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The effects of iodine on intelligence in children: A meta-analysis of studies conducted in China
Abstract
This study quantifies the effects of iodine on the intellectual development of children using a systematic manual literature search of Chinese publications related to iodine deficiency disorders. The Chinese Medical Reference Database, Medline, and Cochrane library were searched electronically in Chinese and English. Inclusion criteria included: studies conducted in China, comparing children (<16 ys) living in naturally iodine sufficient (IS) with those in severely iodine deficient (ID) areas, or children in ID areas born before and after the introduction of iodine supplementation. Intelligent Quotient (IQ) was measured using Binet or Raven Scales. The iodine sufficient control groups were comparable socially, economically, and educationally with the study groups. Random effects models were used in the meta-analysis. Effect size was the standard deviation IQ point (SIQP), which is equivalent to 15 IQ. Thirty-seven reported studies, total 12,291 children, were analysed. The effect size was an increase of 0.83, 0.82, and 0.32 SIQP respectively, for the children living in IS communities compared with those living in ID areas with no iodine supplementation, with inadequate iodine supplementation, or children who had received iodine during their mothers' pregnancy and after birth. These equal to 12.45, 12.3, 4.8 IQ points. Compared with that of children whose mothers were persistently exposed to ID, the total effect size of the 21 entries was an increase of 0.58 SIQP (8.7 IQ points) in the group receiving iodine supplementation during pregnancy. Furthermore, there was an increase on 1.15 SIQP of Binet or 0.8 SIQP on Raven Scale (17.25 or 12 IQ points) for children born more than 3.5 years after iodine supplementation program was introduced. The level of iodine nutrition plays a crucial role in the intellectual development of children. The intelligence damage of children exposed to severe ID was profound, demonstrated by 12.45 IQ points loss and they recovered 8.7 IQ points with iodine supplementation or IS before and during pregnancy. Iodine supplementation before and during pregnancy to women living in severe ID areas could prevent their children from intelligence deficit. This effect becomes evident in children born 3.5 years after the iodine supplementation program was introduced.
... In the GBD study, developmental and intellectual disabilities refer to situations where an individual's intellectual abilities are below the average. The severity of intellectual disabilities is categorized into five levels based on IQ test scores (standardized with a mean of 100), including borderline (IQ scores of 70-85), mild (IQ scores of 50-69), moderate (IQ scores of [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49], severe (IQ scores of 20-34), and profound (IQ scores of 0-19) (24). The nonfatal iodine deficiency burden includes estimates for visible goiter (grade 2) and its associated consequences such as thyroid dysfunction, heart failure, and intellectual disability but excludes estimates for subclinical iodine deficiency or nonvisible goiter (grade 1) caused by iodine deficiency (25). ...
... This could be due to the increased demand for iodine during adolescence, and its decreased content derived from food and salt (46). Even a mild iodine deficiency during pregnancy can result in a lowered IQ and inferior academic performance in primary school when compared to peers (47,48). Adolescents should ensure that they consume enough iodine every day. ...
Objective
The objective of this study was to assess the global burden of disease for developmental and intellectual disabilities caused by iodine deficiency from 1990 to 2019.
Methods
Using data from the global burden of disease (GBD) 2019, we conducted a cross-country inequity analysis to examine the worldwide burden of developmental and intellectual disabilities caused by the issue of iodine deficiency from 1990 to 2019. Absolute and relative inequality were assessed by the slope index of inequality and the concentration index, respectively. After summarising the latest evidence, we also projected the age-standardized prevalence and years lived with disability (YLD) rates up to 2030 using the BAPC and INLA packages in R statistical software.
Results
In 2019, the global age-standardized prevalence and YLD rates for developmental and intellectual disabilities due to iodine deficiency were 22.54 per 100,000 population (95% UI 14.47 to 29.23) and 4.12 per 100,000 population (95% UI 2.25 to 6.4), respectively. From 1990 to 2019, the age-standardized prevalence and YLD rates of developmental and intellectual disabilities due to iodine deficiency decreased significantly. Geographic distribution showed that areas with lower socio-demographic indices (SDI) were the most affected. The correlation between higher SDI and lower prevalence highlights the role of economic and social factors in the prevalence of the disease. Cross-national inequity analysis shows that disparities persist despite improvements in health inequalities. In addition, projections suggest that the disease burden may decline until 2030.
Conclusion
This research underscores the necessity for targeted interventions, such as enhancing iodine supplementation and nutritional education, especially in areas with lower SDI. We aim to provide a foundation for policymakers further to research effective preventative and potential alternative treatment strategies.
... The overall mean FI score was 110 (14.0) points on the CFT scales. The mean UIE was 59 (27) μg/24 h and 100 (53) μg/24 h for the younger (CFT-1) and older (CFT-20R) participants, respectively. The majority (66%) of the participants had a UIE above the EAR, and 1 Data are shown as mean (± SD) or n (%) 2 Exclusive breastfeeding duration (weeks) was defined as the number of weeks of both exclusive (breast milk only with no other food or drink) and predominant (breast milk in combination with water or waterbased drinks) breastfeeding 3 4) weeks, and the majority of the participants' fathers had a high education level (73% and 76%). ...
... The authors observed that children exposed to severe iodine deficiency displayed a 12.5-point lower IQ. Moreover, compared with children whose mothers were persistently exposed to iodine deficiency, children receiving iodine supplementation had 8.7 points higher IQ than those receiving iodine supplementation during pregnancy [27]. While most of the aforementioned studies have investigated the effect of iodine deficiency on the critical phases of brain development, i.e. in the uterus and during the first life years, this study shows the importance of adequate iodine intake beyond this time frame. ...
Purpose
Iodine deficiency increases the risk of cognitive impairment and delayed physical development in children. It is also associated with cognitive impairment in adults. Cognitive abilities are among the most inheritable behavioural traits. However, little is known about the consequences of insufficient postnatal iodine intake and whether the individual genetic disposition modifies the association between iodine intake and fluid intelligence in children and young adults.
Methods
The cultural fair intelligence test was used to assess fluid intelligence in the participants of the DONALD study (n = 238; mean age, 16.5 [SD = 7.7] years). Urinary iodine excretion, a surrogate iodine intake marker, was measured in 24-h urine. Individual genetic disposition (n = 162) was assessed using a polygenic score, associated with general cognitive function. Linear regression analyses were conducted to determine whether Urinary iodine excretion was associated with fluid intelligence and whether this association was modified by individual genetic disposition.
Results
Urinary iodine excretion above the age-specific estimated average requirement was associated with a five-point higher fluid intelligence score than that below the estimated average requirement (P = 0.02). The polygenic score was positively associated with the fluid intelligence score (β = 2.3; P = 0.03). Participants with a higher polygenic score had a higher fluid intelligence score.
Conclusion
Urinary iodine excretion above the estimated average requirement in childhood and adolescence is beneficial for fluid intelligence. In adults, fluid intelligence was positively associated with a polygenic score for general cognitive function. No evidence showed that the individual genetic disposition modifies the association between Urinary iodine excretion and fluid intelligence.
... 22,24,41 In contrast, optimum brain development in ID environments is often considered insufficient, therefore it is imperative that during pregnancy the mother's iodine intake stays repleted by iodine rich foods such as seafood (fish), bread and dairy products. 8,22,24 43 noted that children exposed to severe ID were liable to a 12.45 IQ points loss compared to those in iodine sufficient areas (UIC >100 µg/g iodine-to-creatine ratio). 41 The meta-analysis also suggested that the use iodine supplementation or USI prior to and during pregnancy could result in a 8.7 IQ point recovery. ...
... 5 In contrast, the study observed a loss of IQ points (1.4-3.8) instead of a gain 41,43 , in mothers who received levothyroxine therapy during pregnancy for subclinical hypothyroidism. 44 Evidently, the status of the thyroid in terms of normal physiological function and adequate iodine supply during pregnancy is critical in neurodevelopment, yet the use of prophylaxis may not provide the desired outcomes. ...
During pregnancy, an increase in dietary iodine intake arises due to physiologic adaptation, a phenomenon that is characterised by complex effects that increase metabolic demands and incite hormonal changes. The presence of iodine deficiency (ID) during critical stages of gestation is associated with neurodevelopmental deficits and poses as a risk factor to the development of postpartum depression that can disrupt early mother-infant interaction. A pertinent question is at what stage of pregnancy should pregnant women be advised to take iodine-containing supplements. The narrative review aims to evaluate the recommended level of iodine supply of childbearing age, pregnant and lactating women in relation to foetal brain development and pursues to demonstrate the nutraceutical properties of seaweed as a complimentary supplement for maintaining iodine sufficiency. To achieve this, PICO was used for synthesising foreground research questions, and this was followed up by an electronic search of published data in Embase. As part of the search strategy the exclusion and inclusion criteria for eligible articles took place in Embase. To increase the variation in resources PubMed, Google Scholar, Annual Reviews and Semanticscholar were utilised. Results indicate that the dietary iodine recommendations for pregnant and lactating women are ambiguous, as they fluctuate between 150-300 μg/d and interestingly, the reference urinary iodine concentration (UIC) value of 150 µg/L is not based on direct experimental evidence; this amount is simply the best estimate for ensuring optimal iodine intake. Further observations revealed that children exposed to severe ID are liable to a 12.45 IQ points loss using the Binet or Raven Scales compared to those in iodine sufficient areas (UIC >100 µg/g UI/Cr), were the use of iodine supplementation prior to and during pregnancy could result in an 8.7 IQ point recovery. Relatedly, seaweed supplementation markedly increased urinary iodine excretion from ~266µg/d (SD:155.8) in the control group to ~567µg/d (SD:177.8, p<0.01) post consumption. Importantly these results confirm the bioavailability of iodine in seaweed. Notably, cytoarchitectural development is not exclusive to in utero and exposure to postpartum ID is associated with behavioural disorders (ADHD), learning difficulties and subtle decrements in working memory and auditory processing speed. Overall, a glut of complexities governing ID, emerging themes (dietary trends, metabolic syndrome, psycho-nutrition) and brief encounters (seaweed toxicity, processing and cooking methods) are discussed. In closing, a possible long-term indicator of iodine status is evaluated alongside the novel use of iodised food biofortification to tackle emerging micronutrient deficiencies.
... Many studies have compared school children living in IDD endemic and non-endemic areas. The results show that children living in endemic areas have more inadequate cognitive development levels and school achievement (Grantham-McGregor et al., 1999;Tee et al., 1999;Huda et al., 1999;Qian, et al. ., 2005). The metaanalysis results of 18 studies involving 2,214 subjects showed that the mean IQ and psychomotor scores in subjects who experienced IDD were 13.5 points lower than subjects from the non-IDD population (Bleichrodt and Born, 1993). ...
... The trend distribution of children's IQ curves in endemic areas shows a leftward trend, with a mean IQ deficit of 11 points in populations in IDD endemic areas. This result was confirmed by a meta-analysis of 36 recent studies conducted in China (Qian, et al., 2005) and a meta-analysis of previous studies. Therefore, in endemic goiter areas there is a higher prevalence of learning difficulties in school children (Bleichrodt and Born, 1993). ...
... Results from a meta-analysis of data showed that, on an average, intelligence quotient (IQ) score of 12.5 points were lesser in iodine deficient children than the iodine sufficient children [39]. ...
... World Health organization (WHO) recommends use of iodized salt is the mainstay therapy in treating iodine deficiencies and supplementation only in prone groups from severely deficient regions where salt iodization is not achievable. Suggested dosages for daily iodine intake indicates higher requirements for pregnant and lactating women as compared to non-pregnant women of child bearing age [39]. (Table 2 near ...
The iodine intake in a pregnant woman has been closely correlated with development of transient congenital hypothyroidism which leads to decline in neurocognitive abilities of the child later in life as the effects are very subtle at birth. Both low and excess ingestion of iodine has been found to contribute to this cause, although iodine deficiency is more commonly observed in women of underdeveloped nations. It poses risks not only to the foetus but also to the mother leading to obstetric complications such as still birth and spontaneous abortions. It can be prevented using WHO recommended daily iodine supplementation in deficient regions or decreasing the excess load in groups exposed to high iodine. Programmes designed to screen the new-born at birth can also help in improving the quality of life of the child. The deficient iodine condition is managed by administration of levothyroxine in dosage range of 10-15 mcg/kg/day. Generally, the prognosis of infants starting treatment early in life have a better neurocognitive outcome as compared to the treated infants late age at a later age. Avoidance of agents causing iodine exposure has resulted in decrease in the abnormal thyroid function levels.
