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Dutch Study Shows Popular Supplement No Better Than Placebo; Industry Disagrees
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Reviewed By Brunilda Nazario, MD
The popular supplement glucosamine, used by many arthritis sufferers, was found to be no better than placebo pills for relieving the pain of hip osteoarthritis or increasing the ability to do everyday activities, according to a new study from the Netherlands.
"In our study, there was not much room for doubt," says Rianne Rozendaal, MSc, the study's lead researcher.
"The differences between the glucosamine and placebo group were all very small," says Rozendaal, a researcher at the Erasmus Medical Center in Rotterdam, Netherlands.
But representatives of the supplement industry disagree, with one manufacturer saying the researchers may have focused on people too early in the arthritic process.
Glucosamine and Arthritis
An estimated 21 million Americans have osteoarthritis (or "wear-and-tear" arthritis) affecting the hips, knees, and other joints, according to the Arthritis Foundation. The condition is marked by the breakdown of the joint's cartilage, which cushions the bone endings and allows you to move easily.
A substance found naturally in healthy joint cartilage, glucosamine stimulates the formation and repair of cartilage, according to the American Academy of Orthopaedic Surgeons, but over-the-counter supplements come from animal or plant sources. Studies of the effectiveness of glucosamine have yielded mixed findings.
Study Details: Glucosamine and Arthritis
Rozendaal and her team assigned 222 patients, all with hip osteoarthritis that was generally termed mild, to take either 1,500 milligrams of glucosamine sulfate or a placebo pill every day for two years. On average, patients were in their early 60s.
About equal numbers in each group underwent total hip replacement surgery during the study. The researchers evaluated the patients at three, 12, and 24 months after they began the treatments, collecting information about the patients' pain levels and how well they could perform everyday activities.
X-rays were taken to measure the joint space in the hip. As osteoarthritis gets worse, this joint space gets narrower.
Glucosamine and Arthritis: No Hip Help
At the study's end, the pain scores of those who took the supplement didn't differ much from those who took the placebo, Rozendaal says. On the scale used, "the pain scores range from 0 to 100," she explains in an email interview, "where 0 equals no pain and 100 equals [the] most severe pain."
The average difference between groups in pain scores was a decline of just 1.5 points, she says. To be statistically significant, there would have to have been a difference of at least 10 points, she says.
"Our trial does not suggest an effect of glucosamine for hip osteoarthritis," she adds.
No differences were found between groups in the joint space narrowing, either, Rozendaal says. The study is published in the Annals of Internal Medicine.
Another View: Jury Is Out
In an editorial accompanying the study, authors from another Dutch medical center note that "the study is indeed negative" but caution that the results apply only to hip osteoarthritis. They conclude that the role of glucosamine in arthritis treatment is still under debate.
They also note that when the authors looked at a subset of people with osteoarthritis in other parts of their bodies, they found a small trend toward pain reduction and improved functioning, but the change wasn't significant.
A better group of patients to study would have been those with more severe arthritis because the disease progresses more rapidly then, and it might have been easier to see any effect of the supplement, wrote Johannes W.J. Bijlsma, MD, PhD, and Floris P.J.G. Lafeber, PhD, of the University Medical Center Utrecht.
"What they did was study people too early in the arthritic process," agrees Luke Bucci, PhD, vice president of research at Schiff Nutrition International in Salt Lake City, which makes a glucosamine supplement.
He says that "they were starting to see some small advantages for the glucosamine group."
A Clinician's View
The study findings don't surprise Jay Mabrey, MD, chief of orthopedics at Baylor University Medical Center in Dallas. Nor does he expect this study to be the last word on the supplement.
"There are people who really believe in this and I am sure they will proceed with their own studies," Mabrey says.
His advice about its use? "I don't discourage it, and that's different from encouraging [its use]," he says. "It seems about half my patients [who use the supplement] report some type of relief, but that could very well be placebo effect." When patients ask, he tells them: "So far the studies don't show any definite advantage." But "as far as we know," it doesn't appear to do harm, he says.
SOURCES: Rozendaal, R. Annals of Internal Medicine, Feb. 19, 2008, vol 148: pp 268-277. Bijlsma, J. Annals of Internal Medicine, Feb. 19, 2008. vol 148: pp 315-316. Rianne Rozendaal, MSc, researcher, Erasmus Medical Center, Rotterdam, Netherlands. Luke Bucci, PhD, vice president of research, Schiff Nutrition International, Salt Lake City. Jay Mabrey, MD, chief of orthopedics, Baylor University Medical Center, Dallas. Arthritis Foundation web site: "Osteoarthritis: What is it?" American Academy of Orthopaedic Surgeons web site: "Glucosamine and Chondroitin Sulfate."
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