Unborn Children into Poverty, Exposed to Pollution More Likely to Have Lower IQ: Study

Children born into poverty and exposed to high levels of pollution in utero appear to be more likely to have lower IQ scores later in childhood, according to the findings of a new study. 

Researchers found children born to mothers experiencing economic hardship and who were also exposed to polycyclic aromatic hydrocarbons (PAH) had significantly lower scores on IQ tests at the age of five. The findings were published online April 29, in the journal Neurotoxicology and Teratology.

The research was a part of a larger study, the urban birth cohort study in New York City, lead by Frederica Perera, PhD, DrPH and director of the Columbia Center for Children’s Environmental Health (CCCEH) at Columbia University’s Mailman School of Public Health.

Perera’s team found mothers who were exposed to PAH during pregnancy with high levels of PAH in the cord blood of their children and experienced economic hardship had children who had lower IQ scores than children who also were exposed to pollution during pregnancy but had greater economic security.

The children with lower IQ scores and higher levels of PAH in the cord blood also tested lower on perceptual reasoning and working memory compared to those children with lower levels of PAH in the cord blood.

The team followed 276 mother-child pairs from pregnancy to early childhood. Mothers self reported economic hardship at multiple points during the pregnancy through early childhood. Hardship was measured based on the levels of an individual’s unmet basic needs, including food, clothing and housing.

PAH is ubiquitous in the environment and is released during emissions from motor vehicles, oil, and coal-burning for home heating. It is also released in power generation, tobacco smoke, and other combustion sources.

The team previously reported PAH exposure during pregnancy was associated with development delays at the age of three. It was also linked to reduced verbal and full scale IQ at age five and symptoms of anxiety and depression at age seven.

A 2013 study revealed air pollution may increase a child’s risk of developing autism if their mothers were exposed to the pollutants during pregnancy. These women were twice as likely to give birth to a child who would later develop autism.

The same relationship between high levels of PAH in cord blood and IQ were not observed in the group of children whose mothers did not experience economic hardship.

Researchers say this adds to the evidence that socioeconomic disadvantages can increase the adverse effects of toxic physical stressors, like pollutants. Toxic exposure, including air pollution, are “disproportionately high in communities of color” as well as areas that experience chronic levels of poverty.

A study published last year indicated that minorities are more likely to live in the path of harmful air pollution. The research revealed polluters specifically target minority populations because of the decreased likelihood that authorities will advocate for these groups.

“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.

Researchers call for the introduction of a multifaceted approach to reduce PAH exposure and alleviate material hardship to protect the developing fetuses and young children.