Prevalence of palpable thyroid nodule in Isfahan, Iran, 2006: a population based study

This cross-sectional study enrolled 2 523 of adult general population (age > 20 years) of Isfahan city. History taking and thyroid exam was performed by seven trained general practitioners. The concentration of TSH was measured in all, TgAb and TPOAb in approximately one in six and urinary iodine concentration in one fourth of them, randomly. We recalled people with any suspicious abnormality in thyroid exam or whose TSH levels were not normal at present or past. They were re-visited by an endocrinologist to confirm or rule out the diagnosis and second serum sample was obtained to measure T4, T3, T3RU and TSH.

Thyroid nodule was identified in 62 (17 men and 45 women) out of 2 523 participants (2.5%; 95% CI: 2-3). Single and multiple nodules were found in 56 (2.2%; 95% CI: 1-2.5) and 6 (0.24%; 95% CI: 0.07-0.5) out of 2 523 persons, respectively. The prevalence of nodule was higher in females (3.5%) than in males (1.3%) (OR=2.72, 95% CI, 1.53-5.06, P=0.001). It was significantly higher in patients older than 35 years in comparison with younger people (3.3% vs. 1.3%; OR=2.5; 95% CI, 1.3-4.7; P=0.002).

The prevalence of thyroid nodule in our study is less than what has been reported in other countries. It is due to lower prevalence in female population. Its prevalence in males is similar to other studies. It seems that geographical and racial differences or higher prevalence of deeper location of some nodules in female Isfahani population could explain this finding.