Diane E Threapleton1, Charles J P Snart1, Claire Keeble1,2, Amanda H Waterman3, Elizabeth Taylor1, Dan Mason4, Stephen Reid5, Rafaq Azad4, Liam J B Hill3, Sarah Meadows6,7, Amanda McKillion6,7, Nisreen A Alwan8,9, Janet E Cade10, Nigel A B Simpson11, Paul M Stewart12, Michael Zimmermann13, John Wright4, Dagmar Waiblinger4, Mark Mon-Williams3, Laura J Hardie1, Darren C Greenwood1,2. 1. Leeds Institute of Cardiovascular & Metabolic Medicine, School of Medicine, University of Leeds, Leeds, UK. 2. Leeds Institute for Data Analytics, University of Leeds, Leeds, UK. 3. School of Psychology, University of Leeds, Leeds, UK. 4. Bradford Institute for Health Research, Bradford Teaching Hospitals NHS Foundation Trust, Bradford, UK. 5. Earth Surface Science Institute, School of Earth and Environment, University of Leeds, Leeds, UK. 6. Elsie Widdowson Laboratory, University of Cambridge, Cambridge, UK. 7. NIHR Nutritional Biomarker Laboratory, MRC Epidemiology Unit, University of Cambridge, Cambridge, UK. 8. Faculty of Medicine, School of Primary Care and Population Sciences, Southampton General Hospital, University of Southampton, Southampton, UK. 9. NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, UK. 10. Nutritional Epidemiology Group, School of Food Science & Nutrition, University of Leeds, Leeds, UK. 11. Division of Women's and Children's Health, School of Medicine, University of Leeds, Leeds, UK. 12. Faculty of Medicine and Health, University of Leeds, Leeds, UK. 13. Laboratory for Human Nutrition, Institute of Food, Nutrition and Health, ETH Zurich, Zürich, Switzerland.
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.
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.
Authors: Dal Lae Ju; Sun Wook Cho; Chae Won Chung; Young Ah Lee; Gi Jeong Cheon; Young Joo Park; Choong Ho Shin; Jong Kwan Jun; June-Key Chung; Sue K Park; YoonJu Song Journal: Eur J Nutr Date: 2022-08-10 Impact factor: 4.865
Authors: Diane E Threapleton; Dagmar Waiblinger; Charles J P Snart; Elizabeth Taylor; Claire Keeble; Samina Ashraf; Shazia Bi; Ramzi Ajjan; Rafaq Azad; Neil Hancock; Dan Mason; Stephen Reid; Kirsten J Cromie; Nisreen A Alwan; Michael Zimmermann; Paul M Stewart; Nigel A B Simpson; John Wright; Janet E Cade; Laura J Hardie; Darren C Greenwood Journal: Nutrients Date: 2021-01-14 Impact factor: 5.717
Authors: Anna M Monaghan; Maria S Mulhern; Emeir M Mc Sorley; J J Strain; Theresa Winter; Edwin van Wijngaarden; Gary J Myers; Philip W Davidson; Conrad Shamlaye; Jude Gedeon; Alison J Yeates Journal: J Nutr Sci Date: 2021-08-31