July 20, 2009

Pollution During Pregnancy Linked To Lower IQ

Air pollution during prenatal development may be partially to blame for a child's lower IQ, researchers reported on Monday.

Writing in the journal Pediatrics, researchers from the Columbia Center for Children's Environmental Health (CCCEH) at the Mailman School of Public Health found that exposure to air pollutants, called polycyclic aromatic hydrocarbons, or PAHs, can result in a child's lower intelligence quotient (IQ).

PAHs can come from burning substances such as coal, diesel, oil and gas, or tobacco.

Researchers studied 249 children born to New York City women, aged 18-35. The women were asked to wear air quality monitors attached to backpacks for 48 hours during the last months of pregnancy.

Each of the children was followed until age 5. They were given an intelligence test called the Wechsler Preschool and Primary Scale of the Intelligence. The researchers developed models to calculate the associations between prenatal PAH exposure and IQ.

They found that children who had been exposed to higher levels of PAH "“ defined as more than 2.26 nanograms per cubic meter "“ during prenatal development had full scale and verbal IQ scores that were 4.31 and 4.67 points lower, respectively than those of less exposed children.

"These findings are of concern because these decreases in IQ could be educationally meaningful in terms of school performance," said lead author Frederica Perera, DrPH, professor of Environmental Health Sciences and director of the CCCEH at Columbia University Mailman School of Public Health.

"The good news is that we have seen a decline in air pollution exposure in our cohort since 1998, testifying to the importance of policies to reduce traffic congestion and other sources of fossil fuel combustion byproducts."

"The decrease in full-scale IQ score among the more exposed children is similar to that seen with low-level lead exposure," she added.

"This finding is of concern because IQ is an important predictor of future academic performance, and PAHs are widespread in urban environments and throughout the world. Fortunately, airborne PAH concentrations can be reduced through currently available controls, alternative energy sources and policy interventions."

The study was funded by the National Institute of Environmental Health Sciences (NIEHS), a component of the National Institutes of Health, the U.S. Environmental Protection Agency and several private foundations.


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