New research has found that children of mothers who are considered to be living in poverty and who are exposed to high levels of air pollutants while still in the womb are more likely to score lower in IQ tests compared to those who were exposed to fewer pollutants in the womb and born to more economically secure mothers.
The study was published in the journal Neurotoxicology and Teratology by researchers from the Columbia Center for Children’s Environmental Health at the Mailman School of Public Health. Led by Dr. Frederica Perera, researchers analyzed data from 276 mother-child pairs living in urban areas from the mother’s pregnancy to the child’s early childhood.
They measured the amount exposure to air pollutants (specifically, polycyclic aromatic hydrocarbons) of the pregnant mother and prenatal child through cord blood samples. Polycyclic aromatic hydrocarbons come from vehicle smoke emissions, oil and coal burning, tobacco smoke, etc.
They also asked the mothers to report their maternal material hardship during pregnancy and at several points during their child’s early childhood. Material hardship was measured through unmet basic needs with regard to food, clothing and housing.
With the group of mothers who reported greater material hardship, the children at age 5 who had high exposure levels of PAH scored significantly lower on IQ tests compared to children with low exposure.
However, this was not the case for mothers who were not economically challenged but whose children have high PAH levels. These children did not have significantly lower IQ scores.
“The findings add to other evidence that socioeconomic disadvantage can increase the adverse effects of toxic physical 'stressors' like air pollutants,” concluded the study.
Lead author Perera said, “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.”
Sources: May 1, 2015. "Prenatal Air Pollution and Poverty: The Combination That Can Lower a Kid’s IQ". parents.com April 30, 2015. "Prenatal Air Pollution + Poverty = Lower IQ in Child". psychcentral.com