Abstract TP211: Fine Particulate Matter (PM2.5) and the Risk of Stroke in the REGARDS Cohort

Abstract

Introduction: Recent work has suggested that there is some association between acute exposures to fine particulate matter with aerodynamic diameter less than or equal to 2.5 micrometers (PM2.5) and ischemic stroke; however, the evidence is conflicting. Thus, we assessed whether PM2.5 was associated with ischemic stroke in participants in the Reasons for Geographic And Racial Differences in Stroke (REGARDS) cohort. Methods: We used a time-stratified case-crossover design to determine if exposure to PM2.5 was associated with an increased risk of ischemic stroke. We fit conditional logistic regression models to determine the odds ratio of ischemic stroke for those exposed to moderate (PM2.5 15-40 μg/m3) relative to good (PM2.5 ≤ 15 μg/m3) levels of PM2.5. We adjusted for temperature at the time of exposure, and assessed whether the association differed by region of residence (stroke belt vs. non-belt regions). Results: Among 442 participants who experienced an incident ischemic stroke in REGARDS, we found that there was no association with PM2.5 exposure (OR: 0.89, 95% CI: 0.69-1.15), and that there was no impact of region of residence on these results (p for interaction=0.14). Conclusions: We did not confirm earlier research indicating that there is an acute association between PM2.5 and ischemic stroke. More research is needed to understand these conflicting results, and to assess the impact of longer term exposures of PM2.5 on stroke incidence.