No Benefit of Vitamin D Supplementation for Knee Osteoarthritis

Disruption of normal bone architecture in knee osteoarthritis (OA), combined with certain epidemiologic observations, led investigators to study the potential benefit of vitamin D supplementation in 146 adults with knee OA (mean age, 63; mean baseline 25-hydroxyvitamin D [25(OH)D] level, 22 ng/mL; most with knee malalignment and moderate-to-severe joint space narrowing and sclerosis). Participants were randomized to cholecalciferol (vitamin D₃; 2000 IU daily) or placebo. Dosages in the intervention group were adjusted to achieve 25(OH)D levels >36 ng/mL; doses as high as 6000–8000 IU daily were required in several participants.

More than 80% of each group completed the 2-year trial, at which time knee pain was diminished slightly in both gro…