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Brazilian Journal of Medical and Biological Research
On-line version ISSN 1414-431X
LISBOA, H.R.K. and GROSS, J.L.. Ultrasonographic determination of goiter prevalence in southern Brazilian schoolchildren. Braz J Med Biol Res [online]. 2002, vol.35, n.10, pp. 1147-1152. ISSN 1414-431X. http://dx.doi.org/10.1590/S0100-879X2002001000006.
The aim of the present study was to estimate the prevalence of goiter in schoolchildren in a formerly iodine-deficient region in southern Brazil by assessing the relationship between body surface area (m2) and thyroid volume (ml) measured by ultrasonography. A population-based sample of 1,094 randomly selected schoolchildren (6 to 14 years; 556 boys and 538 girls) underwent clinical evaluation. A total of 119 (10.9%) children were diagnosed with goiter upon clinical examination according to WHO criteria (grade Ia: 65, grade Ib: 24, grade II: 29, grade III: 1). Of these, 85 underwent ultrasonography. In order to ascertain the absence of goiter in the 975 schoolchildren with a negative result upon clinical examination, one of ten children was randomly selected for ultrasonography. Sixty-two children agreed to be submitted to the exam. Thus, 147 schoolchildren were evaluated by ultrasonography (7.5-MHz transducer). Goiter was considered to be present when the thyroid volume:body surface area index was >6.2 ml/m2. The estimated prevalence of goiter if all schoolchildren had been submitted to thyroid volume measurement by ultrasound was 7.2%; it was higher in the lower socioeconomic class (8.2%) than in the upper (7.8%) and middle classes (6.5%). In conclusion, the prevalence of goiter in schoolchildren of this region was higher than in other iodine-sufficient areas, especially in lower socioeconomic classes. Goiter in this region may be associated with naturally occurring goitrogens that operate more intensively among less privileged individuals.
Keywords : Goiter; Prevalence; Thyroid gland; Ultrasonography.