The investigation of effects of fluorosis on thyroid volume in school-age children.

AIM To compare the urine iodine, fluoride, and to measure thyroid volumes in 10-15-year-old children using ultrasonography, a gold standard in evaluating thyroid volume. METHODS A total of 261 children were enrolled into the study group from the 4-8th grades of 3 different primary schools, which were in the zone with high fluoride levels. The control group was formed by enrolling 298 children from the 4-8th grades of only one primary school. Age, gender, height, and weight values were recorded for the children. The urine iodine, fluoride, and thyroid volumes were measured with ultrasonography in 10-15-year-old children with fluorosis and controls and compared between two groups. RESULTS The mean urine fluoride level was 0.48±0.24 mg/L in the study group and 0.22±0.17 mg/L in the control group (p < 0.001). The mean urine iodine level did not differ between two groups. The mean total thyroid volume was 8.60±3.11 mL and 8.73± 2.75 mL in the study and control group, respectively. The groups were also compared according to the echobody index, and the score was 6.94±2.14 ml/m² in the study group and 6.48±1.53 ml/m² in the control group (p=0.003). Mean thyroid volumes did not differ between two groups. However, the echobody index in the study group was higher than in the control group. CONCLUSION A relation between fluoride concentration and thyroid gland with ultrasonographic examination was firstly evaluated, and it was concluded that fluoride affected thyroid gland although it was weakly significant. After puberty, echobody index in subjects with fluorosis was markedly high. Based on our results, we thought that fluorosis increases thyroid volume in children with fluorosis after puberty.