Increased goiter prevalence in schoolchildren of Isfahan despite long-term iodine sufficiency

Abstract

Iodine Deficiency (ID) was for years considered a contributing factor for endemic goiter in Iran. The present study was conducted to assess the goiter prevalence and iodine status in schoolchildren of Isfahan 16 years after the initiation of salt iodization in Iran. 2331 schoolchildren, aged 6-13 years were selected by multistage random sampling. Thyroid size was estimated in each child by inspection and palpation and was graded according to the criteria recommended by WHO. Urinary Iodine Concentration (UIC) was also measured. Overall, 32.9% of the 2331 students had goiter. 4.6% of them were classified as goitrous grade 2. The median UIC was 195.5 microg/l (Range: 10-580 microg/l). 15.8% of total samples had iodine excretion level below 100 microg/l and 3.7% had iodine level below 50 microg/l. UIC in nongoitrous and goitrous children was (mean+/-SD) 220.91+/-119.44 microg/l and 220.16+/-114.64microg/l, respectively (p= 0.949). According to the present study there is no biochemical ID and the iodine intake of the total population is adequate. Goiter prevalence has decreased significantly after the new legislation, nevertheless it is still a public health problem in this region. The data suggest that other goitrogens, micronutrient deficiencies and thyroid autoimmunity may be operative and must be investigated in Isfahan schoolchildren.