Non-palpable thyroid nodules in a borderline iodine-sufficient area: Detection by ultrasonography and follow-up

Thyroid ultrasonography was performed in 482 subjects, free of known thyroi d disease and living in a borderline iodine-sufficient urban area, to asses s the prevalence of non-palpable thyroid nodules and evaluation their evolu te during a 3-yr follow-up. The mean (+/- SD) thyroid volume in the whole s tudy group was 10.9 +/-3.7 ml and was higher in males (12.9 +/-3.6 ml) than in females (9.2 +/-2.9 ml) (p <0.0001). Thyroid volume was correlated with body surface, height and weight, while no correlation was present with lea n and fat body mass. Goiter was found in 5/256 females and in 13/226 males. Thyroid nodules were found in 27/482 subjects (18 females, 9 males). Singl e nodules were found in 17/464 subjects (3.66%) with a thyroid gland of nor mal volume and in 4/18 subjects (22.2%) with goiter (chi (2)=10.21; p=0.001 ). Multiple nodules were found in 3/464 subjects (0.6%) with a thyroid of n ormal volume and in 3/18 (16.6%) subjects with goiter (chi (2)=24.31; p <0. 0001). The prevalence of thyroid nodules was significantly higher in female s > 35 yr than in those < 34 yr (chi (2)=7.47; p=0.0062). A significant inc rease (> 30%) of nodular volume was found in 5 subjects, while an increased number of nodules was found in 8. In conclusion, thyroid ultrasonography r eveals the presence of thyroid nodules in a significant proportion of appar ently thyroid disease-free subjects living in a borderline iodine-sufficien t urban area. Incidentally discovered thyroid nodules are associated with g oiter and are likely to progress in volume and number. (C) 2001, Editrice K urtis.