Thyroid volume in Turkish school-age children living in an iodine-sufficient region.

Objectives: We aimed to obtain local normative data on thyroid volume evaluated by ultrasonography and iodine status by measuring urine iodine levels in school-age children living in Aydın province.

Methods: In this cross-sectional study, a sample comprising 1,553 cases was meticulously selected from a total cohort of 170,461 children aged 6-17, drawn from 21 distinct educational institutions located within the Aydın region, as participants in the investigation. Those with a known chronic disease or thyroid disease were excluded from the study. The children underwent physical examinations and ultrasonography imaging of the thyroid gland, and urine samples were collected to measure urinary iodine concentration (UIC).

Results: The median UIC was 189.5 (IQR=134.4) μg/L, which was optimal according to WHO criteria. Thyroid volume was found to be 4.6 (IQR=3.5) mL in girls and 4.2 (IQR=4.0) mL in boys (p=0.883). The thyroid volumes in our study were found to be smaller when compared to the WHO. According to WHO age and body surface area criteria, thyroid volume was over 97 % in 0.9 % (n=15) of cases. Thyroid volume was found to have a positive correlation with age, height, weight, body mass index (BMI), and body surface area (BSA) in both genders (p<0.001). However, there was no significant correlation between thyroid volume and UIC.

Conclusions: This cross-sectional study provides normative data on thyroid volume and iodine status in school-age children in iodine-sufficient population, revealing a low prevalence of goiter and correlations between thyroid volume and anthropometric measures.