Prevalence of goiter among schoolchildren from Gorgan, Iran, a decade after national iodine supplementation: Association with age, gender, and thyroperoxidase antibodies

Background: One decade after universal salt iodization in Iran, goiter prevalence, urinary iodine concentration (UIC) and thyroperoxidase antibody (TPOAb) values were assessed among schoolchildren in Gorgan, Iran. Methods: From 2003-2004, 500 girls and 900 boys aged 7-11 yr were evaluated for goiter by palpation. UIC was measured in 183 randomly-selected goitrous children. Serum TSH, T-4, and TPOAb were measured in 53 goitrous and 30 non-goitrous children with adequate UIC. Results: Goiter was detected in 370 (26.4%) children. Goiter was present in 31% of girls and 17% of boys age 9 (p < 0.01 2); 37% of girls and 20% of boys age 10 (p < 0.003); and 52% of girls and 19% of boys age 11 (p < 0.0001). Median (range) UIC for all goitrous children sampled was 190 (20-600) mu g/l; 220 (30590) in boys and 170 (20-600) in girls (p=0.001). Eight point seven percent of goitrous children and 22% of goitrous girls aged 10-11 had UIC < 100 mu g/l, while 47% of the goitrous children had UIC200 mu g/ I. TPOAb was present in 52.8% of goitrous children and 10% of non-goitrous children (p=0.0001). TPOAb was present in 53.9% of 10-11 and 22.7% of 7-9 yr old goitrous and non-goitrous children (p=0.003) with adequate UIC. Median (range) TSH was 2.9 (0.3-10.9) mIU/I in TPO-positive and 1.8 (0.5-4.1) in TPO-negative children (p=0.001). Conclusions: Gorgan, Iran, is an iodine-sufficient area and almost half of schoolchildren have more than adequate UIC. TPOAb is associated with endemic goiter. Despite sufficient UIC overall, some school-aged girls remain at risk of iodine deficiency.