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

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

目的了解甲状腺素短期替代治疗对甲状腺功能低减（甲减）患者骨矿代谢的影响。方法对２９例原发甲减患者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（ＢＭＤ），以３７例健康者为对照。并对甲减患者甲状腺功能参数与骨矿代谢参数作相关性分析。结果甲减组治疗前血ＢＧＰ［（３４５±２２１）μｇ／Ｌ］低于对照组［（４９３±２９２）μｇ／Ｌ］，Ｐ＜００５；尿ＤＰＤ与对照组相似；绝经前甲减患者ＢＭＤ与对照组比较差异无显著性，绝经后患者显著降低（Ｐ＜００１～０００１）。替代治疗后ＢＧＰ和ＤＰＤ显著升高（Ｐ＜００５）；ＢＭＤ较治疗前有所下降，但无统计学意义（Ｐ＞００５），绝经前患者ＢＭＤ下降约０７％，绝经后患者下降１７％～５１％，绝经前后比较差异无显著性（Ｐ＞００５）。游离三碘甲腺原氨酸（ＦＴ３）与ＢＧＰ，ＦＴ３、游离甲状腺素（ＦＴ４）与ＤＰＤ呈正相关，股骨颈、大?

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 radioimmunoassary (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.