... Iodine deficiency during pregnancy has been reported to be associated with increased risks of congenital hypothyroidism, neonatal hypothyroidism and neuropsychomotor retardation (Toloza et al., 2020). In a meta-analysis with 37 studies of 12,291 Chinese children, children exposed to iodine deficiency (with a median urinary iodine concentration (UIC) of < 100 µg/L) were demonstrated to have 12.5 IQ points lower than children living in iodine sufficient regions (with a median UIC of ≥ 100 µg/L) (Qian et al., 2005). ...
The median urinary iodine concentration (UIC) of school-aged children has been commonly used as a surrogate to assess iodine status of a population including pregnant women. However, pregnant women have higher iodine requirements than children due to increased production of thyroid hormones. The aim of the study was to evaluate the iodine status of pregnant women and children as well as their household salt iodine concentration (SIC) in Quzhou, Zhejiang Province, China. Eligible pregnant women and children from all six counties of Quzhou in 2021 were recruited into the study. They were asked to complete a socio-demographic questionnaire and provide both a spot urine and a household table salt sample for the determination of UIC and SIC. A total of 629 pregnant women (mean age and gestation weeks of 29.6 years and 21.6 weeks, respectively) and 1273 school-aged children (mean age of 9 years and 49.8% of them were females) were included in the study. The overall median UIC of pregnant women and children in our sample was 127 (82, 193) μg/L and 222 (147, 327) μg/L, respectively, indicating sufficient iodine status in children but a risk of mild-to-moderate iodine deficiency in pregnant women. Distribution of iodine nutrition in children varied significantly according to their sex and age (P < 0.05). The rate of adequately household iodised salt samples (18–33 mg/kg) provided by pregnant women and children was 92.4% and 90.6%, respectively. In conclusion, our results indicated a risk of insufficient iodine status in pregnant population of China, but iodine sufficiency in school-aged children. Our data also suggested that median UIC of children may not be used as a surrogate to assess iodine status in pregnant women.
... 3,4 A 2005 meta-analysis of Chinese studies comparing intelligence quotient (IQ) of children living in naturally iodine-sufficient areas to children living in severely iodine deficient areas found that the IQ of iodine-sufficient children, on average, was 12.45 points higher. 5 In spite of universal iodination program from 1993, urinary iodine is still low. The results of survey conducted by UNICEF and ICCIDD in Bangladesh during 1993 (70.2%), 1999 (45.6%) and 2005 (38.6%) show iodine deficiency that presented still alarming picture of iodine deficiency in the country especially in pregnancy. ...
Dinajpur Med Col J 2015 Jul; 8 (2):144-151] Iodine deficiency disorders (IDD) are global public health problem. All groups of people are affected by it, but growing children and pregnant women are most vulnerable. This study was aimed to determine the urinary iodine status of clinically euthyroid pregnant women during different trimesters of pregnancy. This cross sectional observational study comprised of 114 pregnant women in different trimesters and 38 healthy controls. Each trimester included 38 subjects. The urinary iodine content was estimated in spot urine sample using the method of Dunn et al. with the modification of Sandell & Kolthoff (wet digestion method). Most of the pregnant women belonged to occupation as house wife (68.4%) whereas most of the controls were service holder (94.7%). Cent percent studied subjects were taking packet salt. Median value of urinary iodine in pregnant women was 40.65 g/L compared to 37.30 g/L in control group. Mean (±SEM) urinary iodine was not statistically different between pregnant and non-pregnant women (50.07±4.65 vs. 54.87±8.80; p = 0.615). Considering the WHO recommended cutoff value (<150 g/L), cent percent of pregnant women in 1 st and 3 rd trimesters and about 90% in 2 nd trimester were deficient for iodine nutrition. Even when cutoff value considered at 100 g/L, again cent percent of 1 st trimester women whereas around 80-85% of 2 nd and 3 rd trimester women found deficient for iodine nutrition. Among all the subjects more than 60% were moderately (<50 g/L) deficient while about 25% were severely (<20 g/L) deficient for iodine nutrition. There was no statistical difference for UI among the trimesters neither in the goitrous group (p = 0.224) nor in the non-goitrous group (p = 0.171). UI level did not correlate with nor seemed predictable by any of variables as: age of mother, socioeconomic status, gravida, gestational weeks or presence of goiter. This study demonstrated that UIC during pregnancy as well as in non-pregnant women is markedly lower than those previously reported in our country. Further studies are needed to elucidate the cause and find out ways to correct the problem.
... Our finding correlates with Hollowell JG and his colleagues [20], and find that majority (46.2%) of our overt hypothyroidism patients were from West Sudan and showed a significant association between race and overt hypothyroidism. This finding clearly explain that West of Sudan are iodine deficient area, which consider to be risk factor for hypothyroidism this is supported by the finding of a randomized trial and several population-based studies of women living in severely iodine deficient regions, iodine supplementation to women prior to conception or during early pregnancy was associated with substantially better neurologic and developmental outcomes in children [21,22] The current study showed significant association between hypothyroidism and history of infertility, history of miscarriage, stillbirth. Our result was similar to Allan et al., who demonstrated an increased risk of fetal loss and miscarriage in patients with hypothyroidism [23]. ...
Background: Thyroid disorders constitute one of the most common endocrine disorders seen in pregnancy. Hypothyroidism has been linked with poor reproductive health and pregnancy outcomes.Objectives: To estimate the rate of hypothyroidism in a sample of Sudanese
women during early pregnancy and to ascertain pattern and risk factors for
hypothyroidism during pregnancy.
Methodology: It was descriptive cross-sectional and hospital-based
study carried out at Omdurman Maternity Teaching Hospital, Khartoum State
Sudan during the period March-November, 2017. Four hundred and ten (410)
participants of pregnant women in first trimester of pregnancy <13 weeks of
gestation, singleton pregnancy were incorporated. Data was collected by
structure questionnaire. Laboratory testing of a blood sample for thyroid function
was done. Demographic and clinical data concerning personal and family
history (in first - and second-degree relatives) of thyroid disorders and/or other
autoimmune diseases such as types1diabetes were recorded.
Results: Four -hundred-and-ten women were included, the age distribution
ranged from 18 to 46 years with a mean (standard deviation) age of 28.65
years. The average ranges of TSH was (0.5-6.5 mIU/L) and T4 (10.5 - 20.4
Pmol/L) and there was slight fluctuation of the mean values of thyroid hormones
according to trimester in euthyroid pregnant women. Subclinical and overt
hypothyroidism was found in 56 (13.7%) of women. Forty-three women (10.5%)
had subclinical hypothyroidism, thirteen (3.2%) had overt hypothyroidism. The
current study showed significant association between overt hypothyroidism and
history of infertility, history of miscarriage, stillbirth, preterm deliveries, BMI and
iodine deficiency at (P. value<0.05).
Conclusion: Our study demonstrated a high prevalence of hypothyroidism
among Sudanese pregnant women. Universal screening of pregnant women for
thyroid dysfunction should thus be adopted throughout Sudan.
Keywords: Hypothyroidism; Pregnancy; Screening
... Mild-to-moderate iodine deficiency during pregnancy has also been shown to adversely affect thyroid hormones [42], and observational studies have suggested that mild-to-moderate maternal iodine deficiency can have adverse effects on neurodevelopment in children [43,44]. A meta-analyses of Chinese studies suggested that children living in areas with iodine deficiency have a reduction of IQ of around 12 points compared iodine-sufficient children [45]. However, it is difficult to tease out the direct effect of iodine deficiency during infancy on neurological development. ...
Purpose of Review
Iodine deficiency is a global concern, and in recent years, there has been a significant improvement in the number of countries identified as being iodine-sufficient. This review considers the best strategies to ensure iodine sufficiency among breastfeeding women and their infants.
Recent Findings
Fortification strategies to improve iodine intake have been adequate for school-age children (SAC); however, often, iodine deficiency remains for breastfeeding women and their infants. Daily supplementation with iodine is not an ideal strategy to overcome deficiency.
Summary
Countries defined as iodine-sufficient, but where pregnant and breastfeeding women have inadequate intake, should consider increasing salt iodine concentration, such that the median urinary iodine concentration of SAC can be up to 299 µg/L. This will ensure adequate intake for mothers and infants, without SAC being at risk thyroid dysfunction. Consensus is required for thresholds for iodine adequacy for breastfeeding women and infants.
... Számos esetben vizsgálták a jódhiány és az intellektuális fejlődés közötti kapcsolatot. A jóddal nem megfelelően ellátottak esetében szignifikánsan alacsonyabb IQ-t mértek, aminek mértéke 5-13,5 IQ pont is lehet 3,4,5 . A jódbevitelt azonban egyensúlyban kell tartani, hiszen a jódbevitel és a pajzsmirigyzavarok közötti kapcsolat U alakú, azaz mind a nem megfelelő, mind a túlzott jódbevitel pajzsmirigyzavarokat okozhat arra érzékeny egyéneknél. ...
A jódhiány továbbra is jelentős közegészségügyi problémát jelent világszerte; különösen a várandósok és a kisgyermekek veszélyeztettek. Ugyanakkor mind az elégtelen, mind a túlzott jódbevitel is károsan befolyásolhatja a pajzsmirigy működését. A szervezet jódellátottságát a nemzetközi ajánlások alapján a vizelet jódkoncentráció (UIC) alapján lehet vizsgálni, ami nemcsak a jódhiány kimutatására, hanem a túlzott bevitel felderítésére is alkalmas módszer. Ezen ismeretek birtokában, rendszeres humán biomonitoring vizsgálatok (HBM) végzésével az adott populáció aktuális ellátottsági szintjéhez lehet igazítani a jódbevitel mértékét, így nemcsak a jódhiány, hanem a túlzott jódellátottság okozta betegségteher is megelőzhető. Az InAirQ projekt (2016-2019) keretében 9 magyarországi település 23 kiválasztott iskolájában, összesen 393 9-11 éves gyermektől gyűjtöttünk vizeletet egy alkalommal. A vizeletminták jód koncentrációját Sandell-Kolthoff reakción alapuló spektrofotometriás módszerrel határoztuk meg. A Jász-Nagykun-Szolnok megyei települések iskoláiban a vizelet mintavételekkel egy időben több ponton vett ivóvízminták jodid koncentrációját is mértük a Nemzeti Népegészségügyi Központ (NNK) laboratóriumában. Az analitikai méréseket kérdőíves felmérés egészítette ki, melynek célja a jódbevitel lehetséges forrásainak azonosítása volt. A karcagi és Karcag környéki településeken élő gyermekek vizeletének medián jód koncentrációja 629 µg/l (95% CI: 557-667); ez a WHO definíciója szerint túlzott jódellátottságot jelez, ugyanakkor az egyéb településeken élő, vizsgálatba bevont gyermekek esetében a medián vizelet jódkoncentráció 165,5 µg/l (95% CI: 148-186) volt, ami megfelelő jódellátottságra utal. A Karcagon és a környező településeken vett ivóvízmintákban átlagosan 540 µg/l jodid- koncentrációt mértünk, 580 µg/l mediánnal. A többi település esetében, az NNK 2017. évben végzett országos felmérése alapján 20 µg/l ivóvíz jodidion tartalommal számoltunk. Az átlagos vízfogyasztással súlyozott ivóvíz jodidion-koncentráció és UIC között szignifikáns pozitív összefüggést (R=0,83, p<0,0001) találtunk. Ezen eredmény és a kérdőívek elemzése alapján valószínűsíthető, hogy Karcagon és a környező településeken a magas jódtartalmú ivóvíz- fogyasztás következménye az itt élő gyermekek emelkedett vizeletjód koncentrációja. Az érintett településeken élő gyermekek esetében javasoljuk az étrendi jódbevitel mérséklését, valamint az esetleges jódpótlás megszüntetését. Meg kell vizsgálni továbbá az ivóvíz jodidkoncentráció csökkentésének a lehetőségét, míg az ország egyéb részén élő gyermekek esetében a jódozott só szélesebb körű felhasználását kell elérni. Az aktuális jódellátottsági helyzet értékelése érdekében továbbra is javasoljuk a rendszeres, egész országra kiterjedő szűrővizsgálatok, illetve HBM vizsgálatok végzését (iskolai szűrések, pajzsmirigy-, vizelet és vérvizsgálatok, várandósok, szoptató anyák vizsgálata stb.).
... Meta-analyses have estimated a mean intelligence reduction of 12-13.5 points in children living in regions with endemic iodine deficiency. 10,11 However, the studies included in the metaanalyses were cross-sectional comparisons between communities with different iodine intakes, and therefore it is impossible to distinguish between the contributions of childhood and gestational deficiency in the reported estimates. 12 An intervention trial in a region with moderate iodine deficiency has supported the importance of childhood iodine sufficiency, identifying improved cognitive abilities in school-aged children with repleted iodine. ...
