Goiter Prevalence, Urinary Iodine Excretion and Household Salt Iodine after 10 years of Salt Iodization in Yazd Province, Iran
Background: Iodine Deficiency Disorders(IDD) are the most important epidemic disorders in the world including Iran. For preventing IDD and its consequences, table salt has been iodized since 1989. At present, this programme has been 10 years old.
Objective: To determine the total goiter rate(TGR) and urinary iodine in 6-11 years old students in Yazd province and related cities after 10 years of salt iodized programme.
Subjects and Methods: A total 4755 primary school students(2948 boys and 1807 girls) aged 6-11 were selected by multistage cluster sampling method from the Yazd province. Thyroid examination and goiter classification were made according to World Health Organization(WHO) guidelines by two trained physicians. Urine sample and household salt was collected from 1/13th of total population. Urinary iodine was determined by a digestion method. Iodine of salt was determined by rapid test kit. Data was analyzed by SPSSWIN software.
Results: TGR of Yazd province was 40.9%(Girls 41.8% and boys 40.3% not significant). Prevalence of goiter grade 1 and grade 2 were 38.6% and 2.3%, respectively. These figurs for girls were 39.1% and 2.7% and for boys were 38.3% and 2% respectively. TGR of Taft, Abarkuh, Khatam, Yazd, Bafgh, Sadugh, Mehriz, Mybod and Ardakan were 43.3%, 41.5% 32.4%, 40.2%, 38.5%, 53.8%, 41.8%, 37.8% and 31.5% respectively. TGR was significantly different among these cities(pv<0.0001).
Overall mean of the urinary iodine was 264±123 µg/l and the corresponding mean in girls and boys were 236±118 µg/l and 281±123 µg/l, respectively which were significantly different(pv=0.001). Mean of urinary iodine in Taft, Abarkuh, Khatam, Yazd, Bafgh, Sadugh, Mehriz, Mybod and Ardakan were 224±146 µg/l, 229±130 µg/l, 332±114 µg/l, 266±122 µg/l, 264±84 µg/l, 291±116 µg/l, 208±125 µg/l, 235±103 µg/l and 279±118 µg/l, respectively (pv=0.02).
In general, 10.5% of study population had urinary iodine concentrations below 100 µg/l, 24.5% were in ideal range(100-200 µg/l) and 65% were higher than 200 µg/l. Approximately 94% of salt samples had iodine.
Conclusion: The study shows that after ten years iodized salt program has decreased the prevalence of goiter and increased urinary iodine. This means that Yazd province is "IDD free" from 2002.