Biochemical markers of bone metabolism in patients with fracture of the distal forearm.

Biomarkers for bone turnover have established a place in the investigation and follow-up examinations of patients with osteoporosis, but has received little attention for the possibility that the fracture itself might interfere with the interpretation of the results. In this investigation of patients with fracture of the distal forearm, biomarkers for bone formation (serum osteocalcin and alkaline phosphatases) and for resorption (urinary calcium and hydroxyproline) were determined together with serum calcium and parathyroid hormone (PTH) in longitudinal and cross-sectional studies. During 16 weeks of follow-up examinations, starting on the day of the fracture, 13 patients with Colles' fracture displayed a consistent pattern with a moderate increase in serum alkaline phosphatase and osteocalcin, whereas the indices of bone resorption appeared unaffected. There was also a significant increase in the serum calcium concentration and a reciprocal decrease in serum PTH. A cross-sectional comparison between 99 patients and controls showed elevated osteocalcin levels in the patients and an inverse relationship between these levels and bone mineral density. The findings demonstrate that fracture healing should be considered in the interpretation of biomarkers in osteoporotic patients, and that among patients with a fracture of the distal forearm, those with biochemical evidence of increased bone turnover have the lowest bone mass.