Current evidence about the benefits of Vitamin D supplementation in knee osteoarthritis (OA) is contradictory. This finding disagrees with observational evidence that points to a positive impact, shows a study presented at the OARSI 2016 World Congress held in Amsterdam this month.
Comparing the effects of Vitamin D supplementation to a placebo on knee pain, knee cartilage volume, and other structural changes in symptomatic knee osteoarthritis patients with low Vitamin D could shed light on its efficacy.
In an April 2 presentation titled, “Vitamin D Supplementation for the Management of Knee Osteoarthritis: A Randomized Controlled Trial,” Changhai Ding, M.D., from the University of Tasmania in Australia, discussed whether supplementing Vitamin D over two years can lessen knee osteoarthritis symptoms.
“Vitamin D supplementation over two years did not meet either primary endpoint. Secondary analyses suggest modest benefits on knee pain, physical function, bone marrow lesions and effusion-synovitism,” the authors wrote in the abstract.
In a multicenter trial, 413 symptomatic knee osteoarthritis patients – average age 63 and 51 percent women – who also had low 25-hydroxyvitamin D (25OHD) (12.5-to-60 nmol/L) participated in a placebo-controlled study. They either received 50,000 IU Vitamin D3 (n=209) or a placebo (n= 204) for two years. Primary outcomes included a change in tibial cartilage volume on MRI and in pain levels. Secondary outcomes were knee pain, WOMAC function, cartilage defects, bone marrow lesions (BML), and joint effusion-synovitis on MRI.
Vitamin D levels did increase in the 25OHD, and the group did have less cartilage volume loss and more pain reduction, -3.44 percent and -4.23 percent and -49.9 and -35.1, respectively, even though the differences weren’t significant. After a second analysis, the 25OHD group experienced greater knee pain improvement. However, there was no significant difference in tibiofemoral cartilage defect changes or BMLs.
Fewer 25OHD participants had an increase in BMLs, and they had less increase in effusion-synovitis volume than the placebo group (0.26 ml and 2.20 ml). The 25OHD group also had a significantly higher chance of achieving a minimal clinical important improvement in total and suprapatellar effusion-synovitis.