Background
Severe iodine deficiency adversely affects neurodevelopment; however, evidence regarding the association of non-severe deficiency and child cognitive functioning is inconclusive.
Methods
This prospective mother-child cohort study was nested in a population-based nutritional supplementation trial in Bangladesh (Maternal and Infant Nutrition Interventions in Matlab [MINIMat]). Participants with data on cognitive abilities at 5 and 10 years of age (n = 1530) and at least one measurement of urinary iodine concentration (UIC) (gestational week 8, 5, and 10 years) were selected. Cognitive abilities were assessed using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-III) and Wechsler Intelligence Scale for Children (WISC-IV). UICs were measured with inductively coupled plasma mass spectrometry and thereafter adjusted for specific gravity.
Results
Median UICs in our population: (282 μg/L [pregnancy]; 406 μg/L [5 years]; 294 μg/L [10 years]) indicated that iodine intake corresponded to above ‘adequate’ or even ‘excessive’, according to the WHO classification. Maternal ‘UIC <150 μg/L’ was associated with lower full-scale and verbal scores at 5 and 10 years, although the associations were weakened in the fully adjusted models. A tendency of decreased verbal scores was also observed for maternal ‘UIC ≥500 μg/L’ but not for the corresponding child iodine category (≥300 μg/L). Child ‘UIC <100 μg/L’ was associated with lower processing speed (B=-3.1, 95% CI [-6.2, -0.1]; P-value = 0.041) compared with the reference group (100 μg/L≤ UIC <300 μg/L).
Conclusions
Current findings add to the growing evidence of a causal association of early-life iodine intake with cognitive development, indicating that low iodine intake during childhood is associated with reduced processing speed and non-optimal gestational iodine intake is weakly associated with slightly poorer verbal development outcomes.
... But pregnant women, lactating mothers, and neonates are considered the most vulnerable groups. A meta-analysis of Chinese studies, 2005 comparing the intelligence quotient (IQ) of children living in naturally iodine-sufficient areas to children living in severely iodine-deficient areas found that the 12.45 points were on average higher IQ of iodine-sufficient children [8]. ...
Background: Iodine is a necessary element of the hormones produced by the thyroid gland. Basically, thyroglobulin (Tg), a thyroid-specific protein, that reflects the size of the thyroid gland, is usually considered a biomarker of urinary iodine status of several patients. But in Bangladesh, we do have not enough information regarding the sensitivity, specificity, and predictive value of thyroglobulin in determining iodine deficiency among simple diffuse goiter patients. Aim of the study: The aim of this study was to evaluate the sensitivity, specificity, and predictive values of thyroglobulin in determining iodine deficiency among simple diffuse goiter patients. Methods: This cross-sectional observational study was conducted at the Department of Endocrinology, Bangabandhu Sheikh Mujib Medical University (BSMMU), and Dhaka Bangladesh. The study was conducted during the period from May 2014 to March 2016. The targeted sample size of this study was between 39 and 90 and the final sample size was finalized as 87. A purposive sampling technique was used to select 87 patients with simple diffuse goiter attending the outpatient department of the mentioned hospital. Results: In this study, we did not find any statistically significant difference in urinary iodine between the different cut-off values of serum thyroglobulin at 14.46 (ng/ml). Similarly, there was not any statistically significant difference in urinary iodine levels at different cut-off values of thyroglobulin. Thyroglobulin had a high negative predictive value and comparatively low positive predictive value in determining iodine deficiency, at 98.51% and 30% respectively. Serum thyroglobulin had 85.71% sensitivity and 82.50% specificity. Thyroglobulin also had a high negative predictive value at 98.51%, but a low positive predictive value at 30%. The overall accuracy of thyroglobulin as an indicator for iodine deficiency was 82.76%. Conclusion: Thyroglobulin seems to have an inverse association in iodine deficiency state and a positive association in over sufficient state with UI. The overall sensitivity of thyroglobulin was satisfactory but the specificity was found very low. Considering the urinary iodine as the gold standard, basically, the positive predictive value of thyroglobulin was found very low but the negative predictive value was found very high.
... Iodine intakes of <25 μg per day in pregnancy could lead to children being born with cretinism, characterized by severe intellectual disability, deaf-mutism and stunted growth 112,113 . Meta-analyses have shown that children born to women with severe iodine deficiency have an IQ lower by 7.4 to 12 points compared with children born to iodine-sufficient women 114,115 . ...
Thyroid disorders are prevalent in pregnant women. Furthermore, thyroid hormone has a critical role in fetal development and thyroid dysfunction can adversely affect obstetric outcomes. Thus, the appropriate management of hyperthyroidism, most commonly caused by Graves disease, and hypothyroidism, which in iodine sufficient regions is most commonly caused by Hashimoto thyroiditis, in pregnancy is important for the health of both pregnant women and their offspring. Gestational transient thyrotoxicosis can also occur during pregnancy and should be differentiated from Graves disease. Effects of thyroid autoimmunity and subclinical hypothyroidism in pregnancy remain controversial. Iodine deficiency is the leading cause of hypothyroidism worldwide. Despite global efforts to eradicate iodine deficiency disorders, pregnant women remain at risk of iodine deficiency due to increased iodine requirements during gestation. The incidence of thyroid cancer is increasing worldwide, including in young adults. As such, the diagnosis of thyroid nodules or thyroid cancer during pregnancy is becoming more frequent. The evaluation and management of thyroid nodules and thyroid cancer in pregnancy pose a particular challenge. Postpartum thyroiditis can occur up to 1 year after delivery and must be differentiated from other forms of thyroid dysfunction, as treatment differs. This Review provides current evidence and recommendations for the evaluation and management of thyroid disorders in pregnancy and in the postpartum period.
... 3 A fetus may be even more sensitive to environmental insults. [4][5][6][7] Given that the global prevalence of obesity among women increased from 6% in 1975 to 15% in 2016, 8 an area of ongoing interest is the extent to which higher maternal weight status in pregnancy might influence the developing brain. ...
Importance
Prenatal experiences can influence fetal brain development.
Objective
To examine associations of maternal prenatal body mass index (BMI) with cognition and behavior of offspring born full-term.
Design, Setting, and Participants
This cohort study examined follow-up data from a breastfeeding promotion intervention at 31 hospitals and affiliated polyclinics in the Republic of Belarus. Participants included 11 276 children who were evaluated from birth (1996-1997) to adolescence (2017-2019), with maternal BMI information available in prenatal medical records.
Exposures
Maternal BMI, calculated as weight in kilograms divided by height in meters squared, after 35 weeks gestation; secondary analyses examined maternal BMI at other time points and paternal BMI.
Main Outcomes and Measures
Trained pediatricians assessed child cognition with the Wechsler Abbreviated Scales of Intelligence (WASI) at 6.5 years and the computerized self-administered NeuroTrax battery at 16 years, both with an approximate mean (SD) of 100 (15). Parents and teachers rated behaviors at 6.5 years using the Strengths and Difficulties Questionnaire (SDQ, range 0-40). Mixed-effects linear regression analyses corrected for clustering, adjusted for the randomized intervention group and baseline parental sociodemographic characteristics, and were considered mediation by child BMI.
Results
Among 11 276 participants, 9355 women (83%) were aged 20 to 34 years, 10 128 (89.8%) were married, and 11 050 (98.0%) did not smoke during pregnancy. Each 5-unit increase in of maternal late-pregnancy BMI (mean [SD], 27.2 [3.8]) was associated with lower offspring WASI performance intelligence quotient (IQ) (−0.52 points; 95% CI, −0.87 to −0.17 points) at 6.5 years and lower scores on 5 of 7 NeuroTrax subscales and the global cognitive score at 16 years (−0.67 points; 95% CI, −1.06 to −0.29 points). Results were similar after adjustment for sociodemographic characteristics, pregnancy complications, and paternal BMI and were not mediated by child weight. Higher late pregnancy maternal BMI was also associated with more behavioral problems reported on the SDQ by teachers but not associated with parent-reported behaviors (externalizing behaviors: 0.13 points; 95% CI, 0.02 to 0.24 points; and total difficulties: 0.14 points, 95% CI, −0.02 to 0.30 points). Results were similar for maternal BMI measured in the first trimester or postpartum. In contrast, higher 6.5-year paternal BMI was associated with slightly better child cognition (WASI verbal IQ: 0.42 points; 95% CI, 0.02 to 0.82 points; NeuroTrax executive function score: 0.68 points; 95% CI, 0.24 to 1.12 points) and fewer teacher-reported behavioral problems (total difficulties: −0.29 points; 95% CI, −0.46 to −0.11 points).
Conclusions and Relevance
This cohort study supports findings from animal experiments and human observational studies in settings with higher maternal BMI and obesity rates. Higher maternal prenatal BMI may be associated with poorer offspring brain development, although residual confounding cannot be excluded.
... The findings also underscore the need to explore strategies that can possibly reverse the effects of high iodine on low intelligence of children, including the need to identify populations at risk for appropriate action, evidenced by studies which demonstrated that the effect of low iodine concentration on low intelligence can be reversed [47]. ...
The purpose of this meta-analysis is to comprehensively investigate the effect of iodine excess on children’s intellectual development in areas with high iodine levels in their drinking water. We systematically searched the electronic databases and identified 17 publications (16 in Chinese and 1 in English) on the effect of iodine excess on children’s intelligence published between January 31, 1985, and January 31, 2020. This meta-analysis included 14,794 children from 28 studies. The results showed that compared with the control group, the intelligence level of children in the high iodine group reduced significantly by 1.64 points (WMD=−1.64; 95% CI (−3.225, −0.049), Z=2.02, P<0.05). Subgroup analyses were performed according to the water iodine concentration, water iodine concentration of the control group, the intelligence test method, and regions of China (i.e., north and south). We noted that when the water iodine concentration was <300μg/L, 301–600μg/L, 600.1–900μg/L, and >900μg/L, the intelligence level of the high iodine groups decreased by varying degrees, although not statistically significant (all P>0.05). The water iodine concentration of the control group was divided into two groups (<150 μg/L and <100 μg/L) and the heterogeneity analysis showed that the heterogeneity of the control group decreased significantly when the concentration of water iodine was <150 μg/L, I2 = 67.3%, P<0.001, which indicated a potential source of heterogeneity. The analyses by test method showed that among the studies which used the China Joint Raven’s test, the intelligence level of children in the high iodine group was 0.86 points lower than in the control group (P>0.05). Conversely, we observed that among the studies which used the China Binet intelligence test and the binaphthalene intelligence test of Tanzhida in Japan to evaluate children’s intelligence level, the intelligence level of children in the high iodine groups was significantly lower (3.65 points and 8.0 points, respectively) compared with the control groups (P<0.05). The analysis of the regions of China demonstrated that whereas the reduction in children’s intelligence level from excess iodine in the north of China was not statistically significant (WMD=−0.16, 95% CI (−2.18, 1.85), P>0.05), the association was statistically significant in the southern part of China (WMD=−1.86, 95% CI (−3.57, −0.09), P<0.05). This study found that high iodine concentration was statistically significantly associated with a decline in intelligence level in children. Comparatively, the intelligence level of children who were exposed to high iodine concentrations reduced significantly by 1.64 points. These findings have public health implications.
... Anaemia is reported to decrease GDP by 4% [23]. Iodine deficiency reduces IQ by 13 points [27]. Poor physical growth resulting from poor nutrition is associated with life-long predisposition to disease, increasing absenteeism from work, low labour productivity and reduced income. ...
Achieving food and nutrition security is fundamental to the Sustainable Development Goals (SDGs) due to its strong interdependence with economic growth and development. Eradicating hunger and all forms of malnutrition (SDG 2) remain high on the global agenda and is at the forefront of high panel deliberations because poor dietary intake has long term negative consequences on individuals and economic advancement. The goal to end hunger and malnutrition can be achieved when food and nutrition insecurity is properly tackled through investment in agriculture parallel to economic and social protection programmes. In Ghana, about 1.5 million of the population are estimated to be food insecure while undernutrition, overnutrition and micronutrient deficiencies persist across the life stages. Challenges to food and nutrition security in Ghana have been identified as: poverty, climate change, rapid urbanization and population growth, gender inequalities and poor infrastructure. Poor economic growth, health, education, hygiene and environmental exploitation are implications of these challenges. Addressing these implications sets long-term foundation for the development of the nation by prioritising policies that are nutrition sensitive which directly address the complexity of malnutrition. The level of food and nutrition insecurity in Ghana can be reduced through a national commitment towards addressing the four pillars of food security coupled with programmes that bring about resilience through sustainable systems. To this end, intervention programmes have been introduced by government to reduce the poverty burden on households. These programmes are in the form of social interventions, governmental flagship projects, and research-driven agricultural interventions to improve yield that withstand the effect of climate change. This review is aimed to present the food and nutrition security situation in Ghana and emphasised the challenges that exacerbate the problem while bringing to light the nutritional implications to national development. It is hoped that the recommendations from this review will help the government in achieving food and nutrition security in Ghana.
