Markers of bone turnover: consideration on their clinical application in osteoporosis.

Osteoporosis is a condition in which an imbalance appears between bone resorption and formation, with bone resorption exceeding formation. However since the rate of bone loss varies significantly from one individual to another resulting in different degrees of osteoporosis, new biochemical techniques to measure products of bone resorption and bone formation have been used in the last years allowing us to evaluate the degree of bone turnover. Bone tissue is constituted of an inorganic component and an organic matrix of collagen and noncollagenous proteins. Suitable bone marker should report the formation and degradation of all these constituents. Today markers of bone formation and markers of bone resorption are available. According to recent literature and personal data assessment of bone metabolism by the specific biochemical markers is helpful to select osteoporotic patients with high or low bone turnover and these parameters should be used to evaluate whether bone remains sensitive to different therapies.