Children were followed from infancy to age 7, when parents completed the Behavioral Assessment System for Children, 2nd Edition (BASC-2), assessing attention deficit hyperactivity disorder (ADHD) and related symptoms including attention problems, aggression, conduct problems and atypical behavior. Of the 762 children initially enrolled in the study, 576 were included in the final analysis at 7 years of age.
Results showed that children who were exposed to the highest third amount of TRAP during the first year of life were more likely to have hyperactivity scores in the "at risk" range when they were 7 years old. The "at risk" range for hyperactivity in children means that they need to be monitored carefully because they are at risk for developing clinically important symptoms.
"Several biological mechanisms could explain the association between hyperactive behaviors and traffic-related air pollution," Newman says, including narrowed blood vessels in the body and toxicity in the brain's frontal cortex.
Newman notes that the higher air pollution exposure was associated with a significant increase in hyperactivity only among those children whose mothers had greater than a high school education. Mothers with higher education may expect higher achievement, he says, affecting the parental report of behavioral concerns.
"The observed association between traffic-related air pollution and hyperactivity may have far-reaching implications for public health," Newman says, noting that studies have shown that approximately 11 percent of the U.S. population lives within 100 meters of a four-lane highway and that 40 percent of children attend school within 400 meters of a major highway.
"Traffic-related air pollution is one of many factors associated with changes in neurodevelopment, but it is one that is potentially preventable."
|Contact: Keith Herrell|
University of Cincinnati Academic Health Center