Iodine deficiency during the first two years of life may cause irreversible brain damage and mental retardation. The aim of the present study was to investigate, for the first time, the effect of iodine fortified milk on the iodine status of lactating mothers and their infants. In this multicenter randomized controlled trial, 84 lactating mother-infant pairs from health care centers were randomly selected. After meeting the inclusion criteria, lactating mothers were randomly assigned to two groups: the iodine fortified milk group and the control group (n = 42 each). Maternal and infant urine and breast milk samples were collected at 3–5 (baseline), 7, 10, 14 days, and 1 month postpartum, for a measurement of the iodine concentration. A total of 84 lactating mothers, with a mean age of 28.2 ± 4.5 years, and 84 infants, with a mean age of 4.2 ± 0.7 days, were included in the study. Compared to mothers of the control group, mothers receiving iodine fortified milk had higher urinary (p < 0.001) and breast milk (p < 0.001) iodine concentrations. Urinary iodine levels in infants revealed no significant differences between the two groups. The findings of this study indicate that supplementation with daily iodine fortified milk provides iodine nutrition adequacy among lactating mothers. However, it had no effect on the iodine status of infants, who were previously iodine sufficient.

Background Iodine deficiency and related disorders were very common in Iran prior to 1996, when universal salt iodization (USI) was implemented and in 2000 Iran was declared iodine deficiency disorders (IDD) free. The aim of this study was to evaluate the adequacy of iodine intake by Iranian households in all 30 provinces of Iran, a quarter of a century after the intervention. Methods A total of 18,000 school-aged children (8–10 years with mean 8.7 ± 1 year) were included in this study. Urine samples were collected from all children for measurement of urinary iodine excretion and 1800, 210 and 3000 salt samples were randomly collected from the family kitchen, production site of 73 salt factories and distribution circles of 30 provinces, respectively. Results The median urinary iodine concentration (UIC) of participants was 161 μg/L. The proportion of children with UIC of, 20–49, 50–99 and ≥ 100 μg/L were 10.3, 15.9 and 73.7%, respectively. The mean (± SD) and median salt iodine values were 28.2 (± 12.6) and 31.7 ppm, at the production site, and 31.5 (± 13.6) and 29.6 ppm at the distribution circles, respectively. About 80% of factory salts had more than 20 ppm iodine. 98% of households consumed iodized salt, 80% had appropriate salt storage, and 83% of the household salts contained ≥ 20 ppm. Conclusions Based on the results of this study, Iranian populations are consuming adequate iodine. The well-maintained and monitored USI program has improved the dietary iodine intakes of the population, and the country has achieved all criteria of a well-controlled IDD program.

Back ground: Iodine deficiency is one of the important factors in increasing the recall rate in congenital hypothyroidism (CH) screening programs. The present study assessed whether the iodine status of the general population may predict the recall rate or vice versa. Methods: In the current national study, among 1,382,229 live births delivered between March 2010 and March 2011, 1,288,237 neonates were screened for detecting CH by TSH (thyroid stimulating hormone) measurement via heel prick sampling. Simultaneously, a total of 11,280 school-aged children, aged 7–8 years, were selected using random multi-cluster sampling for measurement of urinary iodine. Results: A negative correlation was found between median urinary iodine (MUI) and the recall rate (r = −0.33, p = 0.03). No correlation was found between MUIC (median urinary iodine concentration) and the incidence rate of CH. Linear regression analysis showed a 0.1% increase in the recall rate for a one unit decrease in MUIC (β = −0.11, 95% CI: −0.2, −0.1, p = 0.03). MUIC, at a cut-off point of 144.7 µg/L, was predictive for a recall rate < 3% (p = 0.05). Conclusion: Frequencies of TSH ≥ 5 mU/L may be a more sensitive indicator for iodine status during pregnancy rather than in the general population. As higher recall rates reflect inadequate iodine nutrition, sufficient iodine supplementation is needed to reduce the recall rate in such communities.