MONITORING OF GOITER AND URINARY IODINE EXCRETION IN 6-10 YEAR OLD SCHOOL CHILDREN IN AHWAZ (2002-2003)

Simple goiter is one of the most prevalent endocrine disease all over the world. Before iodine supplementation in 1990, Khuzestan province was an endemic area for goiter in Iran. This study was performed in 2002-2003, about 13 years after iodine suplementation, to determine the prevalence of goiter and urinary iodine excretion among 1800 school children (6-10 years old) in Ahwaz. The subjects were chosen by cluster sampling. Physical examination and goiter staging according to WHO criteria was done by 4 medicals student trained in endocrinology department. A questionnaire included: age, sex and level of iodized salt consumption, was filled out for each person. Urinary iodine excretion (by digestion method), was assessed in 75 person by random sampling. In addition, thyroid function tests which included: T3, T4, T3RU by RIA and TSH and serum ferritin by IRMA method were assessed randomly in this selected population. The results showed that 52.5% of the subjects were males and 47.5 were females. 712 school children (39.6%) had goiter (17.3% stage Ia, 18.4% Ib, 3.7% stage II). There was no case of stage III goiter. Prevalence was higher in girls (43.5% versus 35.9%) (P<0.01). 90.4 % of study group consumed iodized salts. The mean urinary iodine excretion was 31g/dl in normal children, 26g/dl in person with stage Ia goiter, 21g/dl in Ib goiter and 14g/dl in stage II goiter. Urinary iodine was significantly higher in normal children than those with goiters stage Ib or II. 9.3% of studied persons had urinary iodine excretion lower than 10g/dl, 18.7% between 10-20g/dl and 72% had urinary iodine more than 20g/dl. The mean T4, T3, T3ru and TSH in normal and goiterous persons were 7.7 versus 8.02g/dl, 184 versus 186ng/ml, 32% versus 33% and 2.5 versus 3.4miu/ml respectively. Only TSH showed significant difference between normal and goiterous persons (P<0.01). There was no significant difference in the mean serum ferritin concentration between normal and goiterous children (29 versus 23g/dl). These findings suggest that after 13 years of consumption of iodized salt, more than 90% of studied persons had urinary iodine excretion more than 10g/dl, and goiter still has a high prevalence of 39.6%, therefore, other goitrogen factors should be sought for in this area.