title: The effect of thyroid stimulating hormone suppressive therapy on bone geometry in the hip area of patients with differentiated thyroid carcinoma.
abstract: Subclinical hyperthyroidism has been reported to increase the fracture risk. However, the effect of thyroid stimulating hormone (TSH) suppressive therapy on bone geometry in the hip area of patients with differentiated thyroid carcinoma (DTC) is still unclear. The aim of this study was to investigate the effect of TSH suppression on bone geometry in the hip area of pre- and postmenopausal women with DTC. We conducted a retrospective cohort study including 99 women with DTC (25 pre- and 74 postmenopausal) who had received TSH suppressive therapy for at least 3years and 297 control subjects (75 and 222, respectively) matched for sex and age. Bone mineral density (BMD) in the spine and hip area and bone geometry at the femoral neck measured by dual energy X-ray absorptiometry (DXA) were compared between patients and controls. The association between thyroid hormone and bone parameters was investigated. All analyses of bone parameters were adjusted for age, body mass index, and serum calcium levels. In premenopausal subjects, TSH suppressive therapy was not associated with poor bone parameters. In postmenopausal subjects, patients with DTC undergoing TSH suppression showed lower cross-sectional moment of inertia (CSMI), cross-sectional area, and section modulus and thinner cortical thickness at the femoral neck than those of control subjects, whereas their femoral neck BMD was comparable with controls. Total hip BMD was lower in postmenopausal patients than in controls. CSMI and section modulus at the femoral neck were independently associated with serum free T4 levels in postmenopausal patients. The difference in femoral neck bone geometry between patients and controls was only apparent in postmenopausal DTC patients with free T4 >1.79ng/dL (23.04pmol/l), and not in those with free T4 levels ≤1.79ng/dL (23.04pmol/l). TSH suppression in postmenopausal DTC patients was associated with decreased bone strength by altering bone geometry rather than BMD in the hip area, especially the femoral neck. This alteration in bone quality was observed only in patients with free T4 levels above the upper normal limit.
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Republic of Korea.
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Moon
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Republic of Korea.
authors.forename: Kyong Yeun
authors.initials: KY
authors.lastname: Jung
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Republic of Korea.
authors.forename: Kyoung Min
authors.initials: KM
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Republic of Korea.
authors.forename: Sung Hee
authors.initials: SH
authors.lastname: Choi
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Republic of Korea.
authors.forename: Soo
authors.initials: S
authors.lastname: Lim
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Republic of Korea.
authors.forename: Young Joo
authors.initials: YJ
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Republic of Korea.
authors.forename: Do Joon
authors.initials: DJ
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Republic of Korea. Electronic address: janghak@snu.ac.kr.
authors.forename: Hak Chul
authors.initials: HC
authors.lastname: Jang
mesh_terms: D016022:Case-Control Studies; D005260:Female; D006615:Hip / Q000473:pathology*; D006801:Humans; D016014:Linear Models; D008875:Middle Aged; D015999:Multivariate Analysis; D013964:Thyroid Neoplasms / Q000097:blood / Q000188:drug therapy*; D013972:Thyrotropin / Q000627:therapeutic use*; D013974:Thyroxine / Q000097:blood
chemical_list: D013972:Thyrotropin; D013974:Thyroxine
keywords: Bone geometry; Bone mineral density; Differentiated thyroid carcinoma; TSH suppression