Iodine supplementation in pregnancy and its effect on child cognition

Melse‐Boonstra, Alida; Gowachirapant, Sueppong; Jaiswal, Nidhi; Winichagoon, Pattanee; Srinivasan, Krishnamachari; Zimmermann, Michael

doi:10.1016/j.jtemb.2012.03.005

Cited by 29 publications

(20 citation statements)

References 27 publications

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“…Large scale controlled trials are now needed to clarify whether gestational supplementation will benefit infant neurodevelopment in countries with marginal iodine deficiency. One such trial is currently in progress in India and Thailand and aims to recruit 800 women randomised to receive 200 mg of KI or placebo in early pregnancy (81). Outcomes will include infant neuropsychiatric function assessed at 12-18 months amongst other indices of thyroid and developmental function.…”

Section: Resultsmentioning

confidence: 99%

THERAPY OF ENDOCRINE DISEASE: Impact of iodine supplementation in mild-to-moderate iodine deficiency: systematic review and meta-analysis

Taylor

Okosieme

Dayan

et al. 2014

European Journal of Endocrinology

135

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Background: Although the detrimental effects of severe iodine deficiency are well recognised, the benefits of correcting mild-to-moderate iodine deficiency are uncertain. Objectives: We undertook a systematic review of the impact of iodine supplementation in populations with mildto-moderate iodine deficiency. Methods: We searched Medline and the Cochrane library for relevant articles published between January 1966 and April 2013, which investigated the effect of iodine supplementation on maternal and newborn thyroid function, infant neurodevelopment and cognitive performance in school-age children. The quality of studies was graded and eligible trials were evaluated in the meta-analysis. Results: Nine randomised controlled trials (RCTs) and eight observational studies met the inclusion criteria. Controlled trials on infant neurodevelopment were lacking; gestational iodine supplementation reduced maternal thyroid volume and serum thyroglobulin and in some studies prevented a rise in serum thyroid-stimulating hormone. None of the intervention trials recorded an excess frequency of thyroid dysfunction in contrast to observational studies. A pooled analysis of two RCTs which measured cognitive function in school-age children showed modest benefits of iodine supplementation on perceptual reasoning (standardised mean difference (SMD) 0.55; 95% CI 0.05, 1.04; PZ0.03) and global cognitive index (SMD 0.27; 95% CI 0.10, 0.44; PZ0.002) with significant heterogeneity between studies. Conclusion: Iodine supplementation improves some maternal thyroid indices and may benefit aspects of cognitive function in school-age children, even in marginally iodine-deficient areas. Further large prospective controlled studies are urgently required to clarify these findings and quantify the risk/benefits of iodine supplementation in regions previously believed to be iodine sufficient such as the UK.

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Section: Resultsmentioning

confidence: 99%

THERAPY OF ENDOCRINE DISEASE: Impact of iodine supplementation in mild-to-moderate iodine deficiency: systematic review and meta-analysis

Taylor

Okosieme

Dayan

et al. 2014

European Journal of Endocrinology

135

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“…The outcomes of these trials will provide the evidence base for iodine supplementation of pregnant women living in areas of iodine deficiency. [26] However, after iodine supplementation programme, thyroid autoimmunity has been considered as an important cause for persistence of goiter and it is believed that auto immunity has increased following salt iodization. [2728]…”

Section: Discussionmentioning

confidence: 99%

Prevalence of iodine deficiency among pregnant and lactating women: Experience in Kolkata

Majumder

Jaiswal

Chatterjee

2014

Indian J Endocr Metab

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Objective:The cross-sectional study was carried out to assess the iodine status of pregnant and lactating mothers, using median urinary iodine excretion (UIE) as the measure of outcome, to document the prevalence of iodine deficiency.Materials and Methods:The present study assessed the UIE in the morning urine samples from 237 pregnant women, 73 lactating mothers and 59 healthy non-pregnant female controls.Results:Out of 237 pregnant women, 88 (37%) exhibited insufficient iodine nutrition (UIE < 150 μg/l), out of 73 lactating mothers, 24 (33%) exhibited insufficient iodine nutrition (UIE < 100 μg/l) and only 3% female control subjects exhibited insufficient iodine nutrition (UIE < 100μg/l). Additionally, a number (32.3%) of babies born of iodine deficient mothers had respiratory distress at birth.Conclusion:It appears that the present salt iodination program is adequate for the general population but insufficient for the pregnant and lactating mothers. They need to be targeted with iodine supplements throughout pregnancy and lactation. Increased incidence of respiratory distress in the new born of iodine deficient mothers merits further study.