... Children in IDD endemic areas have a higher risk of experiencing cognitive-developmental impairment. Iodine is a micronutrient essential in brain development (Qian et al., 2005;van den Briel et al., 2000). Iodine deficiency is not the only problem associated with intellectual deficit in the endemic IDD. ...
The multifactorial risks that accompany IDD (Iodine Deficiency Disorders) aggravate cognitive development deficits in children. The most important factors are poor cognitive stimulation and parenting. This study aimed to analyse the impact of parenting training on maternal skills to mediate cognitive development in children. The study was quasi-experimental pre-post with a control group design. A total of 78 mothers and their children, aged four to five years, from Purworejo participated in the research. Palpation to assess maternal goiter status and Mother-Child Picture-Talk Task (MCPTT) assessed the ability to perform cognitive mediation in children. The Smart Mother Class, a parenting skill intervention, was given for six months (16 meetings), each lasting 60-90 minutes. The risk of low family resources, both economic and caring resources, is indicated by the work and education of the fathers and mothers. Most mothers and fathers have elementary school education and below (60.3). The result show that three months after the intervention there was a significant effect at the positive level, and at six months, the intervention group showed a significant improvement (p< 0.001). Parenting training in low parenting resource settings could improve maternal skills for mediating cognitive development in pre-school age children.
... Iodine is an essential component for the synthesis of thyroid hormones (THs) which are important for the growth and maturation of fetus and the development of brain [1]. Sufficient iodine intake and TH levels are essential to prevent the birth abnormality of the offspring [2,3]. Previous studies have shown that the increased risk of abortus, stillbirth, low birthweight infants, macrosomia, preterm delivery, neurological damage, and intellectual impairment are closely related to maternal iodine deficiency [4][5][6][7]. ...
Background
Iodine plays an important role in pregnancy. How to maintain adequate iodine intake amongst pregnant women in each trimester of pregnancy to prevent adverse birth outcomes in central China is a challenge for clinical practice.
Methods
870 pregnant women and their infants were enrolled in the study. Urinary iodine concentration (UIC) was measured using an inductively coupled plasma mass spectrometry (ICP-MS). Maternal and newborn information were obtained during follow-up. Multinomial logistic regression models were established.
Results
Median UIC of pregnant women was 172 ± 135 μg/L which is currently considered to be sufficient. Multivitamin supplements containing iodine, iodized salt intake and frequent milk intake were significantly associated with higher UIC. Multivariate logistic regression analysis showed that multivitamin supplements containing iodine and milk consumption were risk factors for more than adequate iodine (UIC ≥ 250 μg/L). Iodine-rich diet was significantly related to heavier birthweight, larger head circumference and longer femur length of the newborns while more than adequate iodine intake (UIC ≥ 250 μg/L) was a risk factor for macrosomia. Logistic regression models based on potential risk factors involving iodine containing supplements and iodine-rich diet were established to predict and screen pregnant women with high risk of more than adequate iodine intake among local pregnant women in different trimesters and guide them to supplement iodine reasonably to prevent the risk.
Conclusions
Multivitamin supplements containing iodine and milk consumption were risk factors for maternal UIC ≥ 250 μg/L which was a risk factor for macrosomia. Iodine monitoring models were established to provide guidance for pregnant women to reduce the risk of more than adequate iodine intake, thereby contributing to reduce the risk of having a macrosomia.
... Children born to iodine deficient mothers experience average deficits of 12.5-13.5 IQ points (Bleichrodt and Born 1994;Qian et al 2005). The TLFNS reports prevalence of iodine deficiency (urinary iodine excretion (UIE)) 17 <100 mcg/dL) among non-pregnant mothers of 26.7% and a median urinary iodine concentration of 170 ug/L among non-pregnant, non-lactating women. ...
... This study highlighted that dietary iodine supplements not only have no harmful effect on the neurodevelopment of the children, they may even be bene icial. In another study Qian, et al. in a meta-analysis of 37 studies involving 12292 children, have shown that those children whom mothers were supplemented with iodine before and during pregnancy, had more Intelligent Quotient (IQ) than those without iodine supplementation [89]. In a randomized placebo-controlled trial by Simona Censi, et al. it has been shown that initial iodine supplementation of 225 μg/day in pregnant women from the irst trimester helps to prevent thyroid derangement and may avoid detrimental impact of mild-to-moderate iodine de iciency on fetal neurodevelopment [90]. ...
During the last few decades painstaking efforts have been made to eliminate iodine deficiency through the world. Nowadays in regions where dietary iodine intake is adequate or borderline, the main focus is increasing dietary iodine supply in the target population during pregnancy and the first years of life. Severe iodine deficiency during pregnancy increases the risk of irreversible brain damage, intellectual disability, neurologic abnormalities, stunted growth, increased pregnancy loss, infant mortality, impairments in child development and cretinism. The potential effects of mild-to-moderate iodine deficiency are debated. Results from animal studies and observational human studies indicate that maternal mild-to-moderate iodine deficiency disturbs thyroid function in pregnancy and it also may affects fetal neurodevelopment. The effect of supplementation of iodine on thyroid function of pregnant women and their newborn, neurodevelopment of infants and cognitive performance of children have been investigated using iodine nutrition in pregnancy, based on median urinary iodine concentration. However they have found conflicting results regarding the benefits or harms of iodine supplementation in pregnancy. Although many epidemiological, interventional and clinical studies have supported the association between thyroid function in pregnant women and later psychomotor and mental development of their children, the effect of iodine supplementation in pregnant women on neurodevelopment of children is inconclusive. Even in areas with well-established universal salt iodization program, pregnancy could be at risk of having iodine deficiency and despite WHO/ICCIDD/UNICEF recommendation which believe that dietary iodine fortification during pregnancy depends primarily on the extent of pre-existing iodine deprivation, systematic dietary fortification needs to be implemented in this vulnerable group. However, iodine supplementation of mildly iodine deficient pregnant women may not have beneficial effects in their thyroid function or neurodevelopment of their children.
... En el niño la deficiencia crónica de yodo causa hipotiroidismo congénito, cretinismo y deficiencias neuromotoras, intelectuales, conductuales y cognitivas, lo que lleva a problemas de aprendizaje, retraso mental irreversible, alteraciones en el crecimiento y defectos psicomotores (3,(9)(10)(11)(12)(13). Deficiencias leves en las concentraciones de hormonas tiroideas maternas pueden reducir el peso del recién nacido (14,15) y deficiencias en la ingesta nutricional de yodo durante la infancia reducen el coeficiente intelectual de los escolares (16). Los métodos de evaluación del estado nutricional del yodo recomendados para la gestante han sido la cuantificación de la concentración urinaria media de yodo y la valoración clínica de bocio. ...
Objetivo:
Evaluar la prevalencia de yodo deficiencia y de bocio en mujeres indígenas gestantes de cinco áreas no metropolitanas en Colombia.
Materiales y métodos:
Estudio de corte transversal descriptivo. Se incluyeron mujeres embarazadas de cualquier edad gestacional sin condiciones patológicas del embarazo, atendidas en los centros de salud comunitarios o en sus residencias. Se excluyeron aquellas con comorbilidades presentes al momento del embarazo y también a quienes recibían suplementos con yodo. Muestreo aleatorio simple. Se midieron las características sociodemográficas y obstétricas, la concentración de yodo en orina y la presencia de bocio de acuerdo a la metodología de la Organización Mundial de la Salud. Se realizó un análisis descriptivo.
Resultados:
189 gestantes indígenas fueron candidatas a ingresar al estudio, de las cuales 2 no aceptaron participar y 62 tenían criterios de exclusión, finalmente se analizaron 125. La concentración urinaria de yodo tuvo una mediana de 184,4 μg/L (min-max: 12,0-390,0). Un total de 42 gestantes (33,6%) tenían yodo deficiencia (< 100 μg/L) y se evidenció bocio (grado 1-2) en 43 (34,4%). No se identificó bocio grados 3 o 4.
Conclusiones:
Embarazadas indígenas residentes en áreas no metropolitanas evidenciaron alta prevalencia de bocio y yodo deficiencia. Se requiere evaluar los efectos materno-perinatales e implementar intervenciones nutricionales.
... Aside from the mentioned studies, evidence suggests that in marginally iodine-deficient areas, some maternal thyroid indices can be improved by iodine supplementation. Qian et al. in a meta-analysis of 37 studies on 12,292 children showed that children, whose mothers received iodine supplementation before and during pregnancy, had a higher intelligence quotient (IQ) than those without iodine supplementation [37]. A systematic review of nine RCTs by Taylor et al. [38] showed that in seven RCTs, iodine treatment was associated with a significant increase in the maternal urinary iodine excretion. ...
Background
Although Iran has been considered iodine replete since 2000, the first national survey of iodine intake among Iranian pregnant women in 2014 indicated that despite the adequate intake of iodine by the general population, this vulnerable group has moderate iodine deficiency. Therefore, in this national cross-sectional interventional study, we aimed to assess the iodine intake and thyroid function of Iranian pregnant women 2 years after implementing national iodine supplementation for this vulnerable group.Materials and methodsIn this cross-sectional study, we conducted a national interventional survey of pregnant women. A total of 1200 pregnant women (400 women from each trimester) from 12 provinces of Iran were recruited from the antenatal care clinics from October 2018 to March 2019. The median urinary iodine concentration (MUIC), as an indicator of iodine status in three spot urine samples, was measured, along with the serum total T4 (TT4), thyrotropin (TSH), thyroglobulin (Tg), thyroid peroxidase antibody (TPO-Ab), and iodine content of household salt.ResultsThe mean age of the cohort was 28 ± 6.2 years, with the mean gestational age of 22.7 ± 13.0 weeks. The overall MUIC (IQR) of pregnant women was 188 µg/L (124.2–263 µg/L). Also, the MUICs in the three trimesters of pregnancy were 174 µg/L (110–254), 175 µg/L (116–251), and 165 µg/L (114–235), respectively. The MUICs ≥ 150, 100–149, and < 100 µg/L were found in 63, 19.8, and 16.2% of the subjects, respectively. The mean TT4 level was 12 ± 4.5 µg/dL, and the median (IQR) level of TSH was 2.37 mIU/L (1.66–3.18 mIU/L). According to our local reference range, 118 (10.5%) pregnant women had subclinical hypothyroidism, 6 (0.53%) women had isolated hypothyroxinemia, and 65 (5.7%) women were TPO-Ab positive. Also, the median (IQR) level of Tg was 10.08 µg/dL (5.7–20.4 µg/dL), and the median iodine content of household salt was 29.6 µg/g; the iodine content was ≥ 30 µg/g in 85% of household salt. The results showed that more than 95% of households were under iodized salt coverage.Conclusion
The results of this study indicated that iodine supplementation with at least 150 µg of iodine per day improved the iodine intake of pregnant women. Except for subclinical hypothyroidism, the prevalence of clinical hypothyroidism, clinical/subclinical thyrotoxicosis, TPO-Ab positivity, and isolated hypothyroxinemia decreased significantly, which emphasizes the importance of iodine supplementation during pregnancy.
... Pregnant woment are susceptible group to get more health disorders during their pregnancy. The normal of thyroid function is important to achieve a healthy pregnancy that will ensure the fetus grows and develops optimally (1,9,10). Therefore, the study to assess thyroid function, among pregnant women in the two different geographic areas that had affected by previous history of iodine deficiency is important to formulate IDD prevention program and policy. ...
Iodine deficiency in pregnant woman can affect growth and development of fetus. People who live in an area that had affected by previous iodine deficiency may continuously affect by abnormal thyroid function. The aim of the study is to assess thyroid function, that was measured by the concentrations of thyroid stimulating hormone, and its relationships with free thyroxine (fT4) among pregnant women in the two different geographic areas with previous history of iodine deficiency in Magelang, Central Java, Indonesia. Cross-sectional study was conducted in two types of location (replete and non-replete area) in Magelang, Central Java, Indonesia. A total of 243 aged between 15–45 y old with no pregnancy complication from two different geographics areas of iodine replete and sufficient were include in study. Blood biochemical markers such as free thyroxine hormone and thyroid stimulating hormone were assessed by Elisa method. Median of fT4 in non-replete and replete area was 1.18 (0.63–3.5) ng/dL; 1.12 (0.37–1.95) ng/dL, respectively. Whilst, median of TSH in replete area was 1.27 (0.09–8.21) ng/dL and non replete area was 1.3 (0.01–8.67) ng/dL. Correlation between fT4 and TSH showed significat relationship in non-replete area, r=−0.39 (<0.05), but it was not significant in replete area, r=−0.08 (>0.05). In addition, scatter plot showed the relationship between fT4 and TSH levels pattern in the replete area more widespread. Pregnant womens who live in areas that had affected severe iodine deficiency intake may have abnormal thyroid function but it still euthyroid maintain by adequate iodine intake.
