Ultrasonographic evaluation of the thyroid gland volume among 8-15-year-old children in Isfahan, Iran

BACKGROUND: Local reference data are needed in the screening of children for thyroid enlargement. We determined the thyroid gland volume using the ultrasonography (US) in schoolchildren of Isfahan, Iran. MATERIALS AND METHODS: A total of 360 schoolchildren (59% girls) aged 8-15 years who met the study criteria were entered the study. Clinical grading of goiter was performed by an endocrinologist according to the World Health Organization (WHO) classification. Then, a single expert radiologist performed thyroid volume measurement using a portable ultrasound device. Urinary iodine (UI) concentration was checked in 36 randomly selected cases. RESULTS: On physical examination, 327 (91%), 32 (8.8%) and 1 (0.2%) subjects were classified as normal, borderline and goiter Grade 2. Mean thyroid volume measured by US was 1.46 ± 0.70 ml. Thyroid volume in boys was significantly higher than girls (1.58 ± 0.67 ml vs. 1.38 ± 0.71 ml; P = 0.009). Thyroid volume was positively correlated with the clinical grade of the goiter (r = 0.30, P < 0.001) and with age (r = 0.25, P < 0.001). Both median and 95(th) percentile of thyroid volume of our subjects was lower than the reference values reported by WHO. Median of UI was 16.90 μg/dl. UI was not correlated with thyroid volume (r = 0.12, P = 0.46). CONCLUSION: The thyroid size in Isfahanian schoolchildren is lower than the reference values reported by WHO. These data could be used in determining local reference in the screening of children for thyroid enlargement.