Prenatal Exposure to Air Pollution Linked to Behavior-Related Brain Changes

Prenatal exposure to air pollution (AP) negatively affects the lateral ventricles (LV) and corpus callosum (CC) volumes in the brain, which may lead subsequent behavioral problems in children, according to a study published in the journal Environmental Research.

In this analysis, called the Brain Development and Air Pollution Ultrafine Particles in School Children (BREATHE) study, researchers recruited 186 typically developing children between the ages of 8-12 who underwent structural MRI scans using automated tissue segmentation. Subsequently, they assessed behavioral problems utilizing the Strengths and Difficulties Questionnaire (SDQ) and the criteria of the Attention Deficit Hyperactivity Disorder DSM-IV list, retrospectively measuring prenatal PM levels were retrospectively estimated at the mothers’ residential addresses during pregnancy with land use regression (LUR) models.

To determine whether brain structures might be affected by prenatal PM2.5 exposure, linear regression models were run and adjusted for age, sex, intracranial volume (ICV), maternal education, home socioeconomic vulnerability index, birthweight and mothers’ smoking status during pregnancy. The researchers tested for associations between brain changes and behavioral outcomes using negative binomial regressions and adjusted for age, and sex.

According to the results of the study, prenatal PM2.5 levels ranged from 11.8 to 39.5 μg/m3 during the third trimester of pregnancy, and an interquartile range increase in PM2.5 level (7 μg/m3) was notably linked with a decrease in the body CC volume (mm3) which corresponded to a 5% decrease of the mean body CC volume independently of ICV, age, sex, maternal education, socioeconomic vulnerability index at home, birthweight and mothers’ smoking status during the third trimester of pregnancy.

“In conclusion, this study suggests that prenatal exposure to PM2.5 is associated with changes on the CC volume in pre-adolescent children, even for levels not exceeding the limit target values established in the European Union,” the researcher authors wrote. “We have replicated the experimental findings in mice using a neuroimaging Region of Interest approach, but we went beyond by showing that the consequences of this air pollution-related CC volume reduction might be an increase in behavioral problems. Future larger and prospective studies are needed to confirm these findings in children.”