左旋甲状腺素替代治疗对甲状腺功能低减患者骨矿代谢的影响

目的 了解甲状腺素短期替代治疗对甲状腺功能低减（甲减）患骨矿代谢的影响。方法 对２９例原发甲减患治疗前及左旋甲状腺素替代治疗（１１．５±２．５）个月，临床症状缓解，血清学指标恢复正常后，采用ＥＬＩＳＡ法测定尿脱氧吡啶啉（ＤＰＤ），ＲＩＡ法测定血清降钙素（ＣＴ）、甲状旁腺素（ＰＴＨ－Ｍ）、骨钙素（ＢＧＰ）等，应用双能Ｘ线吸收法测定第２￣４腰椎（Ｌ２－４）和股骨颈、大转子、Ｗａｒｄ三角骨密度（ＢＭ

The effects of levothyroxine replacement therapy on bone and mineral metabolism in patients with hypothyroidism

OBJECTIVE: To investigate the effects of short-term thyroid hormone replacement therapy on bone and mineral metabolism in patients with hypothyroidism. METHODS: Enzyme linked immunosorbent assay (ELISA) was used to measure urinary deoxypyridinoline (DPD) and radioimmunoassay (RIA) to measure serum calcitonin (CT), parathyroid hormone (PTH-M), bone GLA protein (BGP), free T(3) (FT(3)), free T(4) (FT(4)) and thyroid-stimulating hormone (TSH) in 29 patients with hypothyroidism before and after treatment with levothyroxine for (11.5 +/- 2.5) months. Dual energy X-ray absorptiometry was used to measure bone mineral density (BMD) of their spine (L(2 - 4)) and femur neck, trochanter and Ward's triangle. The results were compared with those in 37 healthy controls. RESULTS: In hypothyroidism patients before treatment, serum BGP level was significantly lower (P < 0.05) than but urinary DPD was similar with those of control. BMD was significantly lower in postmenopausal patients (P < 0.01 - 0.001) than that in control group, but there was no change in premenopausal patients. After replacement therapy serum BGP and urinary DPD elevated significantly (P < 0.05), whereas BMD decreased slightly both in the premenopausal and postmenopausal patients when compared with that before treatment, with no statistical significance (P > 0.05). BMD decreased by 0.7% and 1.7% - 5.1% in premenopausal and postmenopausal patients respectively, but there was no significant difference between these two groups (P > 0.05). FT(3) was positively correlated with BGP. FT(4) and FT(3) were positively correlated with DPD. BMD of femur neck and trochanter sites was negatively correlated with FT(4). CONCLUSION: Short-term physiological dose levothyroxine replacement therapy causes increase of bone turnover and leads to bone mass loss to various extent on hypothyroidism patients.