title: Thyroid incidentaloma in Isfahan, Iran - a population-based study.
abstract: BACKGROUND
  Thyroid nodules not detected in palpation but diagnosed following a radiological procedure or during surgery are called thyroid incidentalomas. We designed this study to investigate the prevalence of sonographic thyroid incidentaloma in Isfahan, Iran, for the first time.
  
  
  METHODS
  By a multistage cluster sampling method, 2523 adults were selected randomly. From this group, 2045 had normal thyroid examination. 234 out of the 2045 were selected randomly for thyroid sonography. Thyroid stimulating hormone (TSH), urinary iodine concentrations (UIC) and antithyroid antibodies were measured.
  
  
  RESULTS
  The prevalence of thyroid incidentaloma was 13.2% [Confidence interval (CI) 95% = 8-18]. The average age of subjects with and without incidentaloma was 46.1 (12.4) and 38.4 (12.1), respectively (P = 0.002). It was more prevalent in females than in males (19% vs. 10%) [Odds ratio (OR) = 2.59, CI 95% = 1.17-5.76, P value (P) = 0.01]. Median UIC in the incidentaloma group (14 microg/dl) was significantly lower than in the group of subjects without nodules (20 microg/dl) (OR = 0.9, CI 95% = 0.91-0.99, P = 0.02). There was no difference in the levels of TSH and antithyroid antibodies between the two groups (P > 0.05). Mean diameter of nodules was 8.14 (3.43) mm.
  
  
  CONCLUSIONS
  The prevalence of thyroid incidentaloma was 13.2% in Isfahan. It was higher in females than males and increased with age.
authors.affiliation: Isfahan Endocrine and Metabolism Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Jafary
authors.forename: Ashraf
authors.initials: A
authors.lastname: Aminorroaya
authors.forename: Massoud
authors.initials: M
authors.lastname: Amini
authors.forename: Atoosa
authors.initials: A
authors.lastname: Adibi
authors.forename: Mehri
authors.initials: M
authors.lastname: Sirous
authors.forename: Ehsan
authors.initials: E
authors.lastname: Roohi
authors.forename: Mohsen
authors.initials: M
authors.lastname: Mostafavi
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015994:Incidence; D033162:Incidental Findings; D007455:Iodine / Q000652:urine; D007492:Iran / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010298:Parity; D011247:Pregnancy; D013964:Thyroid Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000378:metabolism; D016606:Thyroid Nodule / Q000175:diagnosis / Q000453:epidemiology / Q000378:metabolism; D013972:Thyrotropin / Q000378:metabolism
chemical_list: D013972:Thyrotropin; D007455:Iodine