Research

Vitamin D and osteoarthritis of the knee

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The literature appears to be full of references to vitamin D, with large numbers of patients admitted for fragility fractures found to have depleted vitamin D levels. There are plenty of studies demonstrating its effect on combatting osteomalacia and osteoporosis. However, although low serum vitamin D levels have been linked to radiological progression of osteoarthritis (OA), there are few studies, and no large scale RCTs, to test the hypothesis that vitamin D supplementation may benefit these patients. A study team based in Oxford (UK)³ set out to establish if vitamin D may indeed have a role to play in the treatment of osteoarthritis. Using the knee as a model, the VIDEO study reports three-year outcomes of a double-blinded randomised controlled trial reporting the outcomes of 474 patients, all with radiographic knee OA. Patients were randomised to either 800 IU of cholecalciferol or placebo daily. Outcomes were assessed using the rate of joint space narrowing with a range of secondary outcomes including Kellgren-Lawrence grade, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, function, stiffness and the ‘up and go’ test. To cut a long story short, there were no differences in any primary or secondary outcome levels other than serum vitamin D levels. This study really does put to bed the suggestion that vitamin D levels may be useful in the treatment of OA of the knee.