... Ciddi ve orta derecede iyot yetersizliğinin görüldüğü bölgelerde gebenin iyot yetersizliği ile çocuğun nörokognitif gelişimi arasında ilişki olduğu gösterilmiştir (75). Bu bölgelerde gebelere verilen iyot desteğinin çocukların nörogelişimi üzerinde olumlu etkiler sağladığı da belirlenmiştir (76,77). Çok hafif iyot yetersizliğinin bile çocuğun zekâ düzeyi ve işitsel fonksiyonunda bozukluklara yol açabileceğini gösteren kanıtlar mevcuttur (75,78). ...
Gebelik sürecinde artan gereksinimler dolayısıyla; özellikle bazı mikro besin ögelerinin besin desteği olarak alınması ve böylece yetersizlik ile ilişkili risklerinin en aza indirilmesi, maternal ve fetal sağlığın korunmasında büyük öneme sahiptir. Gebelikte, besin ögelerinin ciddi veya orta düzeyde yetersizliğinde, hayat kurtarıcı nitelikte olan destekler; hafif yetersizlik veya maternal depoların yeterli olduğu koşullarda, çeşitli riskleri de beraberinde getirmektedir. Doğumsal anomalilerin önlenmesinde etkisi kanıtlanmış olan folik asitin maternal dönemde fazla alımı durumunda kanserojeniteyi tetikleyebileceği, çinko emilimini olumsuz etkileyebileceği, B12 vitamini eksikliğinin tanısında ve tedavisinde gecikmelere yol açabileceği, çocukluk çağı astım, alerji riski ile ilişkili olabileceği görülmüştür. Eksikliği fetal anomaliler ile ilişkilendirilen bir diğer vitamin olan B12’nin toksik etkisi bildirilmemekle birlikte literatür taramasında fazla alımı durumunda alerjik reaksiyonlar gösteren bir vaka raporuna rastlanmıştır. Yenidoğan hipokalsemisi ve raşitizmin önlenmesinde etkili D vitamini desteğinin fazla alımı teratojen etki gösterebilir. İyot yetersizliği ile ilişkili kretenizm gibi hastalıkların önlenmesinde etkili olan iyot desteğinin fazla alımının gebenin tiroid disfonksiyonuna, gebelikteki subklinik ve aşikâr hipotiroidizm prevalansında artışa yol açabileceği ve bebeğin psikomotor gelişimini olumsuz etkileyebileceği belirtilmiştir. Gebelikte önerilen dozlarda besin desteklerinin kullanımı uygundur ancak yetersizliğin önlenmesi kadar fazla alım konusunda da dikkatli olunmalıdır. Bu derlemede; gebelikte yaygın olarak kullanılan folik asit, B12 vitamini, D vitamini ve iyot besin desteklerinin fazla alımına ilişkin riskler tartışılmıştır.
... 2,[5][6][7][8][9][10][11] Under severe conditions, iodine deficiency is responsible for a mean IQ loss of 13.5 points in children. 2,[11][12][13] At a population level, iodine deficiency hurts a country's overall health and productivity and hinders its socioeconomic development. 14 Globally, about 2 billion people are affected by iodine deficiency. ...
Background: Iodine deficiency is a major public health concern throughout the world. Goiter is the most visible sign of iodine deficiency. In Ethiopia, a study finding regarding the prevalence of goiter among school-age children is inconsistent and
highly variable.
Objectives: To estimate the pooled prevalence of goiter among school age children in Ethiopia.
Methods: Three international databases (MEDLINE/Pub-Med, Google Scholar and Science Direct) were systematically searched. Besides, the reference sections of identified articles were searched to increase the chance of detecting missed articles in gray literature. STATA Version 14 statistical software was used to conduct a meta-analysis. The pooled prevalence with a 95% confidence interval was displayed using the forest plot. A random-effect meta-analysis model was used to compute the pooled prevalence, and The Cochrane Q test statistics and I2 test were used to assess the heterogeneity of the studies.
Results: A total of 14 studies fulfilled the inclusion criteria and included in this systematic review and Meta-analysis, with a
total sample size of 26,282. The finding of this systematic review revealed that the pooled prevalence of goiter among school-age children was 42.9% (95% CI: 38.8–46.9). The highest prevalence of goiter (46.7%) was observed in Oromia region and the lowest (26.3%) was observed in Benishangul-Gumuz region.
Conclusions: This review finding revealed that more than two in five of the school children in Ethiopia suffer from iodine deficiency disorder as manifested by the goiter rate.
... Most research on iodine deficiency has focused on IQ in childhood, with a clear consensus on the detrimental impact. For example, 2 meta-analyses 90,91 indicated there to be a general loss of 12.5-13.5 IQ points in severely iodinedeficient populations compared with non-iodinedeficient groups. ...
Executive functions refer to a set of higher-order cognitive processes involved in the control and organization of information to serve goal-directed behaviors. Skills in executive functioning are developed throughout childhood and adolescence and have been shown to be predictive of academic achievement. The coordination of these complex processes is critically dependent on brain maturation and connectivity, including key neurodevelopmental processes like myelination and synaptogenesis. Among other factors, research highlights the influential effect of nutrition and diet on these neurodevelopmental processes, which may impact executive function performance in healthy and deficient populations. This review considers the research to date on the role of key nutrients that have been identified for executive function development and their underlying neurophysiological processes in school-aged children.
... Patnam, 2011), contribuent à un capital humain réduit et augmentent les risques auxquels l'enfant sera confronté durant sa vie.Ces déficits persistent durant la vie adulte. Ainsi, les carences en iode sont la principale cause de retards mentaux et de lésions cérébrales(Qian et al., 2005).Maluccio,Behrman, Flores, & Martorell, 2008). Les chercheurs et praticiens du développement s'accordent désormais à reconnaître que la petite enfance est une étape fondamentale du développement(Heckman, 2006, Shonkoff & Phillips, 2000.Les premières années de vie d'un enfant sont une fenêtre d'opportunité pour construire les bases solides du développement humain dans toute la vie.Le principal objectif de cette recherche est d'estimer et d'analyser les inégalités d'opportunités parmi les enfants de moins de 5 ans et d'identifier les principaux déterminants de ces inégalités afin de fournir des informations utiles aux décideurs publics. ...
Early childhood is the most important time for human development. However, countries tend to under-invest in this stage of development, particularly in the Middle East and North Africa (MENA). Children are facing unequal opportunities to develop because of the circumstances of their birth. This project analyzes inequality of opportunity in early childhood development in three Southern and Eastern Mediterranean countries (Algeria, Morocco and Tunisia) and three countries from non-EU Eastern Europe (Bosnia, Serbia and Ukraine). The findings demonstrate that there is substantial inequality of opportunity starting early in life. A variety of circumstances impact early inequality, with wealth, mother’s education, and geographic differences all contributing substantially.
... Initially, to prevent goiters, iodine was added to table salt (CDC Iodine). Iodine supplementation continues as a population's intelligence declines without it (Qian 2005). Fortified breakfast cereals, canned, frozen and processed meals were developed with nutritional labels allowing consumers to select foods to meet nutritional needs for them, their families and institutional consumers (schools, hospitals, and restaurants). ...
For centuries, some crops have been harvested before physiological maturity especially vegetables, vegetable greens and sprouts, grapes, fruits, berries, and alfalfa, grasses and various field crops as silage for livestock feed. However, besides sweetcorn, few field crops are harvested green at high moisture. It is possible to mechanically, genetically, and chemically change (trick) plants like corn and sorghum to retain nutrients, especially sugars (sucrose, fructose and glucose), accumulated in stalks and leaves when seed set is not possible. At approximately 100 days after planting, green harvested field crop nutrients and/or ethanol can be processed at or near the field and pumped via pipeline within 24-72 hours. Unused fiber (carbon), nutrients (nitrogen, protein) and liquids can be retained or returned to the field improving the environment with better water, pest and nutrient management, organic matter retention, erosion prevention, and carbon capture to enhance soil structure. Harvesting field crops in temperate to tropical climates before maturity allows multiple crops to be planted and utilized in the same growing season. It would be adjustable to a changing climate while increasing total annual food production.
... Iodine deficiency disorders (IDDs) occur from the fetal stage to adulthood; pregnant women with iodine deficiency may experience hypothyroxinemia, and the fetus may suffer congenital anomalies, cretinism or endemic neurocognitive insufficiency. 1,2 Infants and adolescents with iodine deficiency may experience subclinical hypothyroidism or goiter, altering their neurological development and intelligence quotient (IQ), 3,4 while toxic nodular goiter and hyperthyroidism have been reported in adults. 5 In order to prevent IDDs, the World Health Organization (WHO) and other agencies recommended universal salt iodization in 1993. ...
Introduction
Deficient or excess iodine intake has effects on human health. Assessment of the prevalence and risk factors in children can therefore support effective prevention or treatment.
Method
A cross-sectional probabilistic study in 631 children aged 5 to 12 years in whom iodine levels were measured in urine and salt samples. Results are reported by type of location and indigenous condition. Association of these variables to urinary iodine levels was assessed using a binary logistic regression.
Results
Median urinary iodine level was 278.4 μg/L (177.3–360.9, IQR), 13.2% of children assessed had iodine levels <100 μg/L, and 41.8% had values ≥300 μg/L. Indigenous schoolchildren had the greatest risk of urinary iodine levels <100 μg/L (β = 2.29, CI 1.1–4.6, p < 0.05), while children from urban and non-indigenous localities had a high risk of iodine levels >300 μg/L (β = 2.2, CI 1.3–3.9, p < 0.01, and β = 3.8, CI 2.2–6.5, p < 0.01 respectively). Median iodine level in salt was 35.9 ppm (29.1–42.4 IQR), and there were no differences in iodine levels in salt by type of location or ethnicity.
Conclusions
In Mexican schoolchildren living in rural and indigenous areas, iodine levels <100 μg/L have not been eradicated. There was high prevalence of urinary iodine levels ≥300 μg/L in schoolchildren living in urban areas which was associated to high sodium intake from processed food.
... In 2005, a meta-analysis aimed to summarize the evidence regarding the effects of iodine on the intellectual development of Chinese children showed a profound intelligence deficit in children exposed to SID, with a loss of 12.45 IQ points. With an adequate iodine supplementation for mothers before and during gestation, the IQ of their children was increased by 8.7 points (68). Additionally, studies in the Chinese population several decades ago showed that people born and continuing to live in regions of iodine deficiency, even if it is moderate deficiency, had impaired intellectual and neuromotor manifestations across a broad spectrum of severity (60-62, 65, 69, 70). ...
Iodine is a necessary micronutrient for the production of thyroid hormones and normal human development. Despite the significant worldwide strategies for the prevention and control of iodine deficiency, it is still a prevalent public health issue, especially in pregnant women. Severe iodine deficiency during pregnancy and neonatal period is associated with many major and irreversible adverse effects, including an increased risk of pregnancy loss and infant mortality, neonatal hypothyroidism, cretinism, and neuropsychomotor retardation. We will review the impact of severe iodine deficiency on maternofetal, neonatal, and offspring outcomes. We will also discuss its epidemiology, classification of iodine deficiency severity, and current recommendations to prevent iodine deficiency in childbearing age and pregnant women.
... Pregnant and lactating women are the most vulnerable population to iodine deficiency (6). Insufficient iodine intake during pregnancy has a long-term impact on child normal growth, brain development, and intelligence quotient scores (7)(8)(9)(10). Furthermore, iodine deficiency is considered to be a major cause of the most preventable mental impairment worldwide (11,12). ...
Background:
Universal salt iodization (USI) is the most feasible and cost-effective, and equitable, approach to prevent iodine deficiency. Severe maternal iodine deficiency during pregnancy is associated with serious adverse gestational and birth outcomes.
Objectives:
The aim was to assess iodine status and identify independent factors associated with urinary iodine concentration (UIC) among women of reproductive age in Tanzania.
Methods:
This was a weighted, population-based, cross-sectional study in 2985 women of reproductive age (20-49 y) in Tanzania who participated in the Demographic and Health Surveys in 2015-2016 (DHS 2015-2016) and had measured UIC. Multivariable generalized linear regression was used to identify potential factors that were associated with UIC.
