Maternal iodine status in a multi-ethnic UK birth cohort: associations with autism spectrum disorder.


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Authors
Cromie, Kirsten Jade 
Threapleton, Diane Erin 
Snart, Charles Jonathan Peter 
Taylor, Elizabeth 
Mason, Dan 
Abstract

BACKGROUND: Maternal iodine requirements increase during pregnancy to supply thyroid hormones essential for fetal brain development. Maternal iodine deficiency can lead to hypothyroxinemia, a reduced fetal supply of thyroid hormones which, in the first trimester, has been linked to an increased risk of autism spectrum disorder (ASD) in the child. No study to date has explored the direct link between maternal iodine deficiency and diagnosis of ASD in offspring. METHODS: Urinary iodine concentrations (UIC) and iodine/creatinine ratios (I:Cr) were measured in 6955 mothers at 26-28 weeks gestation participating in the Born in Bradford (BiB) cohort. Maternal iodine status was examined in relation to the probability of a Read (CTV3) code for autism being present in a child's primary care records through a series of logistic regression models with restricted cubic splines. RESULTS: Median (inter-quartile range) UIC was 76 μg/L (46, 120) and I:Cr was 83 μg/g (59, 121) indicating a deficient population according to WHO guidelines. Ninety two children (1·3%) in our cohort had received a diagnosis of ASD by the census date. Overall, there was no evidence to support an association between I:Cr or UIC and ASD risk in children aged 8-12 years (p = 0·3). CONCLUSIONS: There was no evidence of an increased clinical ASD risk in children born to mothers with mild-to-moderate iodine deficiency at 26 weeks gestation. Alternative functional biomarkers of exposure and a wider range of conditions may provide further insight.

Description
Keywords
Autism spectrum disorder, Deficiency, Fetal development, Iodine, Pregnancy, Thyroid, Autism Spectrum Disorder, Child, Female, Fetal Development, Gestational Age, Humans, Iodine, Pregnancy, United Kingdom
Journal Title
BMC Pediatr
Conference Name
Journal ISSN
1471-2431
1471-2431
Volume Title
20
Publisher
Springer Science and Business Media LLC
Sponsorship
National Institute for Health Research (PR-R10-0514-11004)