title: Bone turnover markers in patients with differentiated thyroid carcinoma after levothyroxine withdrawal.
abstract: BACKGROUND
  Patients receiving postoperative radioiodine therapy for advanced differentiated thyroid carcinoma (DTC) are repeatedly in short-term thyroid hormone deficiency, whose bone turnover state is not fully understood.
  
  
  METHODS
  Serum bone turnover markers (BTMs), bone specific alkaline phosphatase (BALP), type 1 procollagen N-terminal propeptide (P1NP), osteocalcin (OC), and the beta-isomerized C-terminal telopeptide of type 1 collagen (beta-CTx) were measured in 50 adult male DTC patients after 4-week suspension of levothyroxine replacement therapy and 40 matched euthyroid controls. Relationships between parameters of thyroid function (free triiodothyronine, FT3; free thyroxine, FT4; thyroid stimulating hormone, TSH) and the BTMs were studied.
  
  
  RESULTS
  The patients had significantly decreased OC (-37.6%, P<0.001) and beta-CTx (-35.5%, P<0.001) compared with the controls, showing FT3 as the independent risk factor for OC (R2=0.425, P<0.001) and beta-CTx (R2=0.124, P<0.001). Partial correlation analysis showed that only FT3 was significantly correlated with OC after controlling FT4 and TSH (r=0.362, P=0.001).
  
  
  CONCLUSIONS
  DTC patients have moderately decreased bone turnover after short-term suspension of thyroxine suppressive therapy, with serum FT3 concentration as the predominant and independent risk factor.
authors.affiliation: The Immunoassay Laboratory, Department of Nuclear Medicine, Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai, China. gaookok@163.com
authors.forename: Yun-Chao
authors.initials: YC
authors.lastname: Gao
authors.forename: Qing
authors.initials: Q
authors.lastname: Gu
authors.forename: Qiao-Ping
authors.initials: QP
authors.lastname: Liu
authors.forename: Wen-Li
authors.initials: WL
authors.lastname: Ge
authors.forename: Han-Kui
authors.initials: HK
authors.lastname: Lu
mesh_terms: D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers / Q000097:blood*; D015992:Body Mass Index; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism*; D002112:Calcifediol / Q000097:blood; D006801:Humans; D007037:Hypothyroidism / Q000097:blood; D008297:Male; D015675:Osteocalcin / Q000097:blood*; D010281:Parathyroid Hormone / Q000097:blood; D012044:Regression Analysis; D013964:Thyroid Neoplasms / Q000097:blood* / Q000188:drug therapy* / Q000473:pathology; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use*; D014284:Triiodothyronine / Q000097:blood
chemical_list: D015415:Biomarkers; D010281:Parathyroid Hormone; D014284:Triiodothyronine; D015675:Osteocalcin; D013972:Thyrotropin; D000469:Alkaline Phosphatase; D002112:Calcifediol; D013974:Thyroxine