HYPOPARATHYROIDISM COUNTERACTS RISK-FACTORS FOR OSTEOPOROSIS

Although increased bone density has been reported in patients with hyp oparathyroidism, it is not known whether hypoparathyroidism can overco me the influence of risk factors for osteoporosis and whether the incr eased bone density is uniform throughout the entire skeleton or greate r in certain regions depending on the bone composition and location. I n the current study, bone density was measured in patients with postsu rgical hypoparathyroidism and risk factors for osteoporosis, Bone mine ral density was determined in eight patients with postsurgical hypopar athyroidism, one with idiopathic hypoparathyroidism, and two with pseu dohypoparathyroidism in eight different areas of the skeleton using we ll established methods: single photon absorptiometry of the radius, du al energy x-ray absorptiometry of the spine, hip, and the whole skelet on, and quantitative computed tomography of the spine, Risk factors fo r osteoporosis were documented in each subject, The data showed that d espite the presence of 1-4 risk factors for osteoporosis, patients wit h postsurgical hypoparathyroidism had bone mineral density above the n ormal mean in most locations. The locations with the highest increment were the Ward's triangle and the trochanter area of the proximal femu r (dual energy x-ray absorptiometry) (Ward's: Z score + 1.59 +/- 0.57, P < 0.03; trochanter 1.31 +/- 0.42, P < 0.02). The elevation of bone density was not observed in one patient with idiopathic hypoparathyroi dism, and variable results were observed in two patients with pseudohy poparathyroidism. Based on these findings, in postsurgical hypoparathy roidism, the bone mineral density is above the normal mean despite the presence of risk factors for osteoporosis, and both cortical and trab ecular bone are affected.