Iodine Deficiency, Implications for Mental and Psychomotor Development in Children1

Iodide is an essential micronutrient present in very small quantities in the human body, with a fundamental action for the adequate synthesis of thyroid hormones, which are critical for cell differentiation, growth and metabolism. In the form of iodide, iodine is widely distributed in the environment, although in an irregular manner, occurring in abundant amounts in the oceans and in coastal areas and scarcely found on islands and mountains. The diet is the main source of iodine, whose intake varies according to the amount present in soil and water and according to eating habits. Governmental policies have been adopted to satisfy and guarantee the necessary daily supply of iodine, such as fortification of industrialized salt for domestic iodine consumption or addition to the bread commonly consumed in a given region, or the offer of iodized oil to the population, or even iodine supplementation through medications. Iodide deficiency is the main avoidable cause of brain damage to fetuses and children, as well as retardation of psychomotor development. Thyroid hormones are almost universally involved in the development and proliferation of fetal neural tissue. Permanent lesions of the cerebral cortex, hippocampus and cerebellum may occur, with loss of, or damage to the brainstem or spinal cord, affecting cortical areas that integrate highly specialized stimuli, which become poorly defined on an anatomical basis, including silent areas of the associative cortex. One of the more significant metabolic problems due to dietary iodine deficiency is the presence of goiter (increased volume of the thyroid gland). Thyroid carcinoma is the most frequent endocrine neoplasia affecting the human species and plasma iodine concentration is related to the development of specific subtypes of this neoplasia. An increased prevalence of follicular carcinoma, a more aggressive tumor, has been observed in areas of iodine deficiency, while the correction of this deficiency is associated with a higher prevalence of papilliferous carcinoma, a less aggressive form. CONCLUSION: An ideal plasma iodide concentration is necessary to insure the proper mental development of fetuses and young children and to minimize the aggressiveness of thyroid cancer from follicular cells in humans.

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Thyroid Hormones and the Psychomotor Development of the Newborn

European Psychiatry ◽

10.1016/s0924-9338(09)70390-6 ◽

2009 ◽

Vol 24 (S1) ◽

pp. 1-1

Author(s):

S. Ares ◽

J. Quero ◽

G. Morreale de Escobar

Keyword(s):

Thyroid Hormones ◽

Brain Development ◽

Iodine Deficiency ◽

Psychomotor Development ◽

Postnatal Life ◽

Fetal Life ◽

Developmental Phase ◽

Increased Risk ◽

Early Postnatal Life ◽

Iodine Deficiency In Pregnancy

Iodine is a trace element which is essential for the synthesis of thyroid hormones. If maternal iodine deficiency in pregnancy is severe, fetal brain damage will occur. This damage is irreversible after birth. Mild/moderate iodine deficiency during pregnancy and early postnatal life is associated with neuro/psycho-intellectual deficits in infants and children. The severity is not only related to the degree of iodine deficiency, but also to the developmental phase during which it is suffered, the most severe being the consequence of iodine deficiency during the first two trimesters of pregnancy. The close involvement between human brain development and thyroid hormones is widely accepted. The effects of T3 on the central nervous system are mediated by the regulation of the expression of genes that synthesize proteins implicated in cerebral neurogenesis, neuronal migration and differentiation, axonal outgrowth, dendritic ontogeny, and synaptogenesis. They are also necessary for cerebellar neurogenesis (predominantly during early postnatal life), gliogenesis (predominantly during late fetal life to 6 months postnatally), and myelogenesis (during the second trimester of gestation to 2 years of postnatal life). From clinical studies on the effect of iodine deficiency of both mother and fetus it becomes clear that T4 is required for brain development during gestation.Low T4 levels during neonatal life could be a negative factor contributing to the neurodevelopmental problems of very preterm infants. Indeed, retrospective studies have shown a relationship between hypothyroxinemia and developmental delay and an increased risk of disabling cerebral palsy.

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Impairment of neuromotor and cognitive development in iodine-deficient schoolchildren with normal physical growth

Acta Endocrinologica ◽

10.1530/acta.0.1290501 ◽

1993 ◽

Vol 129 (6) ◽

pp. 501-504 ◽

Cited By ~ 35

Author(s):

F Azizi ◽

A Sarshar ◽

M Nafarabadi ◽

A Ghazi ◽

M Kimiagar ◽

...

Keyword(s):

Cognitive Development ◽

Children And Adolescents ◽

Thyroid Function ◽

Iodine Deficiency ◽

Endemic Goiter ◽

Physical Growth ◽

Psychomotor Development ◽

Somatic Development ◽

Intellectual Quotient ◽

The Mean

In order to detect somatic and psychomotor disturbances in children and adolescents residing in areas of iodine deficiency, schoolchildren from three areas with different degrees of iodine deficiency were studied. In Randan, the prevalence of severe endemic goiter was accompanied by alteration in thyroid function, increased thyrotropin levels and retardation of both bone and psychomotor age and decreased intellectual quotient. In Tehran, where iodine deficiency is mild, visible goiter was present in 1 5% of schoolchildren but no alterations in thyroid function, serum thyrotropin, somatic or psychomotor development could be detected. In Zagoon, where the prevalence and severity of goiter was less than Randan but more than Tehran, thyroid function was normal but slightly decreased as compared to Tehran; somatic development was unaltered, but retardation in psychomotor development was evident and the mean intellectual quotient was less than that of Tehranian schoolchildren. These findings indicate the occurrence of physical and psychomotor disturbances in apparently normal schoolchildren from areas of iodine deficiency. Alteration in psychomotor development may occur in children with normal physical growth, due to iodine deficiency.