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“…[1] Since iodine is important for synthesis of thyroid hormones which in turn play a major role in the neurodevelopment of fetus from early pregnancy onward, the iodine nutrition of pregnant women has assumed importance especially in endemic areas. [1112] The iodine requirements during pregnancy increase since there is an increment in thyroid hormone synthesis to provide for the needs of the fetus, and there is an increased loss of iodine in the urine resulting from an increased renal clearance during pregnancy. UIE is presently the most practical biomarker for assessing iodine nutrition in a population, although not in individuals since it reflects recent iodine intake.…”

Section: Discussionmentioning

confidence: 99%

“…However, recent findings suggest that hypothyroxinemia can negatively affect child health outcomes, including neonatal behavior and infant cognitive functioning. [111213] As it is clear that thyroid hormones are essential for neurodevelopment from early pregnancy onward, data are scarce from populations that have been previously iodine deficient (ID) and have now achieved sufficiency, like in India. [141516171819] There are no reports on the iodine status of the pregnant women and its effect on the neonatal thyroid function from Kashmir valley of North India, part of sub-Himalayan belt, considered to be endemic region for IDD two decades before.…”

Section: Introductionmentioning

confidence: 99%

Universal salt iodization is successful in Kashmiri population as iodine deficiency no longer exists in pregnant mothers and their neonates: Data from a tertiary care hospital in North India

Charoo

Sofi

Nisar

et al. 2013

Indian J Endocr Metab

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Introduction:Normal pregnancy results in a number of important physiological and hormonal changes that alter thyroid function. In pregnancy, the thyroid gland being subjected to physiological stress undergoes several adaptations to maintain sufficient output of thyroid hormones for both mother and fetus. Consequently, pregnant women have been found to be particularly vulnerable to iodine deficiency disorders (IDD), and compromised iodine status during pregnancy has been found to affect the thyroid function and cognition in the neonates.Objectives:Two decades after successful universal salt iodization (USI) in the country, there is scarce data on the iodine status of the pregnant women and their neonates. This is more relevant in areas like Kashmir valley part of sub-Himalayan belt, an endemic region for IDD in the past. The objective was to estimate Urinary Iodine status in pregnant women, the most vulnerable population.Materials and Methods:We studied thyroid function [free T3 (FT3), T3, free T4 (FT4), T4, thyroid stimulating hormone (TSH)] and urinary iodine excretion (UIE) in the 1st, 2nd, and 3rd trimesters and at early neonatal period in neonates in 81 mother–infant pairs (hypothyroid women on replacement) and compared them with 51 control mother–infant pairs (euthyroid).Results:Mean age of cases (29.42 + 3.56 years) was comparable to that of controls (29.87 + 3.37 years). The thyroid function evaluation done at baseline revealed the following: FT3 2.92 ± 0.76 versus 3.71 ± 0.54 pg/ml, T3 1.38 ± 0.37 versus 1.70 ± 0.35 ng/dl, FT4 1.22 ± 0.33 versus 1.52 ± 0.21 ng/dl, T4 9.54 ± 2.34 versus 13.55 ± 2.16 μg/dl, and TSH 7.92 ± 2.88 versus 4.14 ± 1.06 μIU/ml in cases versus controls (P > 0.01), respectively. The 2nd to 6th day thyroid function of neonates born to case and control mothers revealed T3 of 1.46 ± 0.44 versus 1.48 ± 0.36 ng/dl, T4 of 12.92 ± 2.57 versus 11.76 ± 1.78 μg/dl, and TSH of 3.64 ± 1.92 versus 3.82 ± 1.45 μIU/ml, respectively.Discussion:UIE was similar (139.12 ± 20.75 vs. 143.78 ± 17.65 μg/l; P = 0.8), but TSH values were higher in cases (7.92 ± 2.88) as compared to controls (4.14 ± 1.06). Although UIE gradually declined from 1st trimester to term, it remained in the sufficient range in both cases and controls. Thyroid function and UIE was similar in both case and control neonates.Conclusion:We conclude that pregnant Kashmiri women and their neonates are iodine sufficient, indicating successful salt iodization in the community. Large community-based studies on thyroid function, autoimmunity, malignancies, etc., are needed to see the long-term impact of iodization.

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Iodine supplementation in pregnancy and its effect on child cognition

Cited by 29 publications

References 27 publications

THERAPY OF ENDOCRINE DISEASE: Impact of iodine supplementation in mild-to-moderate iodine deficiency: systematic review and meta-analysis

THERAPY OF ENDOCRINE DISEASE: Impact of iodine supplementation in mild-to-moderate iodine deficiency: systematic review and meta-analysis

Prevalence of iodine deficiency among pregnant and lactating women: Experience in Kolkata

Universal salt iodization is successful in Kashmiri population as iodine deficiency no longer exists in pregnant mothers and their neonates: Data from a tertiary care hospital in North India

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