The Bone Mineral Density and Bone Metabolism of Patients with Differentiated Thyroid Carcinoma and who are Receiving Long-term TSH Suppressive Therapy

Seung Hyun Park, Jandee Lee, Soo Youn Choi, Euy-Young Soh
2008 The Korean Journal of Endocrine Surgery  
Purpose: The clinical implications of long-term suppressive thyroxine (TSH) therapy on the skeletal system are critical, largely because of the favorable prognosis of differentiated thyroid carcinomas (DTC). However, the potentialdeleterious effects of TSH suppressive therapy on the bone metabolism remain controversial. The aim of this prospective study was to assess the effects of chronic L-thyroxine (LT4) treatment with supraphysiologic doses of TSH on the bone mineral density (BMD) and
more » ... ity (BMD) and biochemical bone remodeling markers. Methods: This cross-sectional study was designed to compare patients with DTC and who were treated with LT4 for more than 2 years after thyroidectomy with an age-matched and gender-matched healthy control group. A total of 100 female outpatients (mean age: 47.5±13.8; 38 pre and 62 post-menopausal) who were on LT4 for between 2 and 10 yearswere enrolled. One hundred and three age-matched healthy volunteers were recruited as a control group. Laboratory tests were performed to exclude other possible factors for secondary osteoporosis. We measured the BMD by dual energy X-ray absorptiometry (DEXA), and bone turnover was assessed by several biochemical parameters. Results: Our data showed no significant difference between the bone markers for the study group and the control group that had a premenopausal status. However, for the patients with a postmenopausal status, the serum levels of bone alkaline phosphatase were significant higher in the study group than that in the control group (P=0.038). We also found no significant difference between the study patients and the age-and weight-matched controls for the BMD at any site of measurement. Conclusion: This preliminary report suggests that bone turnover and accelerated bone loss might be related to the long-standing TSH suppression in postmenopausal women. Future prospective studies with an increased number of studied patients and a prolonged time of observation will be necessary in order to better assess the relative risk of osteoporosis in patients who are undergoing TSH suppressive treatment. (Korean J Endocrine Surg 2008;8:89-94) 서 론 갑상선호르몬은 골 교체율(bone turnover rate)의 조절에 관여하므로 정상적인 골 성장 및 발육에 주요한 역할을 한 다. 따라서, 갑상선기능항진증이 지속되면 골 교체율의 증 가로 골흡수(bone resorption) 및 골형성(bone formation)의 불 균형이 야기되어 골다공증(osteoporosis) 및 병적 골절(pathologic fracture)의 발생률이 높아진다고 알려져 있다.(1-5) 골 대사에 직접적인 영향을 미치는 갑상선 호르몬은 활성 형(active)인 T3이며, 각각의 전달과정에서 다양한 성장 인자 및 시토카인(cytokine) 등이 간접적으로 관여한다고 알려져 있었다. 하지만, 최근 갑상선자극호르몬(Thyroid stimulating hormone, TSH)이 혈중 갑상선 호르몬과 관계없이 독립적인 세포내 신호전달체계를 통해 골격 재형성(skeletal remodeling) 에 결정적인 역할을 한다고 보고되어, TSH 억제와 골밀도 변
doi:10.16956/kjes.2008.8.2.89 fatcat:kzm6v5h3rrfulpmbkecbehve3y