CALCIUM SUPPLEMENTS INCREASE THE SERUM LEVELS OF CROSS-LINKED N-TELOPEPTIDES OF BONE-COLLAGEN AND PARATHYROID-HORMONE IN RACHITIC NIGERIAN CHILDREN

Objectives: Biochemical markers of bone turnover were measured in the sera of 16 controls and 10 children with calcium-deficiency rickets, d uring a 12-week course of calcium supplementation (1 g CaCO3/d) that w as effective in healing the bone lesions of the rachitic children. Des ign and methods: Serum levels of crosslinked N-telopeptides of bone co llagen (NTx), parathyroid hormone (PTH), alkaline phosphatase (ALP), a nd urinary deoxypyridinoline (LP) were assayed at baseline and during the course of calcium therapy and compared with data of the 16 non-rac hitic controls. Results: Calcium therapy suppressed serum NTx and PTH levels in the rachitic children within 24 h; however, after the first week, PTH and NTx levels increased to the extent that at 12 weeks both were elevated when compared with controls or to baseline levels. Seru m levels of NTx and PTH were correlated in the controls and experiment al subjects (r = 0.63, p < 0.001). Conclusions: The rate of bone resor ption, as estimated by serum NTx concentration, is increased during th e healing of rachitic lesions. Copyright (C) 1998 The Canadian society of Clinical Chemists.