Traffic and fossil fuels for heat, electricity biggest factors, study suggests
WebMD News from HealthDay
By Dennis Thompson
HealthDay Reporter
WEDNESDAY, Nov. 5, 2014 (HealthDay News) -- Pregnant women exposed to air pollution are five times more likely to have children who develop behavior problems related to attention-deficit/hyperactivity disorder, or ADHD, a new study reports.
A child's risk of ADHD symptoms by age 9 appears to increase dramatically if they were exposed in the womb to high levels of air pollutants called polycyclic aromatic hydrocarbons (PAHs), researchers at Columbia University reported.
Compared to children with low PAH exposure, children exposed to high levels are more likely to have both an increased number of symptoms and more intense symptoms, said lead author Frederica Perera, a professor of environmental health sciences at Columbia's Mailman School of Public Health in New York City.
Pollutants and other environmental factors likely interact with an unborn child's genetics to increase their risk of ADHD later in life, said Stephen Faraone, a professor of psychiatry at SUNY Upstate Medical University in Syracuse, N.Y., who reviewed the study's findings.
"We think it means as the brain is developing, these toxins change something in the functional connectivity or structure of the brain that downstream leads to ADHD," Faraone said. He noted that studies like this prove an association but not a direct cause-and-effect link between air pollution and ADHD.
The study is published in the Nov. 5 online edition of the journal PLoS One.
Polycyclic aromatic hydrocarbons are chemicals formed during the incomplete burning of coal, oil, gas, wood, garbage or other organic substances, according to the U.S. Centers for Disease Control and Prevention. Traffic, home heating furnaces and coal-burning power plants are prime sources of PAHs, the researchers noted.
Children exposed to PAHs in the womb were particularly likely to display signs of inattentiveness that are related to ADHD, Perera said.
These symptoms include reluctance to engage in tasks that require sustained mental effort, difficulty maintaining attention in class, an inability to listen to what's being said to them, and a lack of follow-through or completion of tasks, according to the researchers.
The findings from this study build on previous Columbia University studies linking prenatal PAH exposure with behavioral and mental issues, according to a university news release. These include associations with developmental delays at age 3, reduced IQ at age 5, and symptoms of anxiety, depression and attention problems at ages 6 and 7.
The current study included more than 230 nonsmoking pregnant women from New York City, and their children.
The researchers tested PAH exposure by looking for the chemicals both in the mothers' blood and blood from the umbilical cords.
"It reflects not only that the chemicals have been brought into the body, they have been activated through metabolism and they have bound to DNA," Perera said.
source : ADHD Linked to Expectant Moms' Smog Exposure
