Chapter 65 - Biochemical markers of bone turnover in osteoporosis

Abstract

Bone turnover markers (BTMs) are divided into the markers of bone formation and those of bone resorption. N-terminal collagen type I extension propeptide and serum C-terminal cross-linking telopeptide of type I collagen have been selected as the reference markers of bone formation and resorption, respectively. BTM levels are influenced by numerous factors. BTM cannot be used for the diagnosis of osteoporosis or to predict accelerated bone loss. The utility of BTMs for fracture prediction in postmenopausal women requires further studies. Bone resorption inhibitors decrease BTM levels. Changes in BTMs after their withdrawal vary according to their mechanisms of action. Bone formation–stimulating drugs increase the concentrations of bone formation markers. BTM may be used for dose-finding studies, bridging studies, and, hopefully, for monitoring the antiosteoporotic treatment. Sequential therapy trials, head-to-head comparisons, and combination therapy studies improve our understanding of the mechanisms of action of antiosteoporotic drugs on bone metabolism.