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Iodine deficiency and its consequences for cognitive and psychomotor development of children

Italian Journal of Pediatrics ◽

10.1186/1824-7288-40-s1-a15 ◽

2014 ◽

Vol 40 (S1) ◽

Cited By ~ 2

Author(s):

Roberto Gastaldi ◽

Monica Muraca ◽

Agnese Beltramo ◽

Elena Poggi

Keyword(s):

Iodine Deficiency ◽

Psychomotor Development

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Impact of iodine supplementation during preconception, pregnancy and lactation on maternal thyroid homeostasis and offspring psychomotor development: protocol of the IodineMinho prospective study

BMC Pregnancy and Childbirth ◽

10.1186/s12884-020-03376-y ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Maria Lopes-Pereira ◽

Susana Roque ◽

Patrício Costa ◽

Anna Quialheiro ◽

Nadine Correia Santos ◽

...

Keyword(s):

Pregnant Women ◽

Iodine Deficiency ◽

Energy Content ◽

Thyroid Volume ◽

Endocrine Function ◽

Psychomotor Development ◽

Childbearing Age ◽

Iodine Supplementation ◽

Pregnancy And Lactation ◽

Maternal Thyroid

Abstract Background Iodine deficiency is the most common cause of preventable brain harm and cognitive impairment in children. Portuguese women of childbearing age, pregnant women and their progeny were shown to have inadequate iodine intake. Consequently, the Portuguese Health Authorities have recommended a daily supplementation with 150–200 µg iodine in preconception, pregnancy, and lactation. The IodineMinho study intends to evaluate whether (i) this recommendation impacted on the prevalence of iodine deficiency in pregnant women from the Minho region of Portugal, (ii) the time of initiation of iodine supplementation (if any) influences the serum levels of thyroid hormones at several intervals during pregnancy and (iii) there are serum thyroid-hormone parameters in the 1st trimester of pregnancy that predict psychomotor development of the child at 18 months of age. Methods Most Portuguese women are followed throughout pregnancy in community Family Health Units, where family physicians may choose to follow the National recommendation or other, concerning iodine sufficiency. This study will recruit women (N = 304) who intend to become pregnant or are already pregnant from 10 representative Units. Physician’s approach and prescriptions, sociodemographic, nutrition and clinical information will be obtained at baseline and throughout pregnancy. To evaluate endocrine function, blood and urine samples will be collected at recruitment, once in each trimester of pregnancy, at delivery and 3 months after delivery. Breastmilk samples will be collected for iodine and energy content analysis. Children will be evaluated for psychomotor development at 18 months. Maternal thyroid volume will be evaluated by ultrasound scan at baseline, in the 3rd trimester and at 3 months after delivery. Discussion Iodine deficiency early during development precludes children from achieving full intellectual capabilities. This protocol describes a study that is innovative and unique in its detailed and comprehensive evaluation of maternal and child endocrine and psychomotor parameters. By evaluating the effectiveness of the iodine supplementation recommendation, it will contribute to the public health systems’ efforts to provide excellence in maternal and infant care. Trial registration ClinicalTrials.gov, NCT04288531. Registered 28 February 2020-Retrospectively registered.

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Iodine deficiency disorders as a non-infectious epidemic: a look at the problem at the tome of COVID-19 pandemic

Terapevticheskii arkhiv ◽

10.26442/00403660.2020.10.000768 ◽

2020 ◽

Vol 92 (10) ◽

pp. 4-8

Author(s):

G. A. Mel’nichenko ◽

E. A. Troshina ◽

G. A. Gerasimov

Keyword(s):

Thyroid Cancer ◽

Power Plant ◽

Nuclear Power Plant ◽

Iodine Deficiency ◽

Nuclear Power ◽

Power Plants ◽

Radioactive Iodine ◽

Iodine Intake ◽

Psychomotor Development ◽

Salt Iodization

Radioactive iodine, flying out of the destroyed reactor of the Chernobyl nuclear power plant, like a corona virus quickly spread throughout Europe. Iodine deficiency in the regions of Ukraine, Belarus and Russia adjacent to nuclear power plants became a factor in increased uptake of radioactive iodine by the thyroid gland in children and after 5 years led to an epidemic of thyroid cancer. Optimal iodine intake could become a kind of vaccination, which sharply reduces the risk of developing thyroid cancer, as has happened after the accident at the Fukushima nuclear power plant in Japan. Endemic goiter was eliminated 50 years ago, but returned to the country in the early 1990s after the collapse of iodized salt production and has not been eliminated to this day due to the lack of a legislative framework for mandatory salt iodization. The actual average consumption of iodine by residents of Russia is from 40 to 80 mcg per day, which is 23 times less than the recommended norm. Mild and moderate iodine deficiency was detected throughout the Russian Federation, and it is more typical for the the rural population. The iodine deficiency has the greatest negative effect on the psychomotor development of the child during the critical period the first 1000 days of life from the moment of conception to the end of the second year of life. According to WHO, over the past 20 years, iodine deficiency has been eliminated in 115 countries of the world, and the number of iodine-deficient countries has dropped to 25, but Russia is still among them. We believe that after the COVID-19 pandemic, it will no longer be necessary to prove the need for effective support for the prevention of both infectious and non-infectious diseases, and the declared preventive direction of Russian medicine will indeed become such.

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