Air Pollution Exposure and Prefrontal Connectivity in Early Adolescence
Megan M. Herting1, Dora Cserbik1, Claire E. Campbell1, Sandrah P. Eckel1, Kiros Berhane2, Rob McConnell1, Joel Schwartz3, Wesley K. Thompson4, Chun Chan4, Jiu-Chiuan Chen1
1University of Southern California, Los Angeles, CA, USA; 2Columbia University, New York City, NY, USA; 3Harvard University, Cambridge, MA, USA; 4University of California San Diego, CA, USA
Background: Emerging evidence indicates that fine particulate matter (aerodynamic diameter <2.5 μm; PM2.5) exposure is associated with increased mental health problems, albeit with mixed results. A fundamental gap in knowledge is the potential effects of exposure on emotional neurodevelopment during sensitive periods of maturation, such as the transition to adolescence when human brains undergo drastic remodeling.
Methods: The current project is the first large-scale U.S. population-based study to examine how PM2.5 exposure influences structural connectivity of the prefrontal cortex and subsequent emotional behavior in pre-adolescents. The current proposal leverages the nationwide longitudinal Adolescent Brain Cognitive Development (ABCD) study (N=11,873) to examine how annual ambient PM2.5 exposure estimated at the residential locations during ages 9-10 is associated with concurrent structural prefrontal white matter connectivity as well as influences emotional health outcomes at 1-year follow-up. We will also explore a potential mediating effect of prefrontal connectivity between the association of PM2.5 exposure and emotional health outcomes.
Results: Using a novel hybrid spatiotemporal PM2.5 exposure model, we found substantial within- and between-site variability in annual PM2.5 concentrations of residential exposure for ABCD participants across the 21 study sites. Moreover, exposures were largely below the standards set by the U.S. and World Health Organization, which suggests that findings from our study will provide important epidemiologic data on developmental neurotoxicity at low exposure levels that are critical to the continuing review and risk assessment for National Ambient Air Quality Standard. Moving forward, we aim to test the hypothesis that increased PM2.5 at ages 9-10 years will be associated with 1) white matter connectivity between the prefrontal cortex and brain regions involved in emotional processing; and 2) greater internalizing and externalizing problems as assessed by the Child Behavioral Checklist (CBCL) and Kiddie Schedule for Affective Disorders and Schizophrenia assessment.
Conclusions: Given urban air pollution exposure is common but can be reduced by behavioral changes and environmental regulations, the findings from the current study may have the potential to impact policy as well as identify better pre-clinical biomarkers as potential targets for early intervention.