OBJECTIVE: To evaluate the success of the Iranian Iodine Deficiency Disorders Committee in achieving World Health Organization (WHO) goals for reducing the prevalence of goiter in children by adding iodine to table salt beginning in 1989. METHODS: In 1997, 8,000 male and female 6- to 18-year-old students were selected by cluster sampling in schools of Isfahan. Their thyroids were examined by four endocrinologists, and goiter was staged on the basis of the WHO classification. As an index of iodine consumption, urinary iodine concentrations were measured in 3,000 students. RESULTS: Goiter was observed in 62% of the students. Of the overall study group, 94% had sufficient iodine consumption (urinary iodine concentration of 10.0 microg/dL or more). Of those students who had sufficient iodine intake, 63.2% had goiter. Of the 6% of students with iodine deficiency, 5% had mild, 0.9% had moderate, and only 0.1% had severe iodine deficiency. Goiter was absent in half of the students with severe iodine deficiency. The prevalence of goiter in 6- to 10-year-old children was 65%. CONCLUSION: Despite sufficient iodine intake, the prevalence of goiter is still high in Isfahan City. Apparently, either this high prevalence has no relationship to iodine deficiency and possibly other unknown goitrogens are involved in the pathogenesis of goiter in Isfahan or the period of iodine intake has been too brief to affect thyroid sizes. Inasmuch as goiter prevalence is also high in the 6- to 10-year-old children, who have had iodized salt available for most of their lives, the second option is less probable. Another possibility is an increased rate of autoimmune thyroid diseases (because of iodine repletion) that resemble goiter during their early stages.
OBJECTIVE: To evaluate the success of the Iranian IodineDeficiency Disorders Committee in achieving World Health Organization (WHO) goals for reducing the prevalence of goiter in children by adding iodine to table salt beginning in 1989. METHODS: In 1997, 8,000 male and female 6- to 18-year-old students were selected by cluster sampling in schools of Isfahan. Their thyroids were examined by four endocrinologists, and goiter was staged on the basis of the WHO classification. As an index of iodine consumption, urinary iodine concentrations were measured in 3,000 students. RESULTS:Goiter was observed in 62% of the students. Of the overall study group, 94% had sufficient iodine consumption (urinary iodine concentration of 10.0 microg/dL or more). Of those students who had sufficient iodine intake, 63.2% had goiter. Of the 6% of students with iodine deficiency, 5% had mild, 0.9% had moderate, and only 0.1% had severe iodine deficiency. Goiter was absent in half of the students with severe iodine deficiency. The prevalence of goiter in 6- to 10-year-old children was 65%. CONCLUSION: Despite sufficient iodine intake, the prevalence of goiter is still high in Isfahan City. Apparently, either this high prevalence has no relationship to iodine deficiency and possibly other unknown goitrogens are involved in the pathogenesis of goiter in Isfahan or the period of iodine intake has been too brief to affect thyroid sizes. Inasmuch as goiter prevalence is also high in the 6- to 10-year-old children, who have had iodized salt available for most of their lives, the second option is less probable. Another possibility is an increased rate of autoimmune thyroid diseases (because of iodine repletion) that resemble goiter during their early stages.