured in all subjects. Vitamin D levels were measured by chemiluminescence considering normal ranges between 30 and 100 ng/ml, insufficiency between 10 and 30 ng/ml and deficiency less than 10 ng/ml, baseline and after 12 weeks.

Results of the total, 61/80 (76%) had vitamin D insufficiency, 8/80 (10%) deficiency and 11/80 (14%) normal levels, the mean overall level of vitamin D was 21.2±9.0. There was no statistically significant reduction in S-FIQ scores in patients in the treatment group compared with placebo (47.0±23.3 vs 43.9±25.0, p=0.56) after 12 weeks; there was also no statistically significant decrease in VAS scores (6±5 vs 4±4.5, p=0.57). There was no improvement in the perception of pain when normalising vitamin D levels. No serious adverse events were reported in both groups.

Conclusions at 12 weeks of treatment with vitamin D3 50,000 IU versus placebo in patients with fibromyalgia had no statistically significant differences in the FIQ and VAS. It may be possible to find greater benefit from vitamin D if this period is extended.

References [1] Clauw DJ. Fibromyalgia: a clinical review. JAMA2014; 311(15):1547–1555.

[2] Yong WC, Sanguankeo A, Upala S. Effect of vitamin D supplementation in chronic widespread pain: a systematic review and meta-analysis. Clin Rheumatol2017Dec;36(12):2825–2833.

Disclosure of Interest None declared