JAMA: A small imaging study suggests prenatal exposure to polycyclic aromatic hydrocarbons (PAHs), the toxic air pollution caused in part by vehicle emissions, coal burning and smoking, may be bad for children’s brains and may contribute to slower processing speeds and behavioral problems, including attention-deficit-hyperactivity-disorder (ADHD) symptoms, according to an article published online by JAMA Psychiatry.
PAHs are caused by the incomplete combustion of organic materials. In
addition to outdoor air pollution, sources of indoor air pollution
caused by PAHs can be cooking, smoking and space heaters. PAHs can cross
the placenta and damage fetal brains and animal experiments suggest
prenatal exposure can impair behavior and learning, according to study
Bradley S. Peterson, M.D., of Children’s Hospital Los Angeles, and
coauthors conducted an imaging study that included 40 minority urban
school-aged children born to Latin (Dominican) or African American
women. The children were followed from the fetal period to ages 7 to 9
years old. Their mothers completed prenatal PAH monitoring and prenatal
The authors found an association between increased prenatal PAH
exposure and reductions in brain white matter in children later in
childhood that was confined almost exclusively to the left hemisphere of
the brain and involved almost its entire surface. Reduced white matter
surface on the left side of the brain was associated with slower
processing during intelligence testing and behavioral problems,
including ADHD symptoms and conduct disorder problems, according to the
results. The neurodevelopmental outcomes in children were measured
through intelligence testing and a behavior checklist.
The authors note the small size of their study as well as other limitations in the research.
“If confirmed, our findings have important public health implications
given the ubiquity of PAHs in air pollutants among the general
population,” the study concludes.
(JAMA Psychiatry. Published online March 25, 2015. doi:10.1001/jamapsychiatry.2015.57. Available pre-embargo to the media at http://media.jamanetwork.com.)
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