[The importance of bone remodelling parameters in the management of osteoporosis]

Bone is continuously remodelled. Bone turnover markers reflect the activity of osteoblasts and osteoclasts during remodelling. Collagen synthesis by osteoblasts is reflected by the formation of bone-specific alkaline phosphatase (BALP), osteocalcin (OC) and procollagen N-propeptides (P1NP). During bone resorption, fragments of collagen (N- and C-terminal telopeptides, pyridinolines) and tartrate-resistant acid phosphatase (TRACP) are released. These markers enable a dynamic assessment of bone remodelling. P1NP is recommended as a reference marker for bone formation and ßCTX for bone resorption. Using and, above all, interpreting the results of bone turnover markers, it is impor-tant to take into account the various sources of variability of these markers, such as diurnal rhythm, day-to-day fluctuations, food intake and also the stability of the marker after blood sampling. The most important area for the clinical use of bone turnover markers is the monitoring of antiresorptive or anabolic treatments of osteoporosis. A short-term decrease in bone turnover during antiresorptive therapy correlates with an increase in bone density after 1-2 years and a decrease in fracture risk. The bone formation markers, especially P1NP, correlate with the increase in bone mineral density on anabolic treatment.