PROJECT SUMMARY / ABSTRACT
More than one in five adolescents will experience a mental health disorder, including depression and anxiety,
and the prevalence of these conditions is increasing. Among adolescents, depression and anxiety are linked to
increased risk of suicide, a leading cause of death in this age group. Identifying underlying and modifiable
contributors to these conditions is crucial as current research and interventions focus on screening and
treatment rather than prevention. Here, we posit that air pollution, in addition to genetic susceptibility, social
determinants, familial and school issues, and other factors, is a contributor to mental health disorders.
Toxicological studies demonstrate that fine particulate matter (PM2.5) and traffic-related air pollution (TRAP) are
neurotoxic, and epidemiologic studies consistently link these pollutants to reduced cognitive abilities and
increased externalizing behaviors. However, few studies have prospectively evaluated the role of air pollution
exposure on mental health disorders in childhood. Recently, we found that childhood air pollution exposure is
associated with increased risk for depression and anxiety at age 12 years. However, the role of air pollution in
the onset and persistence of mental health disorders during adolescence, and changes in brain structure,
organization, and function linked to these outcomes, remain poorly understood. Therefore, we hypothesize that
exposure to air pollution during critical periods of brain development, including adolescence, is associated with
adverse mental health outcomes. We will leverage existing longitudinal data from the Cincinnati Childhood
Allergy and Air Pollution Study (CCAAPS) and the Health Outcomes and Measures of the Environment
(HOME) Study, two prospective cohorts located in Cincinnati, Ohio, to address this hypothesis. Both cohorts
have been followed from birth and evaluated with concordant measures of mental health and neuroimaging at
age 12 years. We will conduct new follow-up at age 18 years to assess the onset and persistence of mental
health outcomes through adolescence and apply validated models for PM2.5 and TRAP to characterize air
pollution exposure from conception through age 18 years. We will also acquire novel neuroimaging outcomes,
including brain -aminobutyric acid and glutathione concentrations accompanied by anatomical and functional
magnetic resonance imaging. Our aims are to: 1) determine the association between exposure to PM2.5 and
TRAP during distinct developmental periods and the onset and persistence of mental health outcomes in
adolescence; 2) determine the association between exposure to PM2.5 and TRAP during distinct developmental
periods and neuroimaging outcomes in late adolescence; and 3) determine whether changes in brain volume,
organization, metabolism, and function mediate associations between PM2.5 and TRAP exposure and mental
health outcomes. Examining air pollution as a novel and modifiable risk factor will provide critical data to guide
primary prevention aimed at reducing the burden of mental health disorders in adolescence.
