Adults with osteoarthritis in the knees who take vitamin D supplements did not show an improvement in pain relief or cartilage loss, according to a new study published in JAMA. The study was a two year randomized trial consisting of patients with symptomatic knee osteoarthritis. The authors explain in background information: "Knee osteoarthritis (OA) is a common age-related musculoskeletal disorder that has significant functional impact and has considerable societal costs through work loss, early retirement, and arthroplasty...