title: Smoking is negatively associated with the presence of thyroglobulin autoantibody and to a lesser degree with thyroid peroxidase autoantibody in serum: a population study.
abstract: BACKGROUND
  Autoimmune thyroid diseases are common and the prevalence of circulating thyroid antibodies (thyroid peroxidase antibody, TPO-Ab and thyroglobulin antibody, Tg-Ab) is high in the population. The knowledge of a possible association between lifestyle factors and circulating thyroid antibodies is limited.
  
  
  OBJECTIVE
  To evaluate the correlation between smoking habits and the presence of circulating TPO-Ab and Tg-Ab.
  
  
  METHODS
  In a cross-sectional comparative population study performed in two areas of Denmark with moderate and mild iodine deficiency, 4649 randomly selected subjects from the population in some predefined age groups between 18 and 65 years were examined. Blood tests were analysed for TPO-Ab and Tg-Ab using assays based on the RIA technique. The participants answered questionnaires, were clinically examined and blood and urine samples collected.
  
  
  RESULTS
  Data were analysed in multivariate logistic regression models. There was a negative association between smoking and the presence of thyroid autoantibodies in serum. This association was observed for the presence of TPO-Ab and/or Tg-Ab, TPO-Ab (without respect to Tg-Ab status), Tg-Ab (without respect to TPO-Ab status) and both antibodies together. The association between smoking and thyroid autoantibodies was stronger for Tg-Ab than for TPO-Ab. There was no association between smoking and TPO-Ab measured alone or between smoking and TPO-Ab when Tg-Ab was included in the model as an explanatory variable.
  
  
  CONCLUSIONS
  Smoking was negatively associated with the presence of thyroid autoantibodies with the strongest association between smoking and Tg-Ab. The study design precludes any conclusions as to the cause of the negative association between smoking thyroid autoantibodies.
authors.affiliation: Department of Endocrinology and Medicine, Aalborg Hospital, Aarhus University Hospital, DK-9000 Aalborg, Denmark.
authors.forename: Inge Bülow
authors.initials: IB
authors.lastname: Pedersen
authors.forename: Peter
authors.initials: P
authors.lastname: Laurberg
authors.forename: Nils
authors.initials: N
authors.lastname: Knudsen
authors.forename: Torben
authors.initials: T
authors.lastname: Jørgensen
authors.forename: Hans
authors.initials: H
authors.lastname: Perrild
authors.forename: Lars
authors.initials: L
authors.lastname: Ovesen
authors.forename: Lone Banke
authors.initials: LB
authors.lastname: Rasmussen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D005260:Female; D006801:Humans; D007453:Iodide Peroxidase / Q000276:immunology*; D008019:Life Style; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D012907:Smoking / Q000453:epidemiology*; D013967:Thyroiditis, Autoimmune / Q000453:epidemiology* / Q000276:immunology*
chemical_list: D001323:Autoantibodies; C006606:anti-thyroglobulin; D007453:Iodide Peroxidase