Paul T L, Kerrigan J, Kelly A M, Braverman L E, Baran D T
Department of Medicine, University of Massachusetts Medical School, Worcester 01605.
JAMA. 1988 Jun 3;259(21):3137-41.
The effect of long-term L-thyroxine (L-T4) therapy on axial skeleton bone density was studied in 31 premenopausal women; the bone densities of these women were compared with the bone densities of 31 age- and weight-matched women without thyroid or bone abnormalities. The women receiving L-T4 therapy had been receiving the medication for a minimum of five years. There was no difference in calcium intake or excretion between the L-T4-treated women and the controls. Women receiving L-T4 had increased serum thyroxine concentrations (134 +/- 5 vs 95 +/- 3 nmol/L [10.4 +/- 0.4 vs 7.4 +/- 0.2 micrograms/dL]), an increased free thyroxine index (9.4 +/- 0.4 vs 6.8 +/- 0.2), and decreased serum thyroid-stimulating hormone concentrations (0.9 +/- 0.2 mU/L vs 2.1 +/- 0.3 mU/L [0.9 +/- 0.2 vs 2.1 +/- 0.3 microU/mL]). Serum triiodothyronine concentrations were normal and were similar in both groups. Women treated with L-T4 had a 12.8% lower bone density at the femoral neck and a 10.1% lower bone density at the femoral trochanter compared with matched controls. In contrast, lumbar spine bone density was similar in the two groups. The data suggest that long-term L-T4 therapy, which is often given at supraphysiologic dosages, may predispose patients to decreased bone density in the hip and may increase the risk of age-related bone loss. It is advisable, therefore, to employ a dosage of L-T4 that is carefully monitored to avoid the long-term use of dosages that are excessive for the thyroid condition being treated.
对31名绝经前女性进行了长期左旋甲状腺素（L-T4）治疗对中轴骨骼骨密度影响的研究；将这些女性的骨密度与31名年龄和体重匹配、无甲状腺或骨骼异常的女性的骨密度进行比较。接受L-T4治疗的女性接受该药物治疗至少五年。接受L-T4治疗的女性与对照组在钙摄入或排泄方面没有差异。接受L-T4治疗的女性血清甲状腺素浓度升高（134±5 vs 95±3 nmol/L [10.4±0.4 vs 7.4±0.2 μg/dL]），游离甲状腺素指数升高（9.4±0.4 vs 6.8±0.2），血清促甲状腺激素浓度降低（0.9±0.2 mU/L vs 2.1±0.3 mU/L [0.9±0.2 vs 2.1±0.3 μU/mL]）。两组血清三碘甲状腺原氨酸浓度均正常且相似。与匹配的对照组相比，接受L-T4治疗的女性股骨颈骨密度低12.8%，股骨转子骨密度低10.1%。相比之下，两组腰椎骨密度相似。数据表明，长期L-T4治疗（通常以超生理剂量给药）可能使患者易患髋部骨密度降低，并可能增加与年龄相关的骨质流失风险。因此，建议使用经过仔细监测的L-T4剂量，以避免长期使用对所治疗的甲状腺疾病来说过高的剂量。
