Prenatal exposure to flame retardants linked to reading problems

Children exposed to flame retardants during pregnancy may have an increased risk of reading problems, according to a study.

Researchers from Columbia University in the US hypothesised that in-utero exposure to polybrominated diphenyl ethers (PBDEs) -- a type of flame retardant that is known to have adverse effects on brain development -- may alter the brain processes involved in reading.

The study, published in the journal Environmental International, analysed neuro-imaging data from 33 5-year-old children -- all novice readers -- who were first given a reading assessment to identify reading problems.

The researchers also used maternal blood samples, taken during pregnancy, to estimate prenatal exposure to PDBEs.

They found that children with a better-functioning reading network had fewer reading problems.

The study also showed that children with greater exposure to PDBEs had a less efficient reading network.

However, greater exposure did not appear to affect the function of another brain network involved in social processing that has been associated with psychiatric disorders such as autism spectrum disorder.

"Since social processing problems are not a common aspect of reading disorders, our findings suggest that exposure to PDBEs doesn't affect the whole brain -- just the regions associated with reading," said Amy Margolis, an assistant professor at Columbia University Vagelos College of Physicians and Surgeons.

Although exposure to PDBEs affected reading network function in the 5-year-olds, it did not have an impact on word recognition in this group, the researchers said.

The finding is consistent with a previous study, in which the effects of exposure to the compounds on reading were seen in older children but not in emergent readers.

"Our findings suggest that the effects of exposure are present in the brain before we can detect changes in behaviour," said Margolis.

"Future studies should examine whether behavioural interventions at early ages can reduce the impact of these exposures on later emerging reading problems," he said.