The effect of vitamin D supplementation on knee osteoarthritis: A meta-analysis of randomized controlled trials

Gao XR, Chen YS, Deng W · International Journal of Surgery

Small improvements in WOMAC pain and function, larger with >2000 IU/day, but NO effect on tibial cartilage volume loss — symptomatic signal without structural protection.

Population

Knee OA patients across 4 RCTs

Intervention

Oral vitamin D supplementation (various doses)

Comparator

Placebo

Limitations

Only 4 trials; symptomatic effect sizes are below accepted clinically-important thresholds; heterogeneous dosing.