title: The association of cigarette smoking with serum TSH concentration and thyroperoxidase antibody.
abstract: BACKGROUND
  Although several studies have found an association between tobacco smoking and thyroid disorders such as Graves' disease, Graves' ophtalmopathy, goiter and thyroid multi nodularity, the effect of smoking on thyroid function is controversial.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the association between smoking and serum TSH concentration and the presence of thyroperoxidase antibody (TPO Ab) in Tehranian adults.
  
  
  METHODS
  In this cross sectional community based survey, 1,581 randomly selected subjects with no history of thyroid disorders were studied within the framework of Tehran Lipid and Glucose Study. Serum TSH and TPOAb were measured in a fasting serum sample. Weight and height were measured and BMI was calculated. Smokers were classified into ever and never smokers based on the declaration of participants.
  
  
  RESULTS
  Mean Ln TSH values in the ever smoker (0.36±0.82) was significantly lower than the never smoker (0.6±0.82) group (p<0.001) even after adjustment for age and BMI. The odds ratio for hypothyroidism (TSH>5.8) was 0.4 in the ever smoker group compared to the never one (odds ratio 0.4, 95% CI=0.2-0.8). The frequency of positive TPOAb in never smokers was significantly higher than ever smokers (%13.5 vs. % 6.7, p<0.001).
  
  
  CONCLUSIONS
  The results suggest that smoking is associated with decreased serum TSH concentrations, lower risk of hypothyroidism and possibly with a lower frequency of thyroid auto immunity.
authors.affiliation: Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: L
authors.initials: L
authors.lastname: Mehran
authors.forename: A
authors.initials: A
authors.lastname: Amouzgar
authors.forename: H
authors.initials: H
authors.lastname: Delshad
authors.forename: F
authors.initials: F
authors.lastname: Azizi
mesh_terms: D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D002318:Cardiovascular Diseases / Q000097:blood / Q000209:etiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007453:Iodide Peroxidase / Q000276:immunology*; D007492:Iran / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D015995:Prevalence; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects / Q000097:blood* / Q000453:epidemiology / Q000276:immunology*; D013972:Thyrotropin / Q000097:blood*
chemical_list: D001323:Autoantibodies; D013972:Thyrotropin; D007453:Iodide Peroxidase