from Essential Evidence April 09
Clinical question
Is vitamin D supplementation effective in the treatment of chronic pain in patients with normal serum levels or low serum levels?
Bottom line
The currently available evidence does not demonstrate a relationship between low vitamin D levels and chronic pain. Like many interventions in medicine, unmasked trials and case series show a benefit of vitamin D supplementation that is not subsequently verified by masked, controlled trials. Level of Evidence = 3a
Reference
Straube S, Andrew Moore R, Derry S, McQuay HJ. Vitamin D and chronic pain. Pain 2009;141(1-2):10-13.
Study design: Systematic review
Setting: Other
Synopsis
Though lacking a plausible mechanism, vitamin D deficiency has been associated with pain due to osteomalacia and other causes of chronic pain. The researchers conducting this less-than-rigorous systematic review attempted to summarize the support for this theory. They searched Medline (but no other databases) for research on the relationship between vitamin D and pain, as well as bibliographies of review articles, including trials in any language. They give no other details on the conduct of their research protocol. Five randomized double-blind trials assessed the effectiveness of vitamin D treatment in a total of 229 patients; only 1 study of 22 patients found a benefit of vitamin D supplementation on "pain-mobility scores" in postmenopausal women with backache. Only 1 study enrolled patients with pain and vitamin D deficiency, and this study showed no benefit following 3 months of treatment. Lower quality studies — case series — showed a benefit of treatment. Low vitamin D levels were not more common in patients with chronic pain than in control populations, regardless of latitude (and likely sunlight exposure).
Copyright© 2009 John Wiley & Sons, Inc.