Effect of Glucosamine on Joint Structure and Quality of Life (JOG)

Reduced knee function is a significant cause of physical limitations and disability. As cartilage deteriorates due to aging, wear-and-tear, injury, or disease, joint space narrowing and pain can develop. The lost of articular cartilage arises from an imbalance between cartilage synthesis and cartilage degradation. When cartilage needs to be remodeled, enzymes such as matrix metalloproteinases (MMPs) degrade type II collagen. It now may be possible to use new molecular markers of cartilage degradation to assess the progression of joint loss in comparison with radiographic changes of the knee joint. Urinary excretion of C-terminal cross linking telopeptide of type II collagen (CTX-II) is a new molecular marker of cartilage tissue degradation metabolism. Recent evidence suggests that glucosamine, a dietary supplement, may provide some relief from joint pain and may increase the functional ability to participate in activities of daily living. This may be a result of these dietary supplements stimulating tissue repair such as cartilage in the affected joints, or by inhibiting the degradation of cartilage through an inhibition of enzymes. Moreover, Braham, Dawson, \& Goodman (2003) reported increases in function in adults with knee pain following 12 -weeks of glucosamine supplementation. It is unclear, however, if glucosamine delivered via a liquid carrier would improve physical function and impact quality of life measures in people who have experienced loss of knee cartilage. Glucosamine is a precursor for glycosaminoglycans, which are a major component of both joint cartilage and skin. Potential benefits of glucosamine on skin have been reported previously. It is possible that glucosamine in a beverage might also improve skin parameters over time. Comparisons: 100 men and women with mild to moderate joint pain taking a liquid with glucosamine, compared to 100 men and women with mild to moderate joint pain taking a liquid with placebo.