Effect of hypoparathyroid on bone mineral density of lumber spine in postmenopausal women with differentiated thyroid cancinoma.

OBJECTIVE: To investigate the effect of hypoparathyroid on bone mineral density in postmenopausal women with differentiated thyroid carcinoma (DTC).

SUBJECT AND METHODS: Postmenopausal women with postoperative DTC, and undergoing thyroid residual ablation or for metastases treatment were collected and followed for two years. They were divided into hypoparathyroid group (PTH<15pg/mL) and a normal cognitive group (PTH>15pg/mL). Bone mineral density (BMD) at the lumbar spine was analyzed using dual-energy X-ray absorptiometry (DXA) at baseline, 6, 12 and 24 months. All patients had calcium and active vitamin D supplementation.

RESULTS: The thyroid cancers included 211 papillary carcinomas, 14 follicular carcinomas. The majority of them were retired from previous work (157/225, 70%). There were 45 DTC patients in hypoparathyroid group and 180 patients in PTH normal group (postmenopausal controls). They are comparable in age, TSH suppression, BMD at baseline. There is no significant difference in BMD of lumbar spine between hypoparathyroid group and postmenopausal controls at baseline 6, 12 and 24 months follow-up which were1.03±0.14 and 1.04±0.18 (t=0.4, P=0.69), 1.04±0.13 and 1.01±0.19 (t=1.25, P=0.21), 1.06±0.15 and 1.02±0.16 (t=1.16, P=0.26), 1.06±0.21 and 1.01±0.17 (t=0.93, P=0.29), respectively. Areal BMD was increased by 2.9% in hypoparathyroid group in the lumbar spine at 12 and 24 months follow-up, while decrease of 2.9% in postmenopausal controls. No increase in BMD at lumbar spine was found in postmenopausal controls.

CONCLUSION: Transient hypoparathyroid increased BMD at lumbar spine by DXA in postmenopausal DTC patients compared to postmenopausal controls.