Symptomatic knee osteoarthritis occurs among 10% of men and 13% of women aged 60 years or older. Knee osteoarthritis is the 11th leading cause of global disability and siginificantly impacting the well being of people lives.. Currently there are no effective therapies for osteoarthritis. Cost-effective approaches to prevent the development and progression of osteoarthritis are needed. Vitamin D can reduce bone turnover and cartilage degradation, thus potentially a candidate treatment for preventing the development and progression of knee osteoarthritis. Observational studies also point in that direction, at the same time there are also conflicting results and observations. To clarify the effect of vitamin D a team of the University of Tasmania, Australia evaluated the effects of 2 years of vitamin supplementation vs placebo on knee pain and knee cartilage volume in patients with symptomatic knee osteoarthritis combined with low vitamin D levels. Effects on the knee structural abnormalities, including cartilage defects and bone marrow lesions, were also assessed.
A multicenter randomized, double-blind, placebo-controlled clinical trial in Tasmania and Victoria, Australia was setup. Participants with symptomatic knee osteoarthritis and low 25-hydroxyvitamin D (12.5-60 nmol/L) were enrolled from June 2010 to December 2011. The trial was completed in December 2013. The analyses included among others MRI scans and WOMAC pain scale scoring.
Of 413 enrolled participants (mean age, 63.2 years; 50% women), 340 (82.3%) completed the study. The level of 25-hydroxyvitamin D increased more in the vitamin D group (40.6 nmol/L) than in the placebo group (6.7 nmol/L) over 2 years. There were however no significant differences in annual change of cartilage volume or pain score. Neither were there significant differences in change of cartilage defects or change in bone marrow lesions. Adverse events occurred in 56 participants in the vitamin D group and in 37 participants in the placebo group.
Considering that even among study participants with low vitamin D, supplementation did not slow cartilage loss or improve WOMAC-assessed pain the data suggests a lack of evidence to support vitamin D supplementation for slowing disease progression or structural change in knee osteoarthritis. Overall the findings do not support the use of vitamin D supplementation for prevention or treatment of knee osteoarthritis.
The report of the study can be found here.