Consumers who take an expensive daily dietary supplement to slow cartilage loss may be wasting their money. In a two-year study led by University of Utah doctors, the dietary supplements glucosamine and chondroitin sulfate performed no better than placebo in slowing the rate of cartilage loss in the knees of osteoarthritis patients.
This was an ancillary study concurrently conducted on a subset of the patients who were enrolled in the prospective, randomized GAIT (Glucosamine/chondroitin Arthritis Intervention Trial). The primary objective of this ancillary study was to investigate whether these dietary supplements could diminish the structural damage of osteoarthritis.
The results, published in the October issue of Arthritis & Rheumatism, show none of the agents had a clinically significant effect on slowing the rate of joint space width loss--the distance between the ends of joint bones as shown by X-ray.
However, in line with other recent studies, the researchers observed that all the study's participants had a slower rate of joint space width loss than expected, making it more difficult to detect the effects of the dietary supplements and other agents used in the study.
"At two years, no treatment achieved what was predefined to be a clinically important reduction in joint space width loss," said Allen D. Sawitzke, M.D., associate professor of internal medicine at the University of Utah School of Medicine and the lead investigator. "While we found a trend toward improvement among those with moderate osteoarthritis of the knee in those taking glucosamine, we were not able to draw any definitive conclusions."
More than 21 million Americans have osteoarthritis, with many taking glucosamine and chondroitin sulfate, separately or in combination, to relieve pain. The original GAIT, led by University of Utah rheumatologist Daniel O. Clegg, M.D., professor of internal medicine, was a multicenter, randomized, national clinical trial that studied whether these dietary supplements provided significant pain relief to people with osteoarthritis in the knees.
GAIT found that the supplements produced no more pain relief than placebo, although a subset of the original GAIT participants with moderate to severe osteoarthritis knee pain appeared to receive significant pain relief when they took a combination of glucosamine and chondroitin sulfate.
