Introduction: The aim of this study was to investigate the current status of sonographic characteristics of thyroid nodules in Isfahan, a previously iodine deficient area in central Iran.

Material and methods: In a cross-sectional study conducted in 2006, 2523 adult people (age > 20 years) were selected by a multistage clustering sampling method. Of these people, 263 volunteered persons were underwent sonographic evaluation. Thyroid examination was done by two expert sonographers. Serum T(3), T(3), T3RU, TSH, TPO Ab and Tg Ab, and urinary iodine were measured.

Results: Forty-six per cent of the 263 people were women. Their mean age was 35.5 years with a range of 20-64 years. Median urinary iodine was 19.4 microg/dL. The prevalence of thyroid nodules on sonography was 22.4% in the whole group; 30% in women and 16.3% in men (OR = 2.2, P = 0.01). The prevalence of thyroid nodules increased with age (P = 0.006). The prevalence of thyroid nodules was higher in hypothyroid people than in euthyroid people (35.1% v. 20.5%, OR = 2.1, P = 0.04). Neither urinary iodine nor autoantibody concentrations correlated with the prevalence of thyroid nodules in sonography.

Conclusions: The prevalence of thyroid nodule by sonography is still high despite relatively normal urinary iodine in this population.

Keywords: nodular goiter, autoimmunity, sonography, iodine, Iran