Results:
The median UICs among women consuming inadequately iodized salt (93.6 μg/L; 25th and 75th percentiles: 43.1, 197.9 μg/L) and women in the lowest socioeconomic status (92.3 μg/L; 45.6, 194.4 μg/L) were below the WHO-recommended ranges (≥150 μg/L for pregnant women and ≥100 μg/L for nonpregnant women). The results of multivariable models indicated that pregnant women had 1.21 μg/L lower UIC than nonpregnant women (β = -1.21; 95% CI: -3.42, -0.12), breastfeeding women had 1.02 μg/L lower UIC than nonbreastfeeding women (β = -1.02; 95% CI: -2.25, -0.27), and women with no education had a 1.88 μg/L lower UIC compared with those with secondary/highest education (β = -1.88; 95% CI: -4.58, -0.36). Women consuming inadequately iodized salt had 6.55 μg/L lower UIC than those consuming adequately iodized salt (β = -6.55; 95% CI: -9.24, -4.33). The median UIC varied substantially across geographic zones, ranging from 83.2 μg/L (45.9, 165.3) in the Western region to 347.8 μg/L (185.0, 479.8) in the Eastern region.
Conclusions:
Our findings indicated a great heterogeneity in median UIC across regions of Tanzania among women of reproductive age. Poverty, consuming inadequately iodized salt, and lack of education appeared to be the driving factors for lower UIC in Tanzania.
... The PMT model has been used in various settings and sectors (Floyd et al. 2000;Milne et al. 2000), including in the field of functional foods (Cox and Bastiaans 2007;Henson et al. 2008;Mabaya et al. 2010). Here, the focus is on iodine biofortification for children, through surveying their parents and school heads, as there is a clear association between iodine deficiency and school performance (Bougma et al. 2013;Pineda-Lucatero et al. 2008;Qian et al. 2005). Moreover, there is a lack of iodine-rich foods in East-African school feeding programs (Murphy et al. 2007). ...
This chapter provides an overview of two case studies that examine stakeholder reactions toward iodine biofortification in Uganda. The first case applies the protection motivation theory and evaluates the intention of school heads and parents of school‐aged children to include iodine‐biofortified legumes in school feeding programs. The second case study takes a broader scope of stakeholder groups and applies the analytical hierarchy process, a multicriteria decision‐making tool, to understand the stakeholders' evaluation of the relative importance of Strengths, Weaknesses, Opportunities, and Threats (SWOT) factors in implementing agronomic iodine biofortification in Uganda. Results from the two cases demonstrate that stakeholders are generally optimistic about the iodine biofortification strategy to improve iodine intake and address the prevalent iodine deficiency disorders. Both cases provide insights into key factors that need to be considered in implementing iodine biofortification technology in a developing country
... Cretinism and profound brain injuries are serious consequences of severe iodine deficiency during gestation [2]; however, even mild iodine deficiency in pregnancy can result in less favorable outcomes, impairing children's cognition, intelligence quotient, and school performances [3][4][5]. Meta-analyses have revealed that the intelligence quotient of children living in iodine-deficient regions was 6.5 to 12.45 points lower than those residing in iodine-sufficient regions [6,7]. In iodine-deficient regions, iodine supplementation to pregnant women has been shown to reduce cretinism, perinatal death, and infant mortality and improve the indices of maternal thyroid function [8][9][10]. ...
Pregnant women are considered as one of the most vulnerable groups for iodine deficiency. The Nutrition and Health Survey in Taiwan 2013 revealed that the median urinary iodine concentration (UIC) of non-pregnant women of child-bearing age of 15–44 years was 124 μg/L, which was adequate in general, but insufficient according to pregnancy criteria. The aim of this study was to determine the iodine nutritional status of pregnant women in an urban area of Northern Taiwan. A hospital-based cross-sectional survey was conducted in Taipei Veterans General Hospital. Random spot urine samples were collected from January to October, 2018 and UIC was determined by inductively coupled plasma mass-spectrometry. A food frequency questionnaire was also delivered to the participants. The overall median UIC was 225.3 μg/L (IQR: 109.1–514.2 μg/L) for 257 pregnant women ranging from 21–47 years-old. The distribution of UIC was as follows: 35.4% with UIC <150 μg/L, 17.1% with UIC within 150–249 μg/L, 21.8% with UIC within 250–499 μg/L, and 25.7% with UIC ≥500 μg/L. The use of prenatal multivitamin was very common among the participants: 79.4% (n = 204) took multivitamin either every day or less frequently, with 52.5% (n = 135) taking one pill every day, and only 20.6% (n = 53) never took multivitamin during their pregnancy. Other commonly consumed iodine-containing foods were dairy products and fish. Our results indicate that the iodine status in the studied women is adequate. However, efforts are still needed to avoid iodine deficiency as well as iodine excess.
Introduction:
Iodine is an essential mineral for fetal growth and brain development. The aim of this research was to evaluate goiter, iodine deficiency and intrauterine growth restriction in pregnant women of minority ethnic groups in Colombia.
Methods:
A cross-sectional study was performed in six non-metropolitan areas of Colombia.
Results:
A total of 318 Indigenous and Afro-descendant pregnant women were invited to participate: 248 (83.2%) Indigenous and 50 (16.8%) Afro-descendants were studied. The mean age was 24 years (range 13-44 years). Of the women, 130 (43.5%) were from the department of Cauca, 72 (24.1%) were from Córdoba, 28 (9.4%) were from Guajira, 26 (8.8%) were from Sierra Nevada de Santa Marta, 22 (7.4%) were from Amazonas, 16 (5.4%) were from Meta and 4 (1.3%) were from the department of Cesar. A total of 244 (81.8%) were illiterate and 291 (97.7%) were of very low socioeconomic level. Goiter was observed in 69 (23.3%) pregnant women (38 (41.7%) from the department of Cauca, 10 (35.7%) from Guajira, 5 (31.2%) from Meta, 6 (27.2%) from Amazonas and 10 (13.8%) from Córdoba). Iodine deficiency (<100 µg/L) was observed in 42 (14.9%) pregnant women (16 (11.6%) mild (50-99 µg/L), 19 (13.8%) moderate (20-49 µg/L) and 7 (5.1%) severe (<20 µg/L)). Being literate was a protective factor for iodine deficiency (odds ratio (OR)=0.19, 95% confidence interval (CI) 0.04-0.84, p=0.016). Being illiterate and iodine deficient was only a risk factor for goiter (OR=6.72, 95%CI 3.9-9.5, p=0.038) in the department of Cauca.
Conclusion:
A high prevalence of goiter, iodine deficiency and intrauterine growth restriction was observed in minority ethnic groups of Colombia. The highest prevalence and risk was observed in the department of Cauca.
BACKGROUND
Vascular risk factors, particularly hypertension, are important contributors to accelerated brain aging. We sought to quantify vascular risk factor risks over adulthood and assess the empirical evidence for risk thresholds.
METHODS
We used SBP (systolic blood pressure) and diastolic blood pressure, total cholesterol, fasting blood glucose, and body mass index measurements collected from participants in the CARDIA study (Coronary Artery Risk Development in Young Adults) at 2- to 5-year intervals through year 30. The Montreal Cognitive Assessment and domain-specific cognitive tests were performed at year 30. White matter hyperintensity volume was measured by magnetic resonance imaging. We used a 2-step method to fit longitudinal vascular risk factor exposures to optimized spline functions with mixed-effects models, then used the participant-specific random effects that characterized individual exposures over time in cross-sectional models adjusted for sex, race, age, and education to study effects on midlife brain health.
RESULTS
Change in SBP up to 33 years of age was negatively associated with Montreal Cognitive Assessment scores (−0.29 Montreal Cognitive Assessment Z score per mm Hg/y change [95% CI, −0.49 to −0.09]; P =0.005), with similar effects for SBP changes from 33 to 49 years of age (−0.08 [95% CI, −0.16 to 0.01]; P =0.08). We observed comparable, significant associations between SBP exposure during those ages, midlife performance on specific cognitive domains, and volume of white matter hyperintensity (all P <0.05). SBP ≤111 mm Hg was the estimated threshold below which no harmful association with midlife cognitive performance was identified.
CONCLUSIONS
SBP in early adulthood is the vascular risk factor most strongly associated with midlife cognitive performance and white matter hyperintensity burden, with SBP 111 mm Hg suggested as a harm threshold.
Background
Iodine nutrition is critical for fetal neurodevelopment in the first trimester of pregnancy, a period associated with dramatic changes in thyroid function. The aim of this study was to evaluate iodine nutritional status and thyroid function reference ranges in the first trimester in Taiwan.
Methods
Pregnant women aged 20 years and above in the first trimester were recruited in Taipei Veterans General Hospital, Taiwan from March 2019 to July 2022. Each participant provided a spot urine sample for measurement of urinary iodine concentration (UIC) and a blood sample for check-up of thyroid function and thyroid autoantibodies. A simple food frequency questionnaire was also completed.
Results
A total of 209 women with a mean age of 32.9 ± 4.4 years were enrolled. The median UIC was 160.9 μg/L [interquartile range (IQR): 105.0-246.2 μg/L], indicating overall iodine sufficiency. The gestational thyroid function reference ranges were: TSH [median: 0.93 (0.007-2.9) µIU/mL], free T4 [1.3 (0.93-2.2) ng/dL], free T3 [3.0 (2.3-5.0) ng/dL], total T4 [9.9 (6.4-16.9) ng/dL] and total T3 [135 (88-231) ng/dL]. If the non-pregnant reference range of serum TSH was used, eight women (4.8%) would be misclassified as having subclinical hyperthyroidism, and two women (1.2%) with subclinical hypothyroidism would be missed. In multivariate analysis, nulliparous [adjusted odds ratio (OR) from model 1-3: 2.02, 2.05, 2.02; 95% confidence interval (CI): 1.08-3.77, 1.10-3.81, 1.11-3.66; p = 0.027, 0.023, 0.022, respectively] and multivitamin non-users (adjusted OR from model 1-3: 1.86, 1.85, 1.78; 95% CI: 1.04-3.34, 1.03-3.32, 1.004-3.71; p = 0.038, 0.039, 0.049, respectively) had increased odds of having lower UIC levels <150 μg/L.
Conclusion
The iodine nutritional status in the first trimester is adequate in Taiwan; however, certain subgroups such as nulliparous and multivitamin non-users are still at risk for iodine deficiency. Gestational thyroid function reference ranges are needed for correct diagnosis of thyroid dysfunction in pregnancy.
Background
Growing the human brain requires all necessary nutrients to form and maintain, so the development of cognitive functions of infants and children depends on adequate nutrition. Children whose mothers had inadequate nutrition are at high risk for cognitive dysfunction. The objective of the present study was to review the studies conducted on “the relationship between nutrient intake during pregnancy and the development of cognitive functions in toddlers”. The present study was conducted by systematic review method using PRISMA checklist items.
Methods
To conduct this study, the keywords “maternal nutrition”, “pregnancy diet”, “pregnancy supplement”, “IQ”, “intelligence quotient”, “neurodevelopment”, “cognitive function”, “toddler”, “early years” and “infant” were searched based on the Mesh database in scientific databases including Scopus, SID, Google Scholar, PubMed, and Science Direct to find articles related to the effect of nutrition during pregnancy on the development of the cognitive function of toddlers and its components in Persian and English. Finally, 17 articles were selected for review in this study.
Results
The results showed that taking a supplement of iron, saturated fatty acids, vitamins B and D, and folic acid improved the cognitive functions of toddlers. On the other hand, taking supplements containing iodine and zinc had no significant effect on the development of cognitive functions. Diets containing seafood during pregnancy had a beneficial effect on the cognitive functions of children.
Conclusions
The study results highlighted the importance of adequate nutrition during pregnancy and showed that maternal nutrition played an important role in the development of cognitive functions of toddlers.
Iodine is an essential micronutrient required for thyroid hormone synthesis. The iodine requirement increases during pregnancy and its deficiency is associated with major adverse outcomes like pregnancy loss, infant death, neonatal hypothyroidism, cretinism, and psychomotor retardation. Iodine deficiency disorders are the most common preventable cause of brain damage. Successful implementation of salt iodization programs over the last two decades has changed the spectrum of deficiency from severe to mild/moderate. In this chapter, we will review the impact of iodine deficiency on feto-maternal and neonatal outcomes. The definition of iodine deficiency, epidemiology, and current recommendations to prevent iodine deficiency in pregnancy and postpartum will also be reviewed.
Objectives:
Understanding iodine deficiency (ID) burdens and trends in Asia can help guide effective intervention strategies. This study aims to report the incidence, prevalence, and disability-adjusted life years (DALYs) of ID in 48 Asian countries during the period 1990-2019.
