Prevalence of Goiter and Urinary Iodine in 6-11 Years Old Students of Yazd in the Year 2002

Iodine deficiency disorders (IDD) are among the most important epidemic disorders in the world and also in our country. The surveillance of IDD may be implemented to: assessing the prevalence of IDD, identifying the high risk areas for intervention and monitoring and evaluateing IDD control programmes, as salt iodized programme. The aim of this study was to determine the total goiter rate (TGR), urinary iodine in 6-11 years old students in Yazd city 10 years after iodized salt program. In this study, 1989 primary school students (1367 boys and 622 girls) aged 6-11 were selected by multistage “probability proportionate to size” cluster(PPS) sampling method in Yazd city. Thyroid examination and goiter classification were made according to WHO standard protocol by two trained physicians. Urine and household salt samples were collected from one-thirteenth of the total population (140 individuals). Urinary iodine was determined by digestion method. Salt iodine was determined by rapid test kit. TGR of Yazd city was 40.2% (Girls 41% and boys 39.9%). Prevalence of goiter grade 1 and grade 2 were 38.7% (39.2% for girls and 38.5% for boys), and 1.5% (1.8% for girls and 1.4% for boys), respectively. The rate of goiter was not significant between the two sexes). Age specific TGR at 6-6.9,7-7.9, 8-8.9, 9-9.9 and 10-11 age groups were 39%, 37.7%, 42%, 40% and 42.1%, respectively. Age spesific goiter grade 1 in this age groups were 38.7%, 35.2%, 40.5%, 38.8% and 39.9%, respectively. Age spesific goiter grade 2 in this age groups were 0.3%, 2.3%, 1.5%, 1.3% and 2.2%, respectively. TGR in this age groups were not significant(p=0.3). The mean of the urinary iodine was 258±122 μ g/l (244 ± 115 and 265 ± 125 μ g/l) in girls and boys respectivly, which were not significantly different. In general, 10% of Yazd study population had urinary iodine concentrations less than 100 μ g/l, 26.4% were in adequate range (100-200 μ g/l), 63.6% were higher than 200 μ g/l the urine iodine 40.7% of the 3rd group were higher than 300 μ g/l. In general, 3.2% of household salt samples did not contain iodine, 5.6% had 15ppm level, and 91.2% had above 30ppm level. Thus, approximately 96.8% of salts had iodine. The results of this study indicated that TGR, specially goiter grade 2, had significantly decreased in Yazd, and according to urinary iodine status, not only the mean of urinary iodine was elevated, but also was higher than ideal range of WHO. Thus, according to this index, it can be concluded that since the year 2002, Yazd city is IDD free.