UK: Maternal iodine deficiency do not lead to an increased autism risk in offspring, reveals results from a recent study in the journal BMC Pediatrics.
There is an increase the requirement of maternal iodine during pregnancy to supply thyroid hormones essential for the development of fetal brain. Iodine deficiency in mothers can lead to hypothyroxinemia, a reduced fetal supply of thyroid hormones which. Hypothyroxinemia in the first trimester has been linked to an increased risk of autism spectrum disorder (ASD) in the child. No study till date has however, explored the direct link between maternal iodine deficiency and ASD diagnosis in offspring. Considering this Darren Charles Greenwood, University of Leeds, Leeds, UK, and colleagues aimed to investigate he association between maternal iodine status in mid-pregnancy and an ASD diagnosis in the child, across a continuous range of urinary iodine concentrations.
For the purpose, the researchers measured urinary iodine concentrations (UIC) and iodine/creatinine ratios (I:Cr) 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.
Key findings of the study include:
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 the cohort had received a diagnosis of ASD by the census date.
There was no evidence to support an association between I:Cr or UIC and ASD risk in children aged 8–12 years.
"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," concluded the authors.
The study, "Maternal iodine status in a multi-ethnic UK birth cohort: associations with autism spectrum disorder," is published in the journal BMC Pediatrics.
DOI: https://bmcpediatr.biomedcentral.com/articles/10.1186/s12887-020-02440-y