Dietary Supplement May Slow Progression of Knee Osteoarthritis
Nov. 15, 1999 (Boston) -- In news that is sure to have dietary supplement makers falling to their knees in thanks, European researchers report on results of a 3-year study indicating that a single daily dose of glucosamine sulfate appears to decrease the progression and ameliorate the signs and symptoms of osteoarthritis of the knee. The findings were presented here Monday at the 63rd Annual Scientific Meeting of the American College of Rheumatology (ACR).
Osteoarthritis is caused by just general wear and tear of the joints. In people who have the condition, the cartilage, the cushion at the end of the bones, deteriorates, which in turn reduces the space between the bones (at the joint), called joint space narrowing, and leads to pain. More than 20 million Americans suffer from the disease; most of them are over 45.
In the study of 212 patients, some took 1,500 mg of glucosamine sulfate orally each day and some took a placebo. X-rays showed that of the patients who took glucosamine sulfate, 22% had X-ray evidence of joint deterioration, compared with 38% of those who took the placebo. At the end of the 3-year study, patients on glucosamine had nearly 50% less joint-space narrowing and experienced significant improvement of symptoms, says Jean-Yves Reginster, MD, PhD, from the University of Liege, Belgium.
"For the first time, we have shown that a compound may be able at least to slow down the progression of osteoarthritis," Reginster says.
But if glucosamine sulfate works as claimed, it still isn't clear why. Other studies have shown it may work by shutting down the inflammatory proteins that chew up cartilage.
A U.S. rheumatologist tells WebMD that he finds glucosamine to be only moderately effective for treatment of osteoarthritis of the knee. "My personal practice is that if my patients come in and tell me that they're interested in taking it or that they're currently taking it, I recommend that they take it for a minimum of 12 weeks to see if they're going to have a therapeutic effect in terms of symptom modification," says Marc Hochberg, MD, MPH. Hochberg is chairman and professor of rheumatology at the University of Maryland.
But before patients rush out to the drugstore or health food market to snap up glucosamine pills, they should be aware that the substance is controlled and regulated as a prescription-only drug in Europe, and is therefore a standardized product. In contrast, glucosamine sulfate is an over-the-counter dietary supplement in the U.S., free from FDA oversight. It's therefore subject to wide variations in quality, potency, and, presumably, efficacy.
"My major concern is that nutritional supplements in the United States are not regulated to the degree that [prescription strength] drugs are regulated, and that when you go into the store, you're not sure what you're getting," Hochberg says.
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