title: Hashimoto's thyroiditis: similar and dissimilar characteristics in neighboring areas. Possible implications for the epidemiology of thyroid cancer.
abstract: BACKGROUND
  Medical centers worldwide report an increased frequency of Hashimoto's thyroiditis (HT) and thyroid cancer (TC), two environmentally influenced diseases. In Sicily, data on HT are available for the province of Messina (1975-2005); data on TC are available for the whole island (2002-2004), with the volcanic province of Catania having the highest incidence.
  
  
  OBJECTIVE
  To replicate in Catania, on comparable years, the HT data of Messina. DESIGN METHODS SETTING: Review of the clinical records of patients in years 1995-2005 to compare presentation and yearly changes of HT. During 1995-2005, records were computer stored in the Endocrine Divisions of the University Hospitals of Catania and Messina, two tertiary referral centers.
  
  
  RESULTS
  Catania is outnumbered by Messina (742 vs. 3,409 HT patients). Similar were the linear increase in the yearly number of HT patients, rates of thyroid dysfunctions though with different proportions of subclinical and overt hypothyroidism, and rates of positiveness for TgAb or TPOAb. Different were age and its yearly trend; gender distribution and rates of the sonography variants, though yearly trends were similar.
  
  
  CONCLUSIONS
  The HT epidemics is smaller in Catania, with changes in presentation overlapping partially those in Messina. Whatever environmental factors might be involved, they (and/or their intensity) were not necessarily the same in these provinces. Intriguingly, the expected number of TC in HT patients with thyroid nodules in Catania is congruent with that of the general population of this province, but it is far less than in the Messina province. Thus, TC and HT incidences could be influenced by distinct environmental factors.
authors.affiliation: Endocrinology Division, Department of Clinical and Molecular Biomedicine, University of Catania Medical School, Garibaldi-Nesima Hospital, Catania, Italy.
authors.forename: Adele
authors.initials: A
authors.lastname: Latina
authors.forename: Damiano
authors.initials: D
authors.lastname: Gullo
authors.forename: Francesco
authors.initials: F
authors.lastname: Trimarchi
authors.forename: Salvatore
authors.initials: S
authors.lastname: Benvenga
mesh_terms: D000328:Adult; D001323:Autoantibodies / Q000097:blood; D015331:Cohort Studies; D015981:Epidemiologic Factors; D005260:Female; D050031:Hashimoto Disease / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D007453:Iodide Peroxidase / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012802:Sicily / Q000453:epidemiology; D013954:Thyroglobulin / Q000276:immunology; D013961:Thyroid Gland / Q000000981:diagnostic imaging; D013964:Thyroid Neoplasms / Q000453:epidemiology*; D014463:Ultrasonography
chemical_list: D001323:Autoantibodies; D013954:Thyroglobulin; D007453:Iodide Peroxidase