Leeds Institute of Cardiovascular & Metabolic Medicine, School of Medicine, University of Leeds, Leeds, UK.
Leeds Institute for Data Analytics, University of Leeds, Leeds, UK.
Paediatr Perinat Epidemiol. 2021 Mar;35(2):236-246. doi: 10.1111/ppe.12719. Epub 2020 Sep 1.
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.
To quantify the association between maternal iodine status and child educational outcomes.
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.
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.
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.
孕妇对碘的需求量在怀孕期间增加，以提供对胎儿神经发育至关重要的甲状腺激素。碘不足可能导致认知能力下降或儿童教育成果较差，但目前的证据稀少且不一致。
量化孕妇碘状况与儿童教育成果之间的关联。
在参与布拉德福德出生队列的 6971 名孕妇 26-28 周妊娠时测量尿碘浓度 (UIC) 和碘/肌酐比 (I:Cr)。在 5745 名 4-7 岁儿童中，检查了母体碘状况与儿童学校成绩（早期基础阶段 (EYFS)、拼音和关键阶段 1 (KS1)）、其他学习成果、社会和行为困难以及感觉运动控制之间的关系。
中位数（四分位距）UIC 为 76µg/L（46，120），I:Cr 为 83µg/g（59，121）。总体而言，没有强有力或一致的证据支持 UIC 或 I:Cr 与神经发育结果之间的关联。例如，在 I:Cr 百分位数的第 25 位与第 75 位（99%置信区间）预测的 EYFS 和拼音评分（主要结局）相似，没有关联的证据：EYFS 评分为 32（99%CI 31，33）和 33（99%CI 32，34），拼音评分为 34（99%CI 33，35）和 35（99%CI 34，36）。
在同类最大的单一研究中，在碘不足的孕妇所生的儿童中，几乎没有证据表明神经发育结果受到损害，正如世界卫生组织规定的阈值所定义的那样。在妊娠期间碘状况的替代功能生物标志物和对其他健康结果的重点评估可能会提供更多的见解。
