[The results of thyroid ultrasound examination in randomly selected schoolchildren]

Iodine deficiency is an actual problem of public health and mostly manifests as enlargement of the thyroid (goiter).

The aim of the study was to determine the prevalence of goiter using different evaluation criteria and to establish the relationship between changes in thyroid volume and dimensions of the body.

Thyroid palpation and ultrasound examination were performed in 310 (7-11-year-old) randomly selected schoolchildren from two Lithuanian nearby small towns (Birzai and Rokiskis) in the district with lowest urinary iodine excretion (5.4 and 4.5 microg/dl). The size of thyroid gland was determined by inspection and palpation using the World Health Organization criteria. All children were examined ultrasonographically; thyroid volume was assessed by two criteria: F. Delange (1997) and M. B. Zimmermann (2004).

There were no differences in means and medians of age and all body parameters (height, weight, body surface area, body mass index) in boys and girls of the same age. Higher means and medians of the body surface area in all age groups were found in Birzai as compared to Rokiskis (p<0.05). Comparing body mass index of all investigated schoolchildren with upper limits (97th percentile) of body mass index of normal British children, no statistically significant difference in the prevalence of obesity between towns was observed (1.9% - in Rokiskis, 5.0% - in Birzai; p>0.05). Grouping the children according to age revealed a higher prevalence of goiter in Birzai as compared to Rokiskis (88% vs. 63%, respectively, according to M. B. Zimmermann and 25% vs. 10%, respectively, according to F. Delange; p<0.05). There was no significant difference in the prevalence of goiter between the towns when children were grouped by body surface area. In all groups by age and body surface area, the mean thyroid volume exceeded 97th percentile by M. B. Zimmerman and did not exceed by F. Delange.

The prevalence of goiter, assessing the thyroid volume in 7-11-year-old children by the different criteria, is significantly different. We recommend using the criteria based on body surface area in order to evaluate the constitutional characteristics of individual child's development.