No Association Was Found Between Mild Iodine Deficiency During Pregnancy and Pregnancy Outcomes: a Follow-up Study Based on a Birth Registry

Background Severe iodine deficiency during gestation is associated with adverse pregnancy outcomes; however, the impact of mild-to-moderate iodine deficiency, though prevalent in pregnancy, remains unclear. Methods We extracted follow-up data for 7435 pregnant women from a national iodine deficiency disorders monitoring program from 2016 to 2018 and a mother–child cohort study in 2017 based on a birth registry in Shanghai. Birth outcomes were collected from the registry. Spot urine and household salt samples were collected for iodine testing. Single-factor analysis and logistic regression were used to evaluate the association between maternal iodine status and pregnancy outcomes. Results The median urine iodine level in pregnant women was 137.5 μg/L (interquartile range 82.4–211.5), suggesting mild deficiency according to WHO standards. The incidence of pregnancy termination, preterm birth, congenital malformations, low birth weight, and cesarean section was 3.2%, 4.3%, 1.4%, 2.7%, and 45.2% in the mildly iodine-deficient group and 3.4%, 4.5%, 1.4%, 2.7%, and 44.5% in the normal group, respectively. After adjusting for maternal age and education, trimesters, and preterm birth rate in the general population, the odds ratios for any outcome did not differ significantly between the two groups. Conclusion The present study suggests that mild maternal iodine deficiency is not associated with adverse pregnancy outcomes.

Content of Mineral Elements in Rat Liver Tissue with Acquired Insulin Resistance and Obesity in Combination with Iodine

The purpose of the study was to determine the content of mineral elements in the hepatocytes of rats with insulin resistance, obesity, iodine deficiency, insulin resistance in combination with iodine deficiency and obesity in combination with iodine deficiency. Materials and methods. The study was performed on 90 white nonlinear rats weighing 120-180 g, which were divided into five experimental groups: rats with insulin resistance (1st experimental group, n = 15), animals with iodine deficiency (2nd experimental group), animals with insulin resistance in combination with iodine deficiency (3rd experimental group, n = 15), obese animals (4th experimental group, n = 15), obese animals in combined with iodine deficiency (5th experimental group, n = 15). The control group consisted of 15 intact rats. The content of Fe, Ca, Cu, Mg, Zn, Mn, Cr in the liver homogenate was determined by atomic absorption spectrometry on a SPECORD M 40 spectrophotometer (Germany). Results and discussion. In animals with insulin resistance, there was a decrease in the content of copper in the liver by 26.9%, in animals with iodine deficiency the content of this trace element increased by 20.5%, and in the group of animals with insulin resistance in combination with iodine deficiency it increased by 10.1%. The iron content in the group of animals with insulin resistance is higher in relation to the control by 33.7%, in the group of animals with iodine deficiency – by 38.5%, in animals with insulin resistance in combination with iodine deficiency – by 40.8%. Regarding the content of Calcium, in the liver homogenate of animals with insulin resistance it is higher compared to the control by 24%, in animals of the second experimental group –by 26.4%, in animals of the 3rd experimental group – by 22%. The Magnesium content in animals with insulin resitance is lower compared to the control by 19%, in animals with iodine deficiency – by 25.5%, in animals with insulin resistance in combination with iodine deficiency – by 29%. As for Zinc, no significant fluctuations in the content of this trace element were detected. In animals of the 1st, 2nd and 3rd experimental groups it is lower compared to the control by 10%, 15% and 11.1%, respectively. The Manganese content in animals with insulin resistance is lower compared to the control by 13.6%, in animals with iodine deficiency – by 18.2%, in animals with insulin resistance in combination with iodine deficiency – by 14.8%. With regard to chromium, we found a probable decrease in the concentration of this trace element in animals of the group with insulin resistance by 48%, in animals of the 2nd experimental group – by 57.5%, in animals of the 3rd experimental group – by 58%. In the group of animals with obesity and obesity in combined with iodine deficiency we found an increase in copper content compared to the control by 27.4% and 36.2%, respectively. The iron content in animals with obesity exceeds the control by 34.8%, in the group of animals with obesity in combined with iodine deficiency – by 38.4%. Regarding the content of Calcium, in animals with obesity it is higher by 25.7%, and in animals with obesity in combined with iodine deficiency – by 28.4% compared to the control. Magnesium content in animals with obesity is lower by 27.3% compared to the control group, and in animals with obesity in combined with iodine deficiency – by 28.4%. Regarding Zinc, no significant fluctuations in the content of this trace element were detected. In animals of the 4th and 5th experimental groups it is lower compared to the control by 18.4% and 23.5%, respectively. The content of Manganese in the group of animals with obesity decreased by 14.8%, and in the group with obesity in combined with iodine deficiency the content of this trace element decreased by 16.2% compared to the control. With regard to chromium, we found a probable decrease in the concentration of this trace element in animals of the group with obesity by 58.1% and in the group of animals with obesity in combined with iodine deficiency by 56.2%. Conclusion. The obtained results demonstrate changes in the content of mineral elements in groups of animals with insulin resistance, iodine deficiency, insulin resistance in combination with iodine deficiency, obesity and obesity in combination with iodine deficiency

Is Dietary Iodine Intake Excessive According to the Theoretical Model of Healthy Dietary Intake Pattern in Pregnant Women and Schoolchildren: Water, Salt, or Food?

