The randomised clinical study – published in JAMA – investigated whether vitamin D supplementation was effective at reducing the symptoms and structural progression of knee osteoarthritis.
Led by Professor Timothy McAlindon from Tufts Medical Center, USA, the trial findings reveal that patients with symptomatic knee osteoarthritis who received vitamin D supplementation did not have a significant difference in primary outcome measures including knee pain and cartilage volume loss when compared to patients who received placebo.
“Vitamin D supplementation for 2 years at a dose sufficient to elevate 25-hydroxyvitamin D plasma levels to higher than 36 ng/mL, when compared with placebo, did not reduce knee pain or cartilage volume loss in patients with symptomatic knee OA,” wrote McAlindon and his colleageus.
“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 higher than 15 ng/mL,” they added.
The two-year randomised, placebo-controlled clinical trial included 146 participants with symptomatic knee OA. All participants were randomised to receive either placebo or oral cholecalciferol (2,000 IU/day) with dose escalation to increase serum levels to more than 36 ng/mL, the research team explained.
The primary measured outcomes for the study were knee pain severity (Western Ontario and McMaster Universities [WOMAC] pain scale), and cartilage volume loss measured by magnetic resonance imaging. Secondary outcomes included physical function, knee function (WOMAC function scale), cartilage thickness, bone marrow lesions, and radiographic joint space width.
“Knee pain fell by about 2 units in both groups,” said the team, who noted that the effect of treatment over time was not significant.
They added that cartilage volume decreased by around 4% in both the vitamin D and placebo groups.
Volume 309, Number 2, Pages 155-162, doi: 10.1001/jama.2012.164487
"Effect of Vitamin D Supplementation on Progression of Knee Pain and Cartilage Volume Loss in Patients With Symptomatic Osteoarthritis. A Randomized Controlled Trial"
Authors: Timothy McAlindon, DMichael LaValley, Erica Schneider, Melynn Nuite, et al