Study design:
Data on ID were retrieved from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 and estimated by age, sex, geographical region, and sociodemographic index (SDI).
Methods:
The estimated annual percentage change (EAPC) was calculated to evaluate the changing trend of age-standardized incidence rate (ASIR), age-standardized prevalence rate (ASPR), and age-standardized DALYs rate (ASDR) related to ID during the period 1990-2019.
Results:
In Asia, there were 126,983,965.8 cases with 5,466,213.1 new incidence and 1,765,995.5 DALYs of ID in 2019. Between 1999 and 2019, the EAPC in ASIR, ASPR and ASDR were -0.6 (95% confidence interval [CI], -0.8 to -0.4), -0.9 (95% CI, -1.2 to -0.7), and -1.6 (95% CI, -1.8 to -1.5), respectively. Malaysia charted the largest decrease in ASIR, ASPR, and ASDR (82.4%, 85.3%, and 80.9% separately), whereas the Philippines and Pakistan were the only two countries that witnessed an increase in ASIR and ASPR. ID burdens were more pronounced in women, countries located to the south of the Himalayas, and low-middle SDI regions.
Conclusions:
The incidence, prevalence, and DALYs of ID in Asia substantially decreased from 1990 to 2019. Women and low-middle SDI countries have relatively high ID burdens. Governments need to pay constant attention to the implementation and monitoring of universal salt iodization.
Iodine is ingested in several chemical forms. Iodine is rapidly and nearly all absorbed (>90%) in the stomach and duodenum. Iodate, widely used in iodization of salt, is reduced in the gut and absorbed as iodide. The body of a healthy adult contains 15–20 mg of iodine, of which 70–80% is in the thyroid. Iodine is used by the thyroid gland to produce thyroid hormones. For women, iodine is necessary for optimal function of the reproductive system and for normal fetal growth and development. In chronic iodine deficiency, the iodine content of the thyroid might fall to less than 20 microgram. In iodine-sufficient areas, the adult thyroid traps about 60 microgram of iodine per day to balance losses and maintain synthesis of thyroid hormone. The sodium/iodide symporter (NIS) transfers iodine intake; in situations with adequate iodine supply, 10% or less of absorbed iodine is taken up by the thyroid. In chronic iodine deficiency, this percentage can exceed 80%. Iodine consists of 65% and 59% of the weights of thyroxine (T4) and tri-iodothyronine (T3), respectively. The released iodine enters the plasma iodine pool and can be taken up again by the thyroid or excreted by the kidney. More than 90% of ingested iodine is ultimately excreted in the urin. Despite significant progress has been achieved in elimination of iodine deficiency worldwide, vulnerable groups such as pregnant women, lactating mothers, and infants are still at risk of iodine deficiency. During pregnancy several major changes occur in thyroid physiology that result in higher iodine requirements in pregnant than non-pregnant women, which can be difficult to meet through diet; therefore, iodine supplementation for pregnant and those who are planning for pregnancy is necessary. The most serious adverse effect of iodine deficiency occurs to the fetus. It is well documented that severe iodine deficiency in utero and in early life can result in impaired mental function, poor school performance, and reduced intellectual ability. However, it is still uncertain whether mild-to-moderate maternal iodine deficiency may have a long-term negative impact on child neurodevelopment. Few studies to date have explored the effect of iodine excess on maternal and fetal outcomes. It has been shown that chronic excess iodine intake during pregnancy was associated with maternal hypothyroxinemia, which has been linked with preterm delivery and possibly irreversible childhood intelligence quotient. This chapter deals with the role of iodine and its metabolism during pregnancy. The most recent data on number of countries according to their iodine status in the general population as well as pregnant women are here reported. In addition, consequences of iodine deficiency and excess in pregnant women and fetuses and potential benefits of iodine supplementation in this critical period are discussed.
Iodine is an important micronutrient that is required for the production of thyroid hormone. The most vulnerable groups of inadequate iodine status are pregnant and lactating women and their developing fetuses and neonates, due to the crucial role of normal thyroid function during early growth. Higher amounts of iodine are required during pregnancy and lactation due to the increased physiologic requirements of thyroid hormone production during these periods. Across the life span, iodine deficiency disorders resulting from inadequate production of thyroid hormones include mental impairment, hypothyroidism, goiter, cretinism, and varying degrees of other growth and development abnormalities. This review highlights the sources of iodine, role of iodine in thyroid physiology, measurement tools of assessing iodine status, the consequences of iodine deficiency and excess, and evidence to date of iodine supplementation in pregnant women.KeywordsIodinePotassium iodidePregnancyThyroidPreconceptionNeurocognition
Iodine is an essential micronutrient as it is a key element in the synthesis of thyroid hormones and mediates the effects of thyroid hormone on the brain. Iodine deficiency is a public health problem affecting the whole lifespan which children, pregnant, and lactating women are the most vulnerable categories. Iodine is crucial for maternal health and for development of various aspects of intellectual ability of the offspring. Among young children, deficit in iodine has been demonstrated to affect cognitive ability and school performance. Some mechanisms have been postulated on how iodine could impact the brain with genetic expression being the starting point. Various brain structures and systems (i.e., the hippocampus, myeline, and neurotransmitters) are involved and affected with iodine deficiency. Nevertheless, inconsistencies and gaps in the exact mechanism still exist on how iodine could impact the brain. This chapter discusses the current findings on effect of iodine on brain function across the lifespan and the various possible mechanisms of action and interaction of iodine, thyroid hormone, and the brain.KeywordsIodineIodine deficiencyIodine supplementationHyroid hormonesBrainDevelopment
Сегодня миллионы детей в возрасте до 5 лет не достигают своего потенциала развития. Развитие нейробиологии показало, что здоровье и благополучие во взрослом возрасте основаны на факторах развития, которые воздействуют на ребенка в раннем детстве. Дети, которые полноценно питаются, имеют больше возможностей для раннего когнитивного развития и с большей вероятностью добьются успеха. Адекватное, соответствующее возрасту, богатое микроэлементами питание в младенчестве и детстве имеет решающее значение для оптимального развития и функционирования мозга, поскольку оно обеспечивает процессы нейрогенеза, роста аксонов и дендритов, синаптогенеза, гибели клеток, синаптического прунинга, миелинизации и глиогенеза. Несмотря на неоспоримое преимущество грудного вскармливания для правильного и своевременного когнитивного развития ребенка и тот факт, что в Восточной Европе, по данным Всемирной организации здравоохранения (ВОЗ), около 80–90% женщин начинают кормить грудью в родильном отделении учреждения здравоохранения, грудное вскармливание до полугода могут сохранить только 40% матерей. В то же время детям, не находящимся на грудном вскармливании, необходимо восполнять дефицит макро- и микронутриентов, а также других необходимых веществ, которые содержатся только в грудном молоке и не обеспечиваются или часто получаются в недостаточном количестве при использовании заменителей. В данном обзоре обсуждается значение некоторых макро- и микроэлементов для развития центральной нервной системы, а также их эффективность и биодоступность в сочетании с молочными основами различного происхождения. Кроме того, авторы демонстрируют преимущества козьего молока в детском питании.
Today, millions of children under the age of 5 do not reach their developmental potential. Advances in neuroscience showed that health and well-being in adulthood are based on the developmental conditions in early childhood. Young children who are well-nourished have more opportunities for early cognitive development and are more likely to succeed. Adequate, age-appropriate, micronutrient-rich nutrition during infancy and childhood is critical for optimal brain development and function as it supports the processes of neurogenesis, axonal and dendritic growth, synaptogenesis, cell death, synaptic pruning, myelination, and gliogenesis. Despite the indisputable advantage of breastfeeding for the proper and timely cognitive development of the child and the fact that in Eastern Europe, according to the World Health Organization (WHO), about 80–90% of women start to breastfeed in the maternity ward of a health care institution, breastfeeding can be maintained by six months only by 40% of mothers. At the same time, children who are not breastfed need to compensate for the deficiency of macro- and micronutrients, as well as other essential substances that are found only in breast milk and are not supplied or often received in insufficient quantities with its substitutes. This review examines the importance of some macro- and microelements for the development of the central nervous system, as well as their efficacy and bioavailability in combination with milk bases of various origins, demonstrating the benefits of goat milk in baby food.
This chapter focuses on the source, pathways, exposure routes, benefits, and biosynthesis of iodine and its health consequences. Iodine is a heavy, greyish-black crystalline solid with a characteristic shinning metallic property. Iodine plays a vital role in human, plant, and animal life. Apart from its use in curing thyroid dysfunction, iodine in its liquid or solid form is also useful in many ways for scientific purposes such as disinfectant in water treatment, cleaning products for household, and base antiseptics in wound cleaning and for sterilizing skin for surgical procedures.
Malnutrition and micronutrient deficiencies are significant public health problems in the Central Asian country of Tajikistan, with over 26% of children under age 5 being stunted and 30% being anemic. The Khatlon Province is the country’s largest agricultural area where people are often dependent on home gardens to ensure food security. The proximity of households to resources such as markets, roads, and infrastructure can affect food availability, diets, and diversity of agricultural products for consumption. This study aims to evaluate whether the remoteness of a household affects the production, consumption, and acquisition of specific crops among households in Khatlon Province, Tajikistan. A remote household was defined as one that is distant from markets and the main center of population, difficult to travel to, and has limited resources. This cross-sectional study used a household survey and focus groups to measure crop production, consumption, and food acquisition. Household surveys were administered to 107 households in six Khatlon districts and 15 focus groups were conducted in various rural villages within Khatlon. Data was analyzed using a two-sample t-test for the household surveys and NVivo software for capturing major themes within the focus groups. Results revealed that there was no statistically significant difference when comparing households for remoteness in regard to crop production, frequency of consumption, and acquisition. Frequency of food consumption was similar when comparing remoteness but significantly decreased among all households when the crop was not in season. Programs that increase agricultural knowledge about production and extended growing season are extremely beneficial to improve nutrition in these vulnerable households. Additionally, gender-related concerns were discovered within the qualitative data such as the double burden of working to maintain crops as well as managing a household. Therefore, interventions based around agricultural production and acquisition should target women.
La petite enfance est la période la plus importante pour le développement humain. Cependant, les pays ont tendance à sous-investir dans cette phase de développement, en particulier au Moyen-Orient et en Afrique du Nord (MENA). Les enfants sont confrontés à des opportunités inégales de se développer en raison des circonstances de leur naissance. Cette recherche analyse les inégalités de chances dans le développement de la petite enfance dans trois pays du sud de la Méditerranée (Algérie, Maroc et Tunisie) ainsi que dans trois pays d’Europe orientale non membres de l’Union Européenne (UE) (Bosnie, Serbie et Ukraine). Les résultats démontrent qu’il existe une inégalité substantielle des chances dès le début de la vie. Diverses circonstances influent sur les inégalités précoces, notamment le niveau de vie du ménage, l’éducation de la mère et les différences géographiques.
Iodine intake is essential for the production of thyroid hormone. Iodine deficiency remains a public health problem in many regions around the world. Iodine deficiency can present as a spectrum of disorders depending on the degree of severity. Pregnant and lactating women are particularly vulnerable to iodine deficiency disorders because of their increased iodine requirements. Severe maternal iodine deficiency has been associated with cretinism or impaired neurodevelopment in children as well as obstetric complications. Universal salt iodization has been shown to prevent these disorders in severely iodine deficient areas. Recently, observational studies have demonstrated an association between mild-to-moderate iodine deficiency and poorer cognitive outcomes in children. In this review, we describe the iodine requirements for pregnant and lactating women, how population iodine status can be assessed, the effects of maternal iodine deficiency and excess, and current data regarding efficacy of iodine supplementation for women who are pregnant or lactating.
Objective
The monitoring of the populations’ iodine status is an essential part of successful programmes of iodine deficiency elimination. The current study aimed at the evaluation of current iodine nutrition in school children, pregnant and lactating women as a marker of the effectiveness and sustainability of mandatory iodine prophylaxis in Poland.
Design
The following iodine nutrition indicators were used: urinary iodine concentration (UIC) (all participants) and serum thyroglobulin (pregnant and lactating women).
Setting
The study was conducted in 2017 within the National Health Programme in five regions of Poland.
Participants
The research included 300 pregnant women, 100 lactating women and 1000 school children (aged 6–12 years).