Introduction: Iodine deficiency during pregnancy can cause hypothyroidism and goiter; in schoolchildren, it can cause reduced intelligence quotient. In excess, iodine can cause thyroiditis, goiter, and Hashimoto's hypothyroidism. Currently, schoolchildren and pregnant women are classified as risk groups for excessive iodine intake and iodine deficiency, respectively. Thus, determining iodine from all sources of consumption is important for intervention planning.Objective: To construct a theoretical model for the iodine intake of schoolchildren and pregnant women of a city in the Zona da Mata Mineira region, considering a healthy diet, salt consumption and water intake.Methodology: The dietary iodine intake of pregnant women was analyzed based on a dietary iodine table compiled from an international database. A dietary plan was prepared following the Brazilian Food Guide. Iodine concentration of different salt brands sold in local establishments was checked, and drinking water samples from healthcare facilities were analyzed. A descriptive and exploratory statistical analysis was performed and the results were presented in absolute and relative frequencies, and measures of central tendency and dispersion.Results: According to the proposed diet, pregnant women and schoolchildren would have a daily intake of 71.6 μg and 71 μg, respectively. Thirteen salt brands were evaluated, 69.2% complied with the legislation and the mean iodine content was 29.88 mg. The mean concentration of iodine in water was 25 μg iodine/liter and 14 μg iodine/liter, respectively, in summer and autumn. Considering the intake of food, salt, and drinking water according to the proposed dietary plan, the daily intake for pregnant women would be 279.5 and 253.5 μg for schoolchildren.Conclusion: The daily iodine intake of schoolchildren and pregnant women according to this theoretical model was excessive, considering a healthy dietary pattern. This theoretical model can guide actions and public policies aimed at targeting all forms of iodine intake.

Iodine Deficiency and Pregnancy

Iodine deficiency is a topical health problem in many countries, including Russia. Iodine deficiency is especially adverse during intrauterine development and the first years of life. This necessitates adequate replenishment of iodine deficiency during planning and during pregnancy and breastfeeding

IODINE STATUS IN SCHOOL CHILDREN AND DISTRIBUTION OF IODINE, MERCURY, LEAD IN SOIL AND WATER IN THE ENDEMIC GOITER HILL AREA, PONOROGO

Background. Iodine deficiency disorders (IDD) remained a public health problem. Ponorogo was an IDD endemic area with prominent cases of mental retardation. Despite the lack of iodine intake, exposure to environmental heavy metals can exacerbate the effects of iodine deficiency. Objective. To describe iodine status of school children and distribution of environmental iodine and heavy metals including mercury (Hg), lead (Pb), and cadmium (Cd) in the endemic IDD hill area of Ponorogo. Method. This research is a cross-sectional study conducted in two villages in IDD endemic areas in Ponorogo, namely Dayakan and Watubonang villages, in 2011. A total of 127 urine samples of primary-school-age children were taken and analyzed for urinary iodine excretion (UIE). A total of 29 soil samples and 87 water samples were taken from the study site to measure the concentration of iodine and heavy metals Hg, Pb, and Cd. Types of water source, altitude, and land use, both soil and water source were recorded. Results. The median (min-max) UIE was 130 (14 –1187 µg/L) within the range of adequate population iodine intake according to WHO (100-199 µg/L), while the percentage of UIE <100 µg/L was still around 33.07 percent. The concentration of iodine in the soil was 33.777 mg/kg (6.640 –108.809), and the concentration of iodine in the water was 8.0 µg/L (0-49). The concentration of Hg in the soil was 68.64 ppb (7.43–562.05), and the concentration of Hg in the water was 0.00 ppb (0.00-23.24). The concentration of Pb in the soil was 3.273 ppm (0.000–25.227), while Pb was not identified in the water. The Cadmium was not detectable both in the soil and water. Conclusion. Iodine deficiency is still a public health problem in Dayakan and Watubonang villages. The environment of the endemic IDD area in Ponorogo was not completely poor in iodine, but iodine was not evenly spread and mobilized. There was a risk of environmental heavy metal exposure from Hg in the soil or water and Pb in the soil. Mercury in the environment can cause health problems due to the inhibition of the use of iodine in the thyroid gland.

The Role of Iodine for Thyroid Function in Lactating Women and Infants

Iodine is a micronutrient needed for the production of thyroid hormones, which regulate metabolism, growth, and development. Iodine deficiency or excess may alter the thyroid hormone synthesis. The potential effects on infant development depend on the degree, timing, and duration of exposure. The iodine requirement is particularly high during infancy because of elevated thyroid hormone turnover. Breastfed infants rely on iodine provided by human milk, but the iodine concentration in breast milk is determined by the maternal iodine intake. Diets in many countries cannot provide sufficient iodine, and deficiency is prevented by iodine fortification of salt. However, the coverage of iodized salt varies between countries. Epidemiological data suggest large differences in the iodine intake in lactating women, infants, and toddlers worldwide, ranging from deficient to excessive intake. In this review, we provide an overview of the current knowledge and recent advances in the understanding of iodine nutrition and its association with thyroid function in lactating women, infants, and toddlers. We discuss risk factors for iodine malnutrition and the impact of targeted intervention strategies on these vulnerable population groups. We highlight the importance of appropriate definitions of optimal iodine nutrition and the need for more data assessing the risk of mild iodine deficiency for thyroid disorders during the first 2 years in life.

Comments to clinical guidelines “Iodine deficiency disorders and diseases”

The Letter to Editor presents an analysis of some sections of the clinical guidelines «Diseases and conditions associated with iodine deficiency» published in No. 3 of the journal «Problems of Endocrinology» for 2021. In particular, the discussion deals with the coding of thyroid diseases according to ICD-10, depending on the iodine status of the population of constituent entities of the Russian Federation, as well as issues of diagnosis and treatment, such as «verification» of goiter detected by palpation, or treatment of the vast majority of children, adolescents and adults with potassium iodide. The obstacles to the epidemiological assessment of the iodine status of the population when examining schoolchildren are discussed separately, in connection with the introduction in 2020 of the new regulation, which requires the mandatory use of iodized salt for cooking in school canteens throughout the country.