COLLAGEN CROSSLINKED N-TELOPEPTIDE

Osteoporosis is the most common bone disease in the West. It is often called the “silent disease” because bone loss occurs without symptoms. The formation and maintenance of bone mass is dependent on a combination of factors that include genetics, nutrition, exercise, and hormone function. Normally the rate of bone formation is equal to the rate of bone resorption. After midlife, the rate of bone loss begins to increase. Osteoporosis is more commonly identified in women than in men. Other risk factors include thin, small-framed body structure; family history of osteoporosis; diet low in calcium; white or Asian race; excessive use of alcohol; cigarette smoking; sedentary lifestyle; long-term use of corticosteroids, thyroid replacement medications, or antiepileptics; history of bulimia, anorexia nervosa, chronic liver disease, or malabsorption disorders; and postmenopausal state. Osteoporosis is a major consequence of menopause in women owing to the decline of estrogen production. Osteoporosis is rare in premenopausal women. Estrogen replacement therapy (after menopause) is one strategy that has been commonly employed to prevent osteoporosis, although its exact protective mechanism is unknown. Results of some recently published studies indicate that there may be significant adverse side effects to estrogen replacement therapy; more research is needed to understand the long-term effects (positive and negative) of this therapy. Other treatments include raloxifene (selectively modulates estrogen receptors), calcitonin (interacts directly with osteoclasts), and bisphosphates (inhibit osteoclast-mediated bone resorption).A noninvasive test to detect the presence of collagen cross-linked N-telopeptide (NTSBxsb) is used to follow the progress of patients who have begun treatment for osteoporosis. NTSBxsb is formed when collagenase acts on bone. Small NTSBxsb fragments are excreted in the urine after bone resorption. A desirable response, 2 to 3 months after therapy is initiated, is a 30% reduction in NTSBxsb and a reduction of 50% below baseline by 12 months. [ABSTRACT FROM AUTHOR]