Bone loss and bone metabolic markers in hyperparathyroidism

Abstract

In this paper we described the relation between serum bone metabolic markers and bone mineral densities (BMD) in both cortical bone and trabecular bone in 22 patients with primary hyperparathyroidism (PHP) and in 108 patients with renal hyperparathyroidism (RHP). As bone formation markers, total alkaline phosphatase (AlP), intact osteocalcin and the carboxyterminal propetide of type I procollagen (PICP) were measured. As bone resorption markers, the carboxyterminal pyridinoline cross-linked telopeptide of type I collagen (ICTP) and tartrate-resistant acid phosphatase (TRACP) were measured. BMDs in the mid-radius and lumbar vertebrae (L2–4) were assessed using dual energy X-ray absorptiometry. Among the bone formation markers, the serum levels of AlP and and osteocalcin seemed to reflect osteoblast activity more accurately than PICP. Regarding the bone resorption markers, the serum levels of ICTP seemed to reflect osteoclast function more adequately than TRACP. In both PHP and RHP patients, the decrease in R-BMD was more prominent than that in L-BMD. In RHP patients, the decrease in BMDs, especially those of the midradius, negatively correlated with both bone formation markers and bone resorption markers. We concluded that the excessive PTH secretion elevates both the markers of bone formation and resorption, and that BMD decreases more significantly in cortical bone than in trabecular bone. Measurements of bone metabolic markers may prove to be useful for predicting bone loss in hyperparathyroidism.