WEDNESDAY, Nov. 24, 2004 (HealthDayNews) -- Glucosamine, the popular dietary supplement long promoted as a natural remedy for osteoarthritis, offers no long-term benefit, a small Canadian study suggests.
Supporters of the supplement, however, say that the study is far from the last word on the subject.
And everyone is awaiting the results of a larger, U.S. government trial.
The smaller study, published in a recent issue of the journal Arthritis & Rheumatism, tracked 137 people who took glucosamine and had had at least moderate improvement in knee pain. British Columbia researchers randomly assigned half to continue on glucosamine, up to 1,500 milligrams a day, and the other half to take placebo pills.
They followed them for six months to determine if the disease flared; if there was a flare-up in the interim, the patients stopped taking the supplement.
The glucosamine didn't help, the researchers found. "Our conclusion is that, certainly, maintenance treatment with glucosamine is of no benefit," said Dr. Jolanda Cibere, a research scientist at the Arthritis Research Centre of Canada in Vancouver and the lead author.
Those on glucosamine didn't report less pain or less time for the disease to flare up again. Disease flare was seen in 42 percent of the placebo patients and 45 percent of those on glucosamine. The use of painkilling drugs was similar in the two groups.
But the study sparked disagreement, with some saying it is flawed. And many are awaiting the results of a large clinical trial, sponsored by the U.S. National Center for Complementary and Alternative Medicine (NCCAM), of glucosamine and another supplement, chondroitin. Data from the study, including more than 1,500 subjects, is currently being analyzed so that the results can be released.
A second NCCAM study of glucosamine and chondroitin for arthritis, which focuses on the absorption and distribution of the two supplements in the body, is now recruiting patients. The NCCAM is a division of the U.S. National Institutes of Health.
About 21 million adults in the U.S. have osteoarthritis, the "wear-and-tear" form of the disease that increases with age, according to the NCCAM. Both glucosamine and chondroitin are natural substances that are found in and around cartilage cells, and are believed to help in the repair and maintenance of the cartilage.
While the medical literature has produced mixed results on the value of glucosamine, most recent studies show a benefit, said Dr. Kevin Stone, an orthopaedic surgeon and chairman of the Stone Foundation for Sports Medicine and Arthritis Research in San Francisco.
"We recommend it for all our patients, both athletes and those with arthritis," said Stone. "For those with arthritis, many of our patients have given up using nonsteroidal anti-inflammatories because glucosamine has been adequate for them." Stone prescribes 1,500 milligrams a day, taken all at once.
When some of his patients complained about the "horse pill" size of glucosamine supplements, Stone founded Joint Juice, a company that sells glucosamine in liquid form.
Stone called the British Columbia study flawed. Among the problems, he said, was to do it as a "discontinuation" study -- that is, to have some patients stop taking the supplement.
"This discontinuation study method has never been used in osteoarthritis before," Stone said. "It's completely invalidated."
But Cibere disagreed, saying the method makes sense. In her study, all patients had reported improvement in knee pain when they began on glucosamine, and her point was to determine if the therapy worked long-term or if the disease flared up after they stayed on the therapy.
To learn more about glucosamine and chondroitin sulfate, visit the American Academy of Orthopaedic Surgeons .