Exposure to high levels of traffic-related air pollution at age 1 may lead to structural changes in the brain at the age of 12 which can influence the development of various physical and mental processes, warns a study.
The researchers found that children with higher levels of air pollution exposure at birth had reductions at age 12 in gray matter volume and cortical thickness as compared to children with lower levels of exposure.
Gray matter includes regions of the brain involved in motor control as well as sensory perception, such as seeing and hearing. Cortical thickness reflects the outer gray matter depth.
The study, published online in the journal PLOS One, found that specific regions in the frontal and parietal lobes and the cerebellum were affected with decreases on the order of three to four per cent.
"The results of this study, though exploratory, suggest that where you live and the air you breathe can affect how your brain develops," said lead author of the study Travis Beckwith, PhD, a research fellow at Cincinnati Children's Hospital Medical Center in the US.
"While the percentage of loss is far less than what might be seen in a degenerative disease state, this loss may be enough to influence the development of various physical and mental processes," Beckwith said.
For the study, the researchers used magnetic resonance imaging to obtain anatomical brain images from 147 kids.
These children are a subset of the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS), which recruited volunteers prior to the age of six months to examine early childhood exposure to traffic-related air pollution and health outcomes.
The volunteers in the CCAAPS had either high or low levels of pollution exposure during their first year of life.
The researchers estimated exposure using an air sampling network of 27 sites in the Cincinnati area, and 24/7 sampling was conducted simultaneously at four or five sites over different seasons.
Participating children and their caregivers completed clinic visits at ages 1, 2, 3, 4, 7 and 12.
Previous studies of traffic-related air pollution suggest that it contributes to neurodegenerative diseases and neurodevelopmental disorders.