Popular supplement doesn't prevent loss of cartilage in knee, study finds
TUESDAY, Oct. 20 (HealthDay News) -- Glucosamine takes a hit in a new study that finds it doesn't prevent cartilage loss in people with osteoarthritis of the knee, University of Pittsburgh researchers report.
Many arthritis sufferers take glucosamine supplements in an attempt to reduce pain or to slow the disease's progression, but previous studies have questioned its effectiveness.
In this new study, Dr. C. Kent Kwoh, professor of medicine and epidemiology in the university's division of rheumatology and clinical immunology, had 201 people with mild to moderate knee pain randomly assigned to receive glucosamine or placebo. The study participants underwent MRI and X-ray screening at the start of the trial and 24 weeks later.
Kwoh's group found the same progression of cartilage damage in those who received glucosamine as in those who received placebo. Worsening bone lesions were also the same for both groups, and there was no difference in cartilage synthesis between the groups, the researchers noted.
The result of the study is "not surprising," said Dr. Carlos Lozada, an associate professor of rheumatology and immunology at the University of Miami Leonard M. Miller School of Medicine, who was familiar with the study.
"The larger studies that have been done to date looking at cartilage preservation using glucosamine have essentially been negative," Lozada said.
These new results were scheduled to be presented Tuesday at the American College of Rheumatology Annual Scientific Meeting, held Oct. 17 to 21 in Philadelphia.
"In this six-month study using state-of-the-art MR imaging, we were not able to demonstrate any benefit of glucosamine on the prevention of worsening joint damage in individuals with mild to moderate knee pain," Kwoh said in a prepared statement.
Osteoarthritis, the most common joint disease among middle-aged and older people, results from progressive damage to the joint cartilage. The disease causes fluid accumulation, bony overgrowth, and loosening and weakness of muscles and tendons, which can limit movement and cause pain and swelling.
Weight-bearing joints -- the knees, hips and spine -- are most often affected. Osteoarthritis in the knee and hip can result in chronic pain or discomfort while standing or walking.
Glucosamine, a natural compound, is part of healthy cartilage. Another recent study found no evidence that glucosamine supplements had any effect on pain or function, and no improvement was noted in the X-rays of people taking it.
Despite these results, Lozada thinks glucosamine might have a role in managing pain. There are studies suggesting that that is possible -- but the studies have been conflicting.
"For most doctors, glucosamine is not a standard recommendation for treating osteoarthritis," Lozada said. "It is something you might mention to a patient who is motivated to try nutritional supplements," he said.
If a patient has tried other painkillers, weight loss and exercise, and these haven't worked, then the doctor might mention trying glucosamine, Lozada said. "But it is in no way something every single patient should try," he said. "We really don't have the data to support that."
For more information on osteoarthritis, visit the U.S. National Library of Medicine.
SOURCES: Carlos Lozada, M.D., associate professor, rheumatology and immunology, University of Miami Leonard M. Miller School of Medicine; Oct. 19, 2009, news release, American College of Rheumatology
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