Poor mothers exposed to air pollution may have children who score significantly lower on IQ tests at age five, as compared to children born to mothers without similar adversity.
The finding that socioeconomic disadvantage can increase the adverse effects of toxic physical “stressors” like air pollutants confirms the need for a multi-faceted approach to protect at risk mothers.
Researchers at the Columbia Center for Children’s Environmental Health (CCCEH) at the Mailman School of Public Health explain that the air pollution comes from high levels of PAH (polycyclic aromatic hydrocarbons).
PAH are ubiquitous in the environment from emissions from motor vehicles, oil, and coal-burning for home heating and power generation, tobacco smoke, and other combustion sources.
The findings by appear in the journal Neurotoxicology and Teratology.
For the study, researchers followed 276 mother-child pairs, a subset of CCCEH’s ongoing urban birth cohort study in New York City, from pregnancy through early childhood.
Mothers self-reported maternal material hardship during pregnancy and at multiple time points through early childhood. Material hardship is a measure used to assess an individual’s unmet basic needs with regard to food, clothing, and housing.
The Columbia researchers, led by Frederica Perera, Ph.D., Dr.P.H., previously reported that prenatal exposure to airborne PAH during gestation was associated with development delay at age three, reduced verbal and full scale IQ at age five, and symptoms of anxiety and depression at age seven.
At child age seven years, researchers used the Wechsler Intelligence Scale for Children to assess IQ.
The researchers observed that, among children whose mothers reported greater material hardship, the group with high levels of PAH-DNA scored significantly lower on tests of full scale IQ, perceptual reasoning, and working memory compared to those children with lower levels of PAH-DNA.
Researchers also discovered statistically significant interactions were observed between both prenatal and persistent material hardship and high levels of PAH exposure on children’s working memory scores. The same significant relationships between PAH exposure and IQ were not observed among children whose mothers had not experienced the economic challenges.
The findings add to other evidence that socioeconomic disadvantage can increase the adverse effects of toxic physical “stressors” like air pollutants.
“The findings support policy interventions to reduce air pollution exposure in urban areas as well as programs to screen women early in pregnancy to identify those in need of psychological or material support,” said Perera, senior author of the paper.