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Background:Production of iodized salt in Iran for household consumption began in 1990. Previous studies have reported sustainable elimination of iodine deficiency disorders in Iran. The aim of this study was to evaluate the iodine nutritional status in Tehran in 2009.Methods:In this cross-sectional study, 383 Tehranian households were enrolled through randomized cluster sampling and a total of 639 adult subjects (242 men and 397 women), aged 19 and over, participated. A 24-hour urine sample was collected for measurement of urinary iodine, sodium, and creatinine concentrations using the digestion method, flame photometry, and autoanalyzer assay, respectively. Salt intake was estimated and iodine content of household salt was measured by titration.Results:Median (interquartile range) iodine content of household salt and urinary iodine concentration (UIC) in Tehran were 21.2 (3.2–31.7) parts per million and 70.0 (34.0–131.2) μg/L, respectively. There was no statistically significant difference in 24-hour UICs between men and women. Median (interquartile range) daily salt intake was 7.6 (5.5–9.8) g, which was not different in the two genders. According to the WHO/ICCIDD/UNICEF classification, 11.2%, 25.9%, 26.7%, 25.1%, 8.0%, and 3.2% of participants had UIC <20, 20–49, 50–99, 100–199, 200–299, and >300 μg/L, respectively.Conclusions:Mild iodine deficiency has recurred in Tehranians. The results emphasize the need for continuous monitoring in all regions, even in a country with iodine sufficiency. [ABSTRACT FROM AUTHOR]

Objective: To compare the ability of waist circumference (WC), body mass index (BMI), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) to predict cardiovascular risk factors in an urban adult population of Tehranian women.Design: Population-based cross-sectional study.Setting: Tehran, the capital of Iran.Subjects: This study was conducted on 5073 women aged 18–74 years, participants of the Tehran Lipid and Glucose Study. Demographic data were collected. Anthropometric indices were measured according to standard protocols. Cut-off points of BMI, WC, WHR and WHtR were considered as 25 kg m−2, 80 cm, 0.8 and 0.5, respectively. Blood pressure was measured and hypertension was defined based on the sixth report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. Biochemical analyses were conducted on fasting blood samples. Diabetes was defined as fasting plasma glucose ≥126 mg dl−1 or 2-hour plasma glucose ≥200 mg dl−1 and dyslipidaemia based on the third report of the National Cholesterol Education Program Expert Panel. The presence of ‘at least one risk factor’ from the three major cardiovascular risk factors (hypertension, dyslipidaemia and diabetes) was also evaluated.Results: Mean (±standard deviation) age of women was 39.9±14.6 years; mean BMI, WC, WHR and WHtR were 27.1±1.5 kg m−2, 86.5±13.5 cm and 0.83±0.08 and 0.55±0.08, respectively. Of the four anthropometric measures, WC had the highest sensitivity and specificity to identify subjects with risk factors in both the 18–39 year and the 40–74 year age categories. WC was seen to have a higher percentage of correct prediction than BMI, WHR and WHtR.Conclusion: It is concluded that WC is the best screening measure for cardiovascular risk factors, compared with BMI, WHR and WHtR, in Tehranian adult women. [ABSTRACT FROM AUTHOR]

Background: Northern rural areas of Tehran have been shown to have severe iodine deficiency in our previous studies. In 1989 the inhabitants of these villages received an injection of iodised oil, followed by iodised salt distribution in 1993. The aim of the present study was to evaluate the effect of the iodine supplementation on iodine-deficient schoolchildren with hypothyroidism in these villages. Methods: In total, 571 students aged 6-14 years were studied. Goitre was graded according to the World Health Organization classification. Serum concentrations of thyroid hormones (thyroxine (T4) and triiodothyronine (T3)) and thyroid-stimulating hormone (TSH) were determined using commercial kits, and urinary iodine was measured using a digestion method. The results were compared with data from our previous study in 1989. Results: Total goitre rate decreased by 42% in 1999 compared with that in 1989. A significant decrease in Grade 2 goitre concomitant with an increase in Grade 1 goitre was seen (P<0.001). Values of the variables studied before (1989) and 10 years after iodine supplementation (1999) were: median urinary iodine excretion, 2.0 vs. 19.0 μg dl-1 (P<0.001); T4, 6.5±2.0 vs. 8.4±1.6 μg dl-1 (P<0.001); T3, 177±38.0 vs. 145±29.0 ng dl-1 (P<0.001); TSH, 10.8±15.1 vs. 1.8±0.8 μU ml-1 (P<0.001). No correlation was found between thyroid hormones and TSH on the one hand, and goitre and urinary iodine, on the other. Serum T4, T3 and TSH concentrations were within normal ranges in all schoolchildren in 1999. Conclusion: This study showed that euthyroidism induced by administration of iodised oil in iodine-deficient schoolchildren with hypothyroidism is sustained following the consumption of iodised salt. [ABSTRACT FROM AUTHOR]

Background: Accurate assessment of thyroid status during pregnancy is vital for maternal and fetal health. Because free thyroxine (FT4) values in pregnancy vary widely between methods, assessment of total T4 (TT4) and FT4 index (FT4I) may be superior to FT4 in pregnant women. However, trimester-specific reference intervals for FT4I have not yet been established. In this longitudinal self-sequential survey, we aimed at determining the trimester-specific reference range for FT4I in healthy Iranian women with singleton pregnancies., Methods: A total of 466 healthy pregnant women were evaluated. After exclusion of women with history, ultrasonographic, or laboratory evidence of any thyroid disorder or iodine deficiency and those who were positive for thyroid autoantibodies, 152 women entered the study. Serum thyrotropin (TSH), TT4, and triiodothyronine-resine uptake were measured by an immunoassay method. Reference intervals were defined as 5th and 95th percentiles, using the bootstrap-based procedure., Results: Mean values in the first, second, and third trimesters were 1.7±1.5, 1.9±1.8, and 1.9±1.8 mIU/L for TSH; 12.9±3, 14.4±3.1, and 13.6±3.3 μg/dL for TT4; and 12.8±3.5, 14.2±3.3, and 13.5±3.8 for FT4I, respectively. Reference intervals in the first, second, and third trimesters were as follows (respectively): TSH-0.2-3.9, 0.5-4.1, and 0.6-4.1 mIU/L; TT4-8.2-18.5, 10.1-20.6, and 9-19.4 μg/dL; and FT4I-8.5-19, 9.7-21, and 8.7-20.4. Serum TSH had no significant correlation with TT4. Serum TSH had a significant but weak correlation with FT4I only in the first trimester (r=-0.24, p=0.006)., Conclusion: This study, for the first time, establishes the trimester-specific reference intervals for FT4I in a reference population of normal iodine-sufficient pregnant Iranian women.