Results
In pregnant women, median UIC was 111·6 µg/l; there was no significant difference in median UIC according to the region of residence. In 8 % of pregnant women, thyroglobulin level was >40 ng/ml (median thyroglobulin 13·3 ng/ml). In lactating women, median UIC was 68·0 µg/l. A significant inter-regional difference was noted ( P = 0·0143). In 18 % of breastfeeding women, thyroglobulin level was >40 ng/ml (median thyroglobulin 18·5 ng/ml). According to the WHO criteria, the investigated sample of pregnant and lactating women was iodine-deficient. Median UIC in school children was 119·8 µg/l (with significant inter-regional variation; P = 0·0000), which is consistent with iodine sufficiency. Ninety-four children (9·4 %) had UIC < 50 µg/l.
Conclusions
Mandatory iodisation of household salt in Poland has led to a sustainable optimisation of iodine status in the general population. However, it has failed to assure adequate iodine nutrition during pregnancy and lactation.
Background:
The Quality of Reporting of Meta-analyses (QUOROM) conference was convened to address standards for improving the quality of reporting of meta-analyses of clinical randomised controlled trials (RCTs).
Methods:
The QUOROM group consisted of 30 clinical epidemiologists, clinicians, statisticians, editors, and researchers. In conference, the group was asked to identify items they thought should be included in a checklist of standards. Whenever possible, checklist items were guided by research evidence suggesting that failure to adhere to the item proposed could lead to biased results. A modified Delphi technique was used in assessing candidate items.
Findings:
The conference resulted in the QUOROM statement, a checklist, and a flow diagram. The checklist describes our preferred way to present the abstract, introduction, methods, results, and discussion sections of a report of a meta-analysis. It is organised into 21 headings and subheadings regarding searches, selection, validity assessment, data abstraction, study characteristics, and quantitative data synthesis, and in the results with "trial flow", study characteristics, and quantitative data synthesis; research documentation was identified for eight of the 18 items. The flow diagram provides information about both the numbers of RCTs identified, included, and excluded and the reasons for exclusion of trials.
Interpretation:
We hope this report will generate further thought about ways to improve the quality of reports of meta-analyses of RCTs and that interested readers, reviewers, researchers, and editors will use the QUOROM statement and generate ideas for its improvement.
Titania-supported Au catalysts were given both low temperature reduction and high temperature reduction at 473 and 773 K, respectively, and their adsorption and catalytic properties were compared to identically pretreated Pt/TiO2 catalysts and pure TiO2 samples as well as Au/SiO2 catalysts. This was done to determine whether a reaction model proposed for methanol synthesis over metals dispersed on Zn, Sr and Th oxides could also explain the high activities observed in hydrogenation reactions over MSI (Metal-Support Interaction) catalysts such as Pt/TiO2. This model invokes O vacancies on the oxide support surface, formed by electron transfer from the oxide to the metal across Schottky junctions established at the metal-support interface, as the active sites in this reaction. The similar work functions of Pt and Au should establish similar vacancy concentrations, and O2 chemisorption indicated their presence. However, these Au catalysts were completely inactive for CO and acetone hydrogenation, and ethylene hydrogenation rates were lower on the supported Au catalysts than on the supports alone. Consequently, this model cannot explain the high rate of the two former reactions over TiO2-supported Pt although it does not contradict models invoking specialinterfacial sites.
The lateral mobility of membrane lipids and proteins is presumed to play an important functional role in biomembranes. Photobleaching studies have shown that many proteins in the plasma membrane have diffusion coefficients at least an order of magnitude lower than those obtained when the same proteins are reconstituted in artificial bilayer membranes. Depending on the protein, it has been shown that either the cytoplasmic domain or the ectodomain is the key determinant of its lateral mobility. Single particle tracking microscopy, which allows the motions of single or small groups of membrane molecules to be followed, promises not only to reveal new features of membrane dynamics, but also to help explain longstanding puzzles presented by the photobleaching studies, particularly the so-called immobile fraction. The combination of the two complementary technologies should measurably enhance our understanding of membrane microstructure.
The view is widely held that experimental methods (randomised controlled trials) are the "gold standard" for evaluation and that observational methods (cohort and case control studies) have little or no value. This ignores the limitations of randomised trials, which may prove unnecessary, inappropriate, impossible, or inadequate. Many of the problems of conducting randomised trials could often, in theory, be overcome, but the practical implications for researchers and funding bodies mean that this is often not possible. The false conflict between those who advocate randomised trials in all situations and those who believe observational data provide sufficient evidence needs to be replaced with mutual recognition of the complementary roles of the two approaches. Researchers should be united in their quest for scientific rigour in evaluation, regardless of the method used.
In previous articles we have focused on the potentials, principles, and pitfalls of meta-analysis of randomised controlled trials.1 2 3 4 5 Meta-analysis of observational data is, however, also becoming common. In a Medline search we identified 566 articles (excluding those published as letters) published in 1995 and indexed with the medical subject heading (MeSH) term “meta-analysis.” We randomly selected 100 of these articles and examined them further. Sixty articles reported on actual meta-analyses, and 40 were methodological papers, editorials, and traditional reviews (1). Among the meta-analyses, about half were based on observational studies, mainly cohort and case-control studies of medical interventions or aetiological associations.
View this table:
Characteristics of 100 articles randomly selected from articles published in 1995 and indexed in Medline with keyword “meta-analysis”
The randomised controlled trial is the principal research design in the evaluation of medical interventions. However, aetiological hypotheses—for example, those relating common exposures to the occurrence of disease—cannot generally be tested in randomised experiments. Does breathing other people's tobacco smoke cause lung cancer, drinking coffee cause coronary heart disease, and eating a diet rich in saturated fat cause breast cancer? Studies of such “menaces of daily life”6 use observational designs or examine the presumed biological mechanisms in the laboratory. In these situations the risks involved are generally small, but once a large proportion of the population is exposed, the potential public health implications of these associations—if they are causal—can be striking.
Analyses of observational data also have a role in medical effectiveness research.7 The evidence available from clinical trials will rarely answer all the important questions. Most trials are conducted to establish efficacy and safety of a single agent in a specific clinical situation. Owing to the limited size of such trials, less common adverse effects of drugs may only be detected in case-control …
As part of its nationwide campaign to eliminate iodine deficiency disorders in China by the end of the year 2000, the government has announced the opening of the National Iodine Deficiency Disorders Reference Laboratory. The laboratory will provide the 31 provincial laboratories and hundreds of local facilities in China with reliable reference standards and quality control indicators to help address the problem. Additionally, the laboratory would also be tasked to develop nationwide training programs, teaching materials and report to the Chinese Ministry of Health on the progress of the campaign against iodine deficiency. National Iodine Deficiency Disorders Reference Library director Li Sumei admits that there are many problems associated with local-level laboratories due to the low quality of technicians and the fact that they receive less training. The incidence of iodine deficiency among children aged 8-10 years, according to Li, has decreased from 20% in 1995 to less than 10% in 1999 as a result of governmental campaigns against the disease. Iodine deficiency can cause hypothyroidism, complications during pregnancy, and cretinism in infants and is considered as a factor in more than 90% of the 11 million cases of mental disability.
Several recent publications have drawn attention to the role of the thyroid hormone status of the mother on the future neuropsychological development of the child. The screening of pregnant women for clinical or subclinical hypothyroidism based on second trimester elevated maternal TSH values has been proposed. Here, we have summarized present epidemiological and experimental evidence strongly suggesting that conditions resulting in first trimester hypothyroxinemia (a low for gestational age circulating maternal free T4, whether or not TSH is increased) pose an increased risk for poor neuropsychological development of the fetus. This would be a consequence of decreased availability of maternal T4 to the developing brain, its only source of thyroid hormone during the first trimester; T4 is the required substrate for the ontogenically regulated generation of T3 in the amounts needed for optimal development in different brain structures, both temporally and spatially. Normal maternal T3 concentrations do not seem to prevent the potential damage of a low supply of T4, although they might prevent an increase in circulating TSH and detection of the hypothyroxinemia if only TSH is measured. Hypothyroxinemia seems to be much more frequent in pregnant women than either clinical or subclinical hypothyroidism and autoimmune thyroid disease, especially in regions where the iodine intake of the pregnant woman is inadequate to meet her increased needs for T4. It is proposed that the screening of pregnant women for thyroid disorders should include the determination of free T4 as soon as possible during the first trimester as a major test, because hypothyroxinemia has been related to poor developmental outcome, irrespective of the presence of high titers of thyroid autoantibodies or elevated serum TSH. The frequency with which this may occur is probably 150 times or more that of congenital hypothyroidism, for which successful screening programs have been instituted in many countries.
Growth and development of 207 children (49% males; mean age 5.4 years [SD 0.2], range 4 to 7.3 years whose mothers received iodine during pregnancy, and children who received iodine first in their 2nd year, were examined in 1996; 192 children (49% males; mean age 6.5 years [SD 0.2], range 5.8 to 6.9 years) whose mothers received iodine while pregnant were seen in 1998. Children were from the southern part of China's Xinjiang Province which has the lowest levels of iodine in water and soil ever recorded. Head circumference but not height was improved for those who received iodine during pregnancy (compared with those receiving iodine at age 2) and for those supplemented before the end of the 2nd trimester (relative to those supplemented during the 3rd trimester). Iodine before the 3rd trimester predicted higher psychomotor test scores for children relative to those provided iodine later in pregnancy or at 2 years. Results from the test for cognitive development resulted in trend only differences between those children supplemented during pregnancy versus later. The results address the question of when maternal iodine supplements should begin in public health programs world wide. Findings may be relevant to the treatment of maternal and newborn thyroid deficiency in industrialized countries, particularly for those infants delivered before the end of the second trimester.
Since 1980 s', numerous studies on intelligence quotient (IQ) have documented, in the areas prevalent with severe, moderate and even mild iodine deficiency, which is a risk factor for retardation in mental development there. It was purposed for this paper to quantify the relationship between iodine deficiency and mental development in children and to explore the etiological role of iodine deficiency in mental retardation and the protective effects on children's intelligence of iodine supplementation.
A total of 59 independent investigations published during 1980 and 1998 were selected for meta-analysis, including 20 studies on intelligence determined by Raven's Test and 39 by China Benit Scale.
Homogeneity test showed that there was no significant difference in baseline features between two groups (P > 0.05). The hypothesis testing showed that the homogeneity of each study group was obviously statistically significant (P > 0.05). The results demonstrated that IQ in children at risk for iodine deficiency showed a marked drop by 8.94 points with Raven's Test and by 10.80 points with China Binet Scale, respectively, with an average drop of 10 points. Substantial evidence now available has showed that mental retardation can be prevented by effective correction of iodine deficiency through iodine supplement either iodized salt or iodized oil, which is confirmed by an obvious increase in 11.5 points of IQ in average, and in 11.85 by Raven's Test and 11.64 by China Binet Scale, respectively.
Iodine nutrition plays an important and positive role in brain development. Iodine deficiency leads to loss of 10 points of IQ and 11.5 points can be gained for children in the iodine deficiency areas after significant iodine supplement.
To estimate the role and extent of iodine deficiency, iodine supplement and iodine excess on mental development of children.
Meta-analysis was applied to study 128 independent items from 63 published and non-published papers and reports. The standards of references collected included: age of sample declared by references was 5 - 15; belong to comparison study; children lived in iodine deficiency disorders (IDD) and iodine excess areas; no difference of social economic and culture development level between the study group and the control group.
Sixty-seven percent and 79% of the reports mainly involved severe IDD areas respectively. Hunter test of each studies, i.e. iodine deficiency, iodine supplement and excessive iodine group had not discovered statistic difference at the level of alpha = 0.05. The weighted average ES of damage affecting on children's intelligence by iodine deficiency achieved 0.69, which was equivalent to a marked drop in 10.4 IQ points [95% confidence interval (CI): 9.9 - 10.9] when comparing with the children living under non-IDD. The weighted average ES of protective effect on children's intelligence by iodine supplement reached 0.81, which meant that the IQ of children born after correction of iodine deficiency increased 12.2 points (95% CI: 11.5 - 12.9) in comparison with those born at least one year before the correction of iodine deficiency. Most of the references about the relationship between iodine excess and intelligence were gathered from proceedings, while the others were from journals. They location were in some areas of Shandong, Hebei, Shanxi and Inner Mongolia. The mean ES of the role of iodine excess on intelligence was 0.21, which was corresponding to 3.2 IQ points (95% CI: 2.5 - 4.0).
1) Iodine deficiency played a role of intermediate strength compared with other causes in delaying brain development making children to be at least 10 IQ points loss in IDD areas. 2) Effective iodine supplement plays a remarkable strengthening role in promoting brain development and can cause 12 IQ points increase for children who were born after the correction of iodine status. 3) Iodine excess has not shown significant important role in children's intelligence.
The relationship of a low-Iodine and high-fluoride environment to subclinical cretinism in Xinjiang
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