Eighteen Years of Continuously Sustained Elimination of Iodine Deficiency in the Islamic Republic of Iran: The Vitality of Periodic Monitoring

Background: Two decades ago the Islamic Republic of Iran was among countries most severely affected by iodine deficiency. Iran has since achieved great success in the control and elimination of iodine deficiency disorders (IDDs) following the national salt iodization program, initiated in 1989. The aim of the study was to evaluate the effectiveness of sustained consumption of iodized salt by Iranian households and the current status of iodine nutrition in all 30 provinces of Iran. Methods: Goiters-measured by palpation-and urinary iodine concentration of children were assessed. In this descriptive cross-sectional study, 36,000 schoolchildren (18,000 girls and 18,000 boys), aged 8-10 years, were randomly selected, from October 2007 to February 2008, from 30 provinces of the country. Goiter prevalence and urinary iodine excretion in schoolchildren and the iodine content of salt at household, factory, and distribution site levels were measured. Results: The goiter rate in the country was 6.5% (6% grade 1 and 0.5% grade 2), and the weighted goiter rate was 5.7%. The total goiter rate in Hamedan, Zanjan, Kermanshah, Mazandaran, and Gilan provinces was over 10%. The median urinary iodine was 140 mu g/L. Urinary iodine levels of 20-50, 50-99, and >= 100 mu g/L were noted in 15.3%, 19.8%, and 64.9% of the samples, respectively. In four provinces, the median urinary iodine was lower than 100 mu g/L. The mean (+/- SD) and median salt iodine values were 23.2 (+/- 13.8) and 34.7 ppm, respectively, at the production level, and 32.4 (+/- 14.7) and 32.3 ppm, respectively, at the distribution level. Ninety-eight percent of households consumed iodized salt, 58% of households had appropriate salt storage, and 27% of the household salts contained < 20 ppm. Conclusions: Iran has achieved much in the development of universal salt iodization strategy and elimination of IDDs and currently meets all criteria for sustainable elimination of iodine deficiency. However, the lack of adequate iodine nutrition in some provinces necessitates special attention and proper monitoring.