Goiter in Thai schoolchildren: study in Hat Yai, southern Thailand

Examination for goiter was performed in 6,035 schoolchildren (2,899 girls, 3,136 boys), aged 8-17 years, from primary and secondary schools in Hat-Yai municipality, Songkhla province. Goiter was detected in 355 children (combined prevalence 6%; 232 or 8% in girls, 123 or 4% in boys). Of the 355 children with goiter, 214 (60%; 148 girls, 66 boys) participated in the study, and had blood drawn for free thyroxine (FT4), triiodothyronine (T3), thyroid stimulating hormone (TSH), and thyroid antibodies. All had urine collected for iodine excretion. The diagnoses of goiter were as follows: simple goiter in 192 (89.8%; 129 girls, 63 boys); juvenile autoimmune thyroiditis in 18 (8.4%; 16 girls, 2 boys); Graves' disease in 2 girls (0.9%); thyroid adenoma in 1 boy (0.45%), and ectopic thyroid in 1 girl (0.45%). Acquired hypothyroidism was found in 4 out of 18 children with juvenile autoimmune thyroiditis (22.2%). Iodine deficiency disorder was not evident in children examined shown by high urinary iodine excretion of more than 50 mcg/gm creatinine (mean 298, range 70-630). In conclusion, simple goiter is a common occurrence in children and adolescents in Southern Thailand. Juvenile autoimmune thyroiditis should be identified and differentiated from simple goiter as it is the most common cause of acquired hypothyroidism. Iodine deficiency is not evident in Southern Thailand, at least in the urban areas of a large city.