CHANGES IN BONE MASS AND SERUM MARKERS OF BONE METABOLISM AFTER PARATHYROIDECTOMY

Background. Primary hyperparathyroidism (PHPT) is associated with an i ncreased bone turnover. The simultaneous use of biochemical and bone m ass measurements before and after parathyroidectomy is sparsely report ed. This study was carried out to evaluate changes in, bone mass and m arkers of bone metabolism in postmenopausal women with PHPT after para thyroidectomy. Methods. Twelve women, mean age of 63 gears, were inves tigated. Measurements of bone mineral density (total body, spine, hip, and forearm bone mineral density) with dual-energy x-ray absorptiomet ry were performed before operation and at follow-up at a median of 23 months. Concomitantly, changes in serum intact parathyroid hormone, bo ne-specific alkaline phosphatase (B-ALP), osteocalcin, carboxyterminal propeptide of type I procollagen, and the immunoactive carboxytermina l telopeptide of type I collagen were recorded. Results. At follow-up a significant increase in bone mineral density of the spine (p < 0.05) , femoral neck (p < 0.05), Ward's triangle (p < 0.05), and trochanter (p < 0.01) was observed, No significant changes in the forearm were re gistered. Levels of parathyroid hormone, B-ALP, and osteocalcin were e levated and Intercorrelated before operation. The serum levels of thes e parameters decreased significantly after operation. Serum levels of carboxyterminal propeptide of type I procollagen and the immunoactive carboxyterminal telopeptide of type I collagen did not significantly d iffer from a reference population, and so major changes were observed at follow-up. Conclusions. Bone mineral density in the spine and hip i s improved after parathyroidectomy in post-menopausal women with prima ry hyperparathyroidism. Serum levels of B-ALP and osteocalcin are elev ated in PHPT and decrease after operation. The clinical usefulness of serum markers of collagen metabolism in investigating bone metabolism in PHPT seems limited.