title: Low levels of serum vitamin D3 are associated with autoimmune thyroid disease in pre-menopausal women.
abstract: BACKGROUND
  Low serum vitamin D levels have been associated with several autoimmune diseases, but their association with thyroid autoimmunity is unclear. We evaluated the association of serum vitamin D levels with the prevalence of autoimmune thyroid disease (AITD).
  
  
  METHODS
  Our cross-sectional study included subjects who underwent routine health checkups, which included assays of serum 25-hydroxy vitamin D3 [25(OH)D3] and anti-thyroid peroxidase antibody (TPO-Ab), as well as thyroid ultrasonography (US) between 2008 and 2012 at the Asan Medical Center. We defined AITD according to the levels of TPO-Ab and US findings.
  
  
  RESULTS
  A total of 6685 subjects (58% male; 42% female) were enrolled for this study. Overall prevalence of TPO-Ab positivity and both TPO-Ab/US positivity were 10.1% (6.3% male; 15.3% female) and 5.4% (2.3% male; 9.7% female) respectively. In female subjects, mean serum 25(OH)D3 levels were significantly lower in the TPO-Ab(+) (22.0 vs. 23.5 ng/mL, p=0.030) and TPO-Ab(+)/US(+) groups (21.6 vs. 23.4 ng/mL, p=0.027) compared with the control group, respectively. According to the levels of serum 25(OH)D3, the prevalence of TPO-Ab positivity (21.2%, 15.5%, and 12.6% in deficient, insufficient, and sufficient group, respectively; p=0.001) and both TPO-Ab and US positivity (14.7%, 9.9%, and 7.1% in deficient, insufficient, and sufficient group, respectively; p<0.001) decreased in female subjects. Interestingly, this pattern was significant only in pre-menopausal women (p=0.003 and p<0.001; respectively), but not in postmenopausal women. Multivariate analysis indicated that the adjusted odds ratios (OR) for AITD among those in the 25(OH)D3-deficient [TPO-Ab(+): OR 1.95, p=0.001; TPO-Ab(+)/US(+): OR 2.36, p<0.001] and -insufficient groups [TPO-Ab(+): OR 1.31, p=0.043; TPO-Ab(+)/US(+): OR 1.50, p=0.017] were significantly increased when compared with the sufficient group.
  
  
  CONCLUSIONS
  The levels of serum vitamin D were significantly lower in pre-menopausal women with AITD. Vitamin D deficiency and insufficiency were significantly associated with AITD in pre-menopausal women.
authors: 1 Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine , Seoul, Korea.
authors: Yun Mi
authors: YM
authors: Choi
authors: Won Gu
authors: WG
authors: Kim
authors: Tae Yong
authors: TY
authors: Kim
authors: Sung Jin
authors: SJ
authors: Bae
authors: Hong-Kyu
authors: HK
authors: Kim
authors: Eun Kyung
authors: EK
authors: Jang
authors: Min Ji
authors: MJ
authors: Jeon
authors: Ji Min
authors: JM
authors: Han
authors: Seung Hun
authors: SH
authors: Lee
authors: Jung Hwan
authors: JH
authors: Baek
authors: Young Kee
authors: YK
authors: Shong
authors: Won Bae
authors: WB
authors: Kim
mesh_terms: D000368:Aged; D001323:Autoantibodies / Q000097:blood; D001324:Autoantigens / Q000276:immunology; D002112:Calcifediol / Q000097:blood* / Q000172:deficiency; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007453:Iodide Peroxidase / Q000276:immunology; D033862:Iron-Binding Proteins / Q000276:immunology; D008297:Male; D008875:Middle Aged; D017697:Premenopause / Q000097:blood* / Q000276:immunology; D013967:Thyroiditis, Autoimmune / Q000097:blood* / Q000000981:diagnostic imaging / Q000276:immunology; D014463:Ultrasonography; D014808:Vitamin D Deficiency / Q000097:blood / Q000276:immunology
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D033862:Iron-Binding Proteins; C056626:thyroid microsomal antibodies; C056658:TPO protein, human; D007453:Iodide Peroxidase; D002112:Calcifediol