Popular supplement may fight osteoarthritis
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November 15, 1999
Web posted at: 11:36 AM EST (1636 GMT)
By Sarah Yang
A new study in Europe has found that glucosamine sulfate may slow joint damage and ease symptoms for patients suffering from osteoarthritis of the knee, lending scientific support to a dietary supplement that has become increasingly popular in the United States.
Clinicians at a research center in the University of Liege in Belgium found that patients with the condition who took 1,500 milligrams of glucosamine sulfate every day for three years reported significantly less pain, less restriction of movement and less lost joint space -- an indication of disease progression -- than people who took placebos.
Gathering scientific weight
Many studies in the past have found glucosamine sulfate to offer effective pain relief for osteoarthritis. But scientists have criticized those studies for being too short, having too few patients or being poorly controlled.
"We know we can control symptoms for two to three months, but osteoarthritis is a chronic disease" lasting years or even decades, said Lucio Rovati, M.D., coauthor of the study and chief of the clinical pharmacology department at Rotta Research Laboratorium in Italy. Rotta, a manufacturer of glucosamine sulfate, funded the study. "The real question is long-term. This is the first trial that's large enough and that's long-term showing efficacy."
Researchers randomly assigned more than 200 patients to two groups in the double-blind study. Patients reported their symptoms every four months, and X-rays were taken at the start of the study and one and three years after enrollment.
For the 139 patients who stayed in the study for all three years, the space between the knee joints decreased an average of 0.31 mm in the placebo group, while those taking glucosamine sulfate didn't, on average, lose any joint space.
The findings, announced Monday at the annual meeting of the American College of Rheumatology in Boston, provide encouraging news for the 20 million Americans suffering from osteoarthritis, a disease characterized by the breakdown of the shock-absorbing cartilage in the body's joints.
Osteoarthritis accounts for more than half of all arthritis cases in the United States, according to the Arthritis Foundation. Seventy-four percent involve women. The risk of developing osteoarthritis increases with age and obesity, particularly for weight-bearing joints such as the knees and hips.
Glucosamine products have been used for osteoarthritis in Europe for decades and have recently become popular in the United States. Sales of glucosamine supplements jumped 300 percent -- from $60 million to $240 million -- between 1995 and 1998, according to the Nutrition Business Journal in San Diego, which monitors the nutrition industry.
The body naturally produces glucosamine and uses it to form and repair cartilage. Glucosamine supplements, extracted from the shells of crabs, lobsters and shrimp, are believed to slow the deterioration of cartilage in osteoarthritis and act as an anti-inflammatory agent.
More research on the way
Experts say the Belgian study is the beginning of more rigorous evaluation for the widely touted and used supplement.
"This is the first time a study provides real scientific evidence of glucosamine's effectiveness," said John Klippel, M.D., medical director of the Arthritis Foundation in Atlanta.
John Renner, M.D., president of the National Council for Reliable Health Information and a frequent critic of dietary supplements, greeted the study with cautious optimism. "I would never give just one study the full go-ahead," Renner said. "But I'm impressed with the length of time."
Other rheumatology experts questioned whether units as small as a fraction of a millimeter could be analyzed accurately from an X-ray. The real test, they said, will come when the study is published in a scientific journal, where it will be subjected to the scrutiny of other professionals in the field, and other studies will try to duplicate its results.
One similar trial is already planned to begin next spring in the United States. Nine medical centers around the country will take part in the four-year study of glucosamine and chondroitin sulfate -- another substance thought to make cartilage more resilient -- in the treatment of osteoarthritis of the knee. The $6.6 million study is funded by the National Institutes of Health and will include more than 1,000 patients.
In the meantime, experts advise consumers to discuss the supplements with their doctors before using them. They also suggest sticking with reliable manufacturers when buying dietary products and herbal supplements.
Copyright 1999 webmed, Inc. All rights reserved.
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