Ross D S, Neer R M, Ridgway E C, Daniels G H
Am J Med. 1987 Jun;82(6):1167-70. doi: 10.1016/0002-9343(87)90219-1.
Spontaneous hyperthyroidism and that due to excessive administration of thyroid hormone result in osteopenia. Bone density was measured in 28 white premenopausal female patients who were taking commonly prescribed suppressive doses of L-thyroxine (mean dose 0.171 +/- 0.035 g) for five or more years. The thyroxine level was 13.5 +/- 2.6 micrograms/dl (normal 8.0 +/- 2.4 micrograms/dl), the free thyroxine index was 4.4 +/- 1.0 (normal 2.4 +/- 0.8), and the triiodothyronine value was 154 +/- 26 ng/dl (normal 132 +/- 32 ng/dl). Basal thyrotropin was undetectable (less than 0.08 microIU/ml) in 23 patients, and thyrotropin measured 20 minutes after thyrotropin-releasing hormone administration was not demonstrable in 13 patients and subnormal in 10 patients. Women who had taken L-thyroxine for 10 or more years (n = 12, age 37 +/- 4 years) had a 9 percent reduction in bone density (0.667 +/- 0.044 g/cm2, p less than 0.01) compared with normal premenopausal age-matched control subjects (n = 56, age 35 +/- 6 years, bone density 0.733 +/- 0.055 g/cm2). It is concluded that prolonged suppressive L-thyroxine treatment may result in mild subclinical hyperthyroidism with adverse effects on bone. Patients requiring suppression of the pituitary-thyroid axis should be given the smallest dose of L-thyroxine necessary to achieve a satisfactory clinical response.
自发性甲状腺功能亢进以及因过量服用甲状腺激素导致的甲状腺功能亢进都会引起骨质减少。对28名绝经前白人女性患者进行了骨密度测量，这些患者服用常用剂量的L-甲状腺素（平均剂量0.171±0.035克）进行抑制治疗已达五年或更久。甲状腺素水平为13.5±2.6微克/分升（正常为8.0±2.4微克/分升），游离甲状腺素指数为4.4±1.0（正常为2.4±0.8），三碘甲状腺原氨酸值为154±26纳克/分升（正常为132±32纳克/分升）。23名患者的基础促甲状腺激素检测不到（低于0.08微国际单位/毫升），13名患者在注射促甲状腺激素释放激素20分钟后促甲状腺激素检测不到，10名患者促甲状腺激素低于正常水平。服用L-甲状腺素10年或更久的女性（n = 12，年龄37±4岁）与年龄匹配的绝经前正常对照受试者（n = 56，年龄35±6岁，骨密度0.733±0.055克/平方厘米）相比，骨密度降低了9%（0.667±0.044克/平方厘米，p<0.01）。结论是，长期使用抑制剂量的L-甲状腺素治疗可能导致轻度亚临床甲状腺功能亢进，并对骨骼产生不良影响。需要抑制垂体-甲状腺轴的患者应给予能达到满意临床反应的最小剂量的L-甲状腺素。
