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Questions & Answers
NIH Study on Glucosamine/Chondroitin Sulfate for Knee Osteoarthritis

What is the National Institutes of Health (NIH) study of the efficacy of glucosamine and chondroitin sulfate in knee osteoarthritis?
The study is the first multicenter clinical trial in the United States to test the effects of the dietary supplements glucosamine and chondroitin sulfate for treatment of osteoarthritis of the knee. The study will test whether glucosamine and chondroitin sulfate used separately or in combination are effective in reducing pain and improving functional ability in patients with osteoarthritis of the knee.

The University of Utah School of Medicine was awarded a contract to coordinate this study, which will be conducted at nine study centers. The National Center for Complementary and Alternative Medicine (NCCAM) and the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) are the two National Institutes of Health (NIH) components responsible for initiating this study.

What is the purpose of the study?
Results of previous studies in the medical literature have yielded conflicting results on the effectiveness of glucosamine and chondroitin sulfate as effective treatments for osteoarthritis. This study will test the short-term (16 weeks) effectiveness of glucosamine and chondroitin sulfate in reducing pain and improving function in a large number of patients with osteoarthritis of the knee.

What prompted the NIH to study glucosamine and chondroitin sulfate for osteoarthritis?
On January 27, 1998, the National Center for Complementary and Alternative Medicine held a meeting to discuss the need, rationale, and feasibility of conducting a Phase III study (a human study involving over 1,000 patients to test the efficacy, safety, and side effects of a substance(s)) on glucosamine and chondroitin sulfate for the treatment of knee osteoarthritis. Meeting participants included experts in osteoarthritis, alternative medicine, biostatistics and family practice, and staff of the NIH and the U.S. Food and Drug Administration. The group determined that there is a real and urgent public health need to test these agents in a rigorous way, and that current scientific data support short-term testing of glucosamine and chondroitin sulfate for pain control and functional improvement of osteoarthritis.

What is the basic design of the study?
In this study, patients will be randomly assigned to receive either (1) glucosamine alone, (2) chondroitin sulfate alone, (3) glucosamine and chondroitin sulfate in combination, or (4) a placebo (an inactive substance that looks like the study substance). To reduce the chance of biased results, double-blind research procedures will be used to ensure that neither the researchers nor the patients will know to which of the four treatment groups the patients belong.

Each patient will be treated for 16 weeks. During this time, patients will be evaluated at monthly intervals and closely monitored for improvement of their osteoarthritis as well as for any possible adverse reactions to the agents. Medical evaluations and x rays will be used to document each patient's diagnosis. The primary outcome will be measured as improvement in pain. Improvement in function will be included as a secondary outcome. All patients will have the option to use acetaminophen (e.g., Tylenol®) as required to control severe pain from osteoarthritis throughout the clinical trial.

Where will the study be conducted?
The University of Utah School of Medicine, Salt Lake City, UT, will serve as the coordinating study center and oversee the research and patient recruitment efforts of nine study centers, to include:

How many patients are needed and when will the study begin?
It is anticipated that a total of 1,124 patients will be recruited for the study. Patient recruitment is expected to begin in February 2000.

Who will be eligible to participate in the study?
Patients with knee pain and x-ray evidence of osteoarthritis are encouraged to consider participation in the study. Patient recruitment will not begin for 6 months; however, interested patients should refrain from taking glucosamine or chondroitin sulfate prior to entering the study.

How can I sign up for the study?
Information on recruitment will be announced in the next few weeks through the University of Utah School of Medicine. Questions regarding specific patient issues will be best addressed by individual clinics and additional information will be forthcoming from them in the next few weeks. Other inquiries should be directed to Diana Kucmeroski, Study Coordinator, University of Utah School of Medicine, Rheumatology Division, 50 North Medical Drive, Salt Lake City, Utah 84132; phone (801) 585-6468.

What is osteoarthritis?
An estimated 21 million adults in the United States live with osteoarthritis–one of the most common types of arthritis. Osteoarthritis, also called degenerative joint disease, is caused by the breakdown of cartilage, which is the connective tissue that cushions the ends of bones within the joint. It is characterized by pain, joint damage, and limited motion. The disease generally occurs late in life, and most commonly affects the hands and large weight-bearing joints. Although the disease can impact several joints, the knees are often affected. Age, female gender, and obesity are risk factors for this condition.

What are glucosamine and chondroitin sulfate?
Glucosamine and chondroitin sulfate are natural substances found in and around the cells of cartilage. Researchers believe these substances may help in the repair and maintenance of cartilage. In addition, researchers believe that glucosamine inhibits inflammation and stimulates cartilage cell growth, while chondroitin sulfate provides cartilage with strength and resilience. Currently, glucosamine and chondroitin sulfate are classified as dietary supplements.

What is a dietary supplement?
A dietary supplement is a product (other than tobacco) intended to supplement the diet, which bears or contains one or more of the following dietary ingredients: a vitamin, mineral, amino acid, herb or other botanical; is intended for ingestion in the form of a capsule, powder, softgel or gelcap; and is not represented as a conventional food or as a sole item of a meal or the diet (as defined by the U.S. Dietary Supplement Health and Education Act, Oct. 25, 1994).

Resources for Further Information:

For information on complementary and alternative medicine, including research activities, conferences and events, contact the National Center for Complementary and Alternative Medicine Clearinghouse by mail at P.O. Box 8218 Silver Spring, Maryland 20907-8218, by phone at (888) 644-6226, or at its Web site at http://nccam.nih.gov.

For information on rheumatic diseases such as osteoarthritis and diseases of the musculoskeletal and skin systems, contact the National Institute of Arthritis and Musculoskeletal and Skin Diseases Information Clearinghouse by mail at NIAMS/National Institutes of Health, 1 AMS Circle, Bethesda, Maryland 20892-3675, by phone at (301) 495-4484 or at its Web site at http://www.nih.gov/niams.

For information on dietary supplement labeling requirements and safety monitoring, order the FDA Guide to Dietary Supplements from the U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition at (800) FDA-4010 or visit its Web site at http://www.cfsan.fda.gov/~dms/supplmnt.html.

For scientific citations and abstracts on dietary supplements, visit the NIH Office of Dietary Supplements Web site at http://odp.od.nih.gov/ods/databases/ibids.html for access to the International Bibliographic Information on Dietary Supplements (IBIDS) database. This database is maintained through an interagency partnership between the NIH Office of Dietary Supplements and the U.S. Department of Agriculture, National Agricultural Library, Food and Nutrition Information Center.

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