Goiter persistence after iodine replenishment, the potential role of selenium deficiency in goitrous schoolchildren of Semirom, Iran.

BACKGROUND: Despite long-standing iodine supplementation in Iran, the prevalence of goiter remains high in some areas. This suggests other nutritional deficiencies may be considered as responsible factors of goiter persistence. Therefore, we assessed the prevalence of selenium deficiency in children living in a mountainous area in Iran to evaluate its correlation with goiter. METHODS: In this cross-sectional study, 1828 students from the 108 primary schools of urban and rural areas of Semirom in central Iran were selected by multistage random cluster sampling. After obtaining written consent from their parents, the children were examined for goiter grading. Grade 2 goitrous children (108 cases) were compared with non-goitrous children (111 children) as control group for serum selenium concentration. RESULTS: Overall, 36.7% of 1828 students had goiter. The mean and median urinary iodine excretion level was 19.3 and 18.5 mug/dl respectively. This was within normal limits. Of 219 evaluated cases, 109 children had selenium deficiency. Mean serum levels of selenium in the goitrous and control groups were 62.7 mug/l and 60.8 mug/l, respectively (p=0.42). There was a borderline significant difference of the goiter prevalence in selenium deficient and selenium sufficient subjects (40.8% vs. 54.3%, p=0.037). Twelve children had clinical or subclinical hypothyroidism. The mean (SD) serum selenium concentration of euthyroid and hypothyroid students were 61.9 (17.2) mug/l and 66.4 (11.9) mug/l respectively (p=0.35). CONCLUSION: In the area studied, selenium deficiency cannot explain high prevalence of goiter and other responsible factors should be investigated. Selenium deficiency may also have mild borderline significant protective effects on thyroid function and goiter.

Effects of iodized salt consumption on goiter prevalence in Isfahan: the possible role of goitrogens.

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.

Peripheral neuropathy in type 2 diabetes mellitus in Isfahan, Iran: prevalence and risk factors.

BACKGROUND: To estimate the prevalence and risk factors of peripheral neuropathy (PN) in people with type 2 diabetes mellitus. METHODS: A total of 810 patients with type 2 diabetes (289 men and 521 women) from Isfahan Endocrinology and Metabolism Research Centre outpatient clinics, Iran, were examined. Part of examination included an assessment of neurological function including neuropathic symptoms and physical signs and nerve conduction velocity. RESULTS: The prevalence of PN was 75.1% (95% confidence interval 72.1, 78.0). PN was associated with age, proteinuria, and duration of diabetes, insulin-treatment, and presence of any retinopathy and ischaemic heart disease (IHD). The age-adjusted prevalence rate of PN was 78% higher among patients with IHD, 64% higher among patients with any retinopathy, 66% higher among insulin-treated type 2 diabetes, and it was greater with duration of diabetes. Using a stepwise binary logistic regression model, age, duration of diabetes and proteinuria were significant independent predictors of PN. CONCLUSION: Peripheral neuropathy is a common complication in this population of Iranian type 2 diabetic patients. It increases with age, duration of diabetes and proteinuria.

Urinary iodine excretion in pregnant women residing in areas with adequate iodine intake.

OBJECTIVE: Pregnancy is accompanied by profound alterations in thyroid economy and relative iodine deficiency. The aim of this study was to evaluate urinary iodine excretion of pregnant women in cities with adequate and more than adequate iodine intake. METHODS: A cross-sectional study was performed on schoolchildren and pregnant women in four cities in the Islamic Republic of Iran. Urinary iodine excretion was measured for 438 schoolchildren and 403 pregnant women. In addition, in Isfahan City, thyroid volume was measured by sonography for 30 pregnant women in each trimester of pregnancy and for 90 non-pregnant women who also had urinary iodine measurement. RESULTS: Median urinary iodine of schoolchildren was 31.2, 25.0, 20.2 and 19.3 microg/dl in Rasht, Isfahan, Ilam and Tehran, respectively. Corresponding values for pregnant women were 33.8, 21.2, 19.0 and 18.6 microg/dl. The percentage of pregnant women with urinary iodine below 20 microg/dl was 16, 45, 55 and 54, and below 10 microg/dl was 1, 7, 7 and 13, in Rasht, Isfahan, Ilam and Tehran, respectively. In Isfahan, urinary iodine was significantly decreased in the third trimester of pregnancy, compared with controls. Mean thyroid volume was 7.8 +/- 3.1 ml and 7.8 +/- 2.8 ml in pregnant and non-pregnant women, respectively. CONCLUSION: Recommended values for dietary iodine through universal salt iodisation may not be adequate for pregnant women, and the specific problem of iodine and pregnancy should be considered further in the light of the latest recommendations.