(HealthDay News)  For adults with symptomatic knee osteoarthritis (OA), vitamin D supplementation for two years does not reduce knee pain or cartilage volume loss compared to placebo, according to a study published in the Jan. 9 issue of the Journal of the American Medical Association.

Timothy McAlindon, DM, MPH, of the Tufts Medical Center in Boston, and colleagues conducted a two-year placebo-controlled trial involving 146 participants (62.4 years; 61% women) with symptomatic knee OA who were randomized to receive placebo or oral cholecalciferol 2,000IU/day with dose escalation to raise serum levels to >36ng/mL.

The researchers found that the mean serum 25-hydroxyvitamin D levels increased by a mean 16.1ng/mL and 2.1ng/mL in the treatment and placebo groups, respectively. Compared with the placebo group, the treatment group experienced significantly worse baseline knee pain and function. There was no significant difference at any time in the decrease in knee pain (mean, −2.31 in the treatment group vs. −1.46 in the placebo group). In both groups, the percentage of cartilage volume decreased by the same extent (mean, −4.3 and −4.25, respectively).

“In summary, the results of this trial together with recent observational data indicate that vitamin D does not have a major effect on knee OA symptoms or progression among individuals who have a 25-hydroxyvitamin D level >15ng/mL,” the authors write.

Several authors disclosed financial ties to the pharmaceutical industry.

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