According to a 2010 review in "American Family Physician," osteoarthritis of the knee and hip affect 10 percent and 5 percent, respectively, of American adults over the age of 60. Although most physicians initially prescribe nonsteroidal anti-inflammatory drugs, or NSAIDs, for these conditions, many people turn to alternative approaches, such as glucosamine or chondroitin. Neither of these preparations has been approved for treating arthritis in the United States.
Glucosamine
Glucosamine, a sugar-like molecule that is found in nearly all of your tissues, is normally manufactured in the human body and used as a building block for cartilage, tendons, ligaments and other connective tissues. It is available as a supplement in several forms, including glucosamine sulfate, glucosamine hydrochloride and N-acetyl-glucosamine. Glucosamine forms one-half of keratan sulfate, an important molecule that is found in healthy cartilage. People with osteoarthritis have less keratan sulfate in their joints.
Chondroitin
Chondroitin is a polysaccharide, or long-chain sugar molecule, that exhibits gel-forming properties in aqueous environments. Like glucosamine, chondroitin sulfate is an important component of cartilage, where it serves as a shock absorber. In joints that are affected by arthritis, the cartilage typically erodes and thins, and many of its important constituents, such as chondroitin, are lost.
Early Research
For many years it was believed that supplementation with glucosamine and chondroitin provided some relief from the symptoms of arthritis, such as pain and reduced range of motion. However, until recently, clinical trials produced inconsistent results, possibly due to the different preparations and dosages incorporated into the study designs. In 2005, a comprehensive review of the scientific literature attested to some of the uncertainty surrounding these early trials.
Recent Research
An exhaustive 2010 review involving nearly 4,000 patients and published in the "British Medical Journal" contends that glucosamine, chondroitin or a combination of the two are not any more effective than placebo for reducing joint pain or slowing the progression of joint space loss in patients with osteoarthritis. Notably, the review's authors reported that industry-sponsored trials demonstrated more benefit from these supplements than independently funded studies, and the authors discouraged insurers from paying for glucosamine or chondroitin when they were recommended by physicians who treat osteoarthritis.
Considerations
Osteoarthritis, like rheumatoid arthritis and other joint disorders, is a heterogeneous condition. Some patients with extensive joint involvement have minimal pain, while others with relatively little joint damage exhibit a great deal of discomfort. This variability among patients has been cited as a confounding factor in clinical research, including recent, well-designed studies. Based on experience and the inconsistencies of clinical trials, many experts still recommend the use of glucosamine, usually glucosamine sulfate, and chondroitin for reducing arthritis symptoms. If you would like to try glucosamine or chondroitin, check with your physician.
References
- "American Family Physician: Clinical Evidence Handbook"; Osteoarthritis of the Hip; D. Scott; 2010
- "The Cochrane Database of Systematic Reviews"; Glucosamine Therapy for Treating Osteoarthritis; T. Towheed, et al.; 2005
- PubMed: Effects of Glucosamine, Chondroitin or Placebo in Patients With Osteoarthritis of Hip or Knee: Network Meta-Analysis
