Maternal iodine status in a multi-ethnic UK birth cohort: associations with child cognitive and educational development
Maternal iodine status in a multi-ethnic UK birth cohort: associations with child cognitive and educational development
Background: Maternal iodine requirements increase during pregnancy to supply thyroid hormones critical for fetal neurodevelopment. Iodine insufficiency may result in poorer cognitive or child educational outcomes but current evidence is sparse and inconsistent. Objectives: To quantify the association between maternal iodine status and child educational outcomes. Methods: Urinary iodine concentrations (UIC) and iodine/creatinine ratios (I:Cr) were measured in 6971 mothers at 26-28 weeks' gestation participating in the Born in Bradford cohort. Maternal iodine status was examined in relation to child school achievement (early years foundation stage (EYFS), phonics, and Key Stage 1 (KS1)), other learning outcomes, social and behavioural difficulties, and sensorimotor control in 5745 children aged 4-7 years. Results: Median (interquartile range) UIC was 76 µg/L (46, 120), and I:Cr was 83 µg/g (59, 121). Overall, there was no strong or consistent evidence to support associations between UIC or I:Cr and neurodevelopmental outcomes. For instance, predicted EYFS and phonics scores (primary outcomes) at the 25th vs 75th I:Cr percentiles (99% confidence intervals) were similar, with no evidence of associations: EYFS scores were 32 (99% CI 31, 33) and 33 (99% CI 32, 34), and phonics scores were 34 (99% CI 33, 35) and 35 (99% CI 34, 36), respectively. Conclusions: In the largest single study of its kind, there was little evidence of detrimental neurodevelopmental outcomes in children born to pregnant women with iodine insufficiency as defined by World Health Organization–outlined thresholds. Alternative functional biomarkers for iodine status in pregnancy and focused assessment of other health outcomes may provide additional insight.
born in Bradford, child development, cognition, deficiency, iodine, nutrition, pregnancy
Threapleton, Diane E.
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Snart, Charles Jonathan Peter
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Keeble, Claire
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Waterman, Amanda H.
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Taylor, Elizabeth
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Mason, Dan
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Reid, Stephen
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Azad, Rafaq
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Hill, Liam J.B.
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Meadows, Sarah
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McKillion, Amanda
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Alwan, Nisreen
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Cade, Janet E.
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Simpson, Nigel A.B.
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Stewart, Paul M.
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Zimmermann, Michael
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Wright, John
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Waiblinger, Dagmar
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Mon-Williams, Mark
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Hardie, Laura
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Greenwood, Darren
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Threapleton, Diane E.
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Snart, Charles Jonathan Peter
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Keeble, Claire
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Waterman, Amanda H.
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Taylor, Elizabeth
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Mason, Dan
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Reid, Stephen
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Azad, Rafaq
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Hill, Liam J.B.
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Meadows, Sarah
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McKillion, Amanda
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Alwan, Nisreen
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Cade, Janet E.
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Simpson, Nigel A.B.
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Stewart, Paul M.
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Zimmermann, Michael
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Wright, John
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Waiblinger, Dagmar
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Mon-Williams, Mark
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Hardie, Laura
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Greenwood, Darren
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Threapleton, Diane E., Snart, Charles Jonathan Peter, Keeble, Claire, Waterman, Amanda H., Taylor, Elizabeth, Mason, Dan, Reid, Stephen, Azad, Rafaq, Hill, Liam J.B., Meadows, Sarah, McKillion, Amanda, Alwan, Nisreen, Cade, Janet E., Simpson, Nigel A.B., Stewart, Paul M., Zimmermann, Michael, Wright, John, Waiblinger, Dagmar, Mon-Williams, Mark, Hardie, Laura and Greenwood, Darren
(2020)
Maternal iodine status in a multi-ethnic UK birth cohort: associations with child cognitive and educational development.
Paediatric and Perinatal Epidemiology.
(doi:10.1111/ppe.12719).
Abstract
Background: Maternal iodine requirements increase during pregnancy to supply thyroid hormones critical for fetal neurodevelopment. Iodine insufficiency may result in poorer cognitive or child educational outcomes but current evidence is sparse and inconsistent. Objectives: To quantify the association between maternal iodine status and child educational outcomes. Methods: Urinary iodine concentrations (UIC) and iodine/creatinine ratios (I:Cr) were measured in 6971 mothers at 26-28 weeks' gestation participating in the Born in Bradford cohort. Maternal iodine status was examined in relation to child school achievement (early years foundation stage (EYFS), phonics, and Key Stage 1 (KS1)), other learning outcomes, social and behavioural difficulties, and sensorimotor control in 5745 children aged 4-7 years. Results: Median (interquartile range) UIC was 76 µg/L (46, 120), and I:Cr was 83 µg/g (59, 121). Overall, there was no strong or consistent evidence to support associations between UIC or I:Cr and neurodevelopmental outcomes. For instance, predicted EYFS and phonics scores (primary outcomes) at the 25th vs 75th I:Cr percentiles (99% confidence intervals) were similar, with no evidence of associations: EYFS scores were 32 (99% CI 31, 33) and 33 (99% CI 32, 34), and phonics scores were 34 (99% CI 33, 35) and 35 (99% CI 34, 36), respectively. Conclusions: In the largest single study of its kind, there was little evidence of detrimental neurodevelopmental outcomes in children born to pregnant women with iodine insufficiency as defined by World Health Organization–outlined thresholds. Alternative functional biomarkers for iodine status in pregnancy and focused assessment of other health outcomes may provide additional insight.
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BiB_Iodine_cognitive_outcomes_FINAL_ACCEPTED
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More information
Accepted/In Press date: 31 July 2020
e-pub ahead of print date: 1 September 2020
Additional Information:
Funding Information:
Born in Bradford is only possible because of the enthusiasm and commitment of the Children and Parents in BiB. We are grateful to all the participants, health professionals, and researchers who have contributed to Born in Bradford. The authors thank Dr. Gillian Santorelli for advice relating to BiB data. This publication is independent research funded by the National Institute for Health Research (NIHR) Policy Research Programme (Assessing iodine status and associated health outcomes in British women during pregnancy, PR‐R10‐0514‐11004). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care.
Publisher Copyright:
© 2020 The Authors. Paediatric and Perinatal Epidemiology published by John Wiley & Sons Ltd
Keywords:
born in Bradford, child development, cognition, deficiency, iodine, nutrition, pregnancy
Identifiers
Local EPrints ID: 443556
URI: http://eprints.soton.ac.uk/id/eprint/443556
ISSN: 0269-5022
PURE UUID: 029f3fff-d6f0-4a73-8853-986b0863e096
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Date deposited: 01 Sep 2020 16:31
Last modified: 17 Mar 2024 05:50
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Contributors
Author:
Diane E. Threapleton
Author:
Charles Jonathan Peter Snart
Author:
Claire Keeble
Author:
Amanda H. Waterman
Author:
Elizabeth Taylor
Author:
Dan Mason
Author:
Stephen Reid
Author:
Rafaq Azad
Author:
Liam J.B. Hill
Author:
Sarah Meadows
Author:
Amanda McKillion
Author:
Janet E. Cade
Author:
Nigel A.B. Simpson
Author:
Paul M. Stewart
Author:
Michael Zimmermann
Author:
John Wright
Author:
Dagmar Waiblinger
Author:
Mark Mon-Williams
Author:
Laura Hardie
Author:
Darren Greenwood
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