Observational data have suggested that vitamin D deficiency might be a common cause of otherwise unexplained musculoskeletal pain (Journal Watch Jan 9 2004). In two new studies, researchers addressed this problem.
In a cross-sectional population-based study, researchers examined the relation between vitamin D status and pain in the back, hips, knees, and feet in 958 randomly selected older adults (age,
65) in Italy. Women with low levels of 25-hydroxyvitamin D (<25 nmol/L, equivalent to 10 ng/mL) were somewhat more likely than those with higher levels to have isolated back pain without lower extremity pain (17% vs. 9%, P=0.04). However, no correlation was found between vitamin D levels and other pain patterns in women (lower extremities alone; both lower extremities and back). In men, vitamin D status did not correlate with any pattern of back or lower extremity pain.In another study, rheumatologists in Kansas City, Missouri, randomized 50 patients with diffuse musculoskeletal pain and low 25-hydroxyvitamin D levels (9–20 ng/mL) to receive ergocalciferol (vitamin D2; 50,000 IU once weekly) or placebo. At 3 months, pain scores in the two groups did not differ, despite achievement of significantly higher vitamin D levels in ergocalciferol recipients than in placebo recipients.
Comment: Taken together, these findings argue against any simple relation between diffuse pain and vitamin D deficiency. In particular, the randomized trial — although small — is a setback for the idea that vitamin D supplementation is an easy "fix" for unselected patients with diffuse pain. However, severe vitamin D deficiency clearly causes diffuse bony pain in some patients via the mechanism of osteomalacia; clinicians need better clinical criteria for identifying those patients.
— Allan S. Brett, MD
Published in Journal Watch General Medicine May 20, 2008