medwireNews: Twelve weeks of high-dose vitamin D supplementation does not improve pain levels for women with fibromyalgia, research suggests.
In the double-blind study, published in Clinical Rheumatology, 80 women (mean age 50 years) with fibromyalgia were randomly assigned to receive vitamin D3 (cholecalciferol) 50,000 IU or placebo weekly for 12 weeks.
At baseline, vitamin D levels and pain according to the Fibromyalgia Impact Questionnaire (FIQ) or the pain VAS were similar between the two groups.
After 12 weeks, vitamin D levels had increased in both groups. Levels rose significantly more in the vitamin D group than the placebo group, from a mean of 20.10 ng/mL at baseline to a mean of 51.13 ng/mL versus an increase from 12.60 to 20.80 ng/mL.
However, increased vitamin D levels did not correlate with a reduction in pain over the 12-week period. The patients had comparable levels of pain at 12 weeks irrespective of whether they received vitamin D supplementation or placebo, with mean FIQ scores of 46.28 and 44.54 points, respectively, and mean pain VAS scores of 4.90 and 5.19 points. And there was little change from the baseline FIQ scores of 64.51 and 61.88 points, respectively, and the pain VAS scores of 6.00 points in both groups.
These findings “support the concept that vitamin D is not useful for pain control, at least for the period used in this study,” emphasize David Vega-Morales and fellow investigators from the Universidad Autónoma de Nuevo León in Monterrey, Mexico.
They add that no serious adverse events occurred in either the vitamin D or placebo group and of the “minor” adverse events that occurred, dizziness (5.0 vs 2.5%, respectively) and fatigue (2.5 vs 5.0%) were among the most common.
Vega-Morales et al acknowledge that, currently, “there are conflicting results about the effect of vitamin D in pain and symptom control, and there is no clear consensus as to the role of supplementation in the management of fibromyalgia.”
And while their findings suggest that vitamin D supplementation might not be involved in pain management, the researchers say they “cannot rule out that a more lasting and prolonged correction of vitamin D levels could induce biochemical changes that lead to a better evolution of other symptoms associated with fibromyalgia other than the pain.”
The researchers therefore advise “that adequate vitamin D supplementation and moderate sun exposure should be encouraged, given its benefits already demonstrated in other pathologies, even though we could not demonstrate its benefit in improving pain and in the FIQ.”
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