Presenting Author: Sheila Tripathy, Drexel University Dornsife School of Public Health

ABSTRACT

Background: While long-term exposure to ambient air pollution has been found to impact the immune system through systemic inflammation, it is unclear whether chronic pollutant exposures are associated with endotoxin stimulated inflammatory mediators.

Objectives: We examined associations between chronic exposures to outdoor air pollution and levels of both circulating and lipopolysaccharide (LPS) stimulated inflammatory mediators in a cohort of healthy adults.

Methods: Circulating levels of Interleukin-6 (IL-6), C-reactive protein (CRP) (n=392), and LPS-stimulated production of Interleukin-1β (IL-1β), IL-6, and Tumor Necrosis Factor-α (TNF-α) were measured in blood samples collected from 379 participants in the Adult Health and Behavior II cohort. Spatial air pollution exposure models developed for fine particulate matter (PM2.5), black carbon (BC), and lead (Pb), manganese (Mn), zinc (Zn), and iron (Fe) metal constituents of PM2.5 were used to assign pollutant exposures at participant’s geocoded addresses. Associations between individual pollutant exposures with circulating and stimulated inflammatory mediators were examined using linear regression models adjusting for age, sex, race, smoking status, body mass index (BMI), and years of education.

Results: Exposure to PM2.5 and BC were associated with higher LPS-stimulated IL-1β, IL-6, and TNF-α. Pb was associated with increased stimulated TNF-α and IL-1β. No pollutant exposures were associated with circulating levels of IL-6 or CRP.

Implications: Exposure to PM2.5 and BC associated with increased LPS-stimulated proinflammatory cytokine production a cohort of middle-aged adults. These results suggest that some chronic air pollution exposures may influence the responsiveness of the immune system, possibly increasing risk for future inflammatory conditions.

Authors: Sheila Tripathy; Ellen Kinnee, MS; Brett J. Tunno, DrPH, MPH, CPH; Stephen B. Manuck, PhD; Katarina Gray; Anna L. Marsland, PhD; Peter J. Gianaros, PhD; and Jane E. Clougherty, MSc, ScD.