Researchers at Children’s Hospital Los Angeles and Columbia University found a “powerful” dose-response relationship between young children’s exposures to a common air pollutant, measurable brain disturbances, and cognitive and behavioral problems. The study appeared in JAMA Psychiatry.
The researchers studied the brains of 40 minority youth that are part of a larger cohort they have been following for over nine years since birth. They focused on the impacts of exposures to polycyclic aromatic hydrocarbons (PAHs) during fetal development. PAHs are known neurotoxins that come from emissions from motor vehicles, oil and coal burning, fires, tobacco smoke and charred foods, according to a press release about the study. “PAH readily crosses the placenta and affects an unborn child’s brain; earlier animal studies showed that prenatal exposure impaired the development of behavior, learning and memory.”
“We detected a dose-response relationship between increased prenatal PAH exposure (measured in the third trimester but thought to index exposure for all of gestation) and reductions of the white matter surface in later childhood that were confined almost exclusively to the left hemisphere of the brain and that involved almost its entire surface,” wrote the researchers. “Reduced left hemisphere white matter was associated with slower information processing speed during intelligence testing and with more severe externalizing behavioral problems, including attention-deficit/hyperactivity disorder symptoms and conduct disorder problems.”
“This is the largest MRI study to date of how early life exposure to air pollutants, specifically PAH, affect the developing mind,” one of the authors said in the press release. “Our findings suggest that PAH are contributors to ADHD and other behavioral problems due to the pollutants’ disruptive effects on early brain development.”
Peterson BS, Rauh VA, Bansal R, and et al. “EFfects of Prenatal Exposure to Air Pollutants (polycyclic Aromatic Hydrocarbons) on the Development of Brain White Matter, Cognition, and Behavior in Later Childhood.” JAMA Psychiatry, March 25, 2015. doi:10.1001/jamapsychiatry.2015.57. (Abstract)
Prenatal exposure to common air pollution linked to cognitive, behavioral impairment (Children’s Hospital Los Angeles Saban Research Institute press release on ScienceDaily, March 25, 2015)