Thyroid incidentaloma in Isfahan, Iran - a population-based study.
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.
Jafary
Fatemeh
F
Isfahan Endocrine and Metabolism Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
Aminorroaya
Ashraf
A
Amini
Massoud
M
Adibi
Atoosa
A
Sirous
Mehri
M
Roohi
Ehsan
E
Mostafavi
Mohsen
M
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
D013972:Thyrotropin; D007455:Iodine