Over the past decade, the dietary supplements glucosamine and chondroitin have been widely promoted and used to relieve the pain associated with knee OA. In addition, some studies suggest that glucosamine and chondroitin may reduce the loss of joint cartilage that occurs with the disease. The Glucosamine/chondroitin Arthritis Intervention Trial (GAIT) – the most comprehensive clinical trial of these supplements to date – is a landmark study conducted to better define the role of glucosamine and chondroitin in the treatment of knee OA. Results from GAIT were published in the New England Journal of Medicine in February 2006.

Funded by the National Institutes of Health and conducted at 16 U.S. rheumatology centers, GAIT was designed to rigorously evaluate the efficacy and safety of these agents alone and in combination when taken over a 24-week period. The study measured the effects of taking glucosamine alone, chondroitin alone, a glucosamine-chondroitin combination or celecoxib (Celebrex) alone against placebo in 1,258 people with mild or moderate-to-severe pain from knee OA.

The scientists found that the more severe the pain, the better the response. People with moderate-to-severe knee OA pain who took the glucosamine-chondroitin dietary supplement experienced 25 percent greater pain relief than those taking either supplement alone. The glucosamine-chondroitin combination showed no greater effectiveness than placebo in people with mild knee OA pain, however.

GAIT is ongoing and the findings of the portion of the trial examining the effect of glucosamine and chondroitin on cartilage loss within the knee should be available in the near future. There is speculation that the supplements may alter the course of the disease even if they do not relieve mild OA pain.