Project Summary
Depression is a prevalent, recurrent, and frequently chronic disorder that affects approximately 21% of
individuals in their lifetime and is associated with significant impairment and considerable public health burden.
To elucidate factors that contribute to the onset and development of depressive symptoms, the current project
seeks to test the role of alterations in peripheral cytokines as a biological mediator of associations between air
pollution exposure and depressive symptoms in adolescents. Specifically, the current project will utilize a
prospective longitudinal study of 120 adolescents to examine associations between air pollution exposure and
subsequent trajectories of depressive symptoms and immune markers. Through the direct assessment of
theorized biological mediators, use of repeated assessments, and creation of sophisticated air pollution exposure
estimates, we will overcome past roadblocks to progress and rigorously test a putative mediator of risk.
Leveraging stored blood samples collected as part of an ongoing parent study of social contributors to depression
during adolescence, this work will characterize air pollution exposure for study participants across multiple
timescales (Aim 1), which will then be utilized to determine dose-response associations between air pollution
and trajectories of depressive symptoms across a 6-month period (Aim 2). Lastly, it will probe peripheral immune
markers as putative mediations between air pollution and depressive symptoms, testing competing models of
cytokines (e.g., proinflammatory, Th-1, and Th-2) to determine the specificity of the immune markers in relation
to risk. Through this methodologically rigorous approach, we will be poised to conduct strong tests of directional
associations between air pollution exposure and depressive symptoms and to identify immunological parameters
that may mediate risk. In doing so, insights from this project will critically inform future hypotheses to elucidate
biological and psychological cascades that contribute to the adverse effects of air pollution exposure on mental
health to identify novel targets for intervention efforts and ultimately reduce the significant burdens associated
with depression.
