Abstract 11434: Air Pollution is Associated With Ischemic Stroke via Cardiogenic Embolism

Abstract

Introduction: Both individual and environmental factors influence stroke risk and the effect might differ across stroke subtypes. The prevalence of cardioembolic stroke is increasing in Asian and other developing countries, which may be associated with the ambient air pollution as well as an aging population. However, the association between air pollution and stroke subtype remains unclear. Hypothesis: This study investigated the impact of short-term exposure to air pollution on ischemic stroke subtype, while focusing on stroke caused via cardioembolism. Methods: From a nationwide multicenter prospective stroke registry database, 13,535 acute ischemic stroke patients hospitalized to 12 participating centers were enrolled in this study. Data on the hourly concentrations of particulate matter <10μm (PM 10 ), nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), ozone (O 3 ), and carbon monoxide (CO) were collected from 181 nationwide air pollution surveillance stations. The average values of these air pollutants over the 7 days prior to stroke onset from nearest air quality monitoring station in each patient were used to determine association with stroke subtype. Results: PM 10 and SO 2 concentrations were independently associated with an increased risk of cardioembolic stroke, as compared to large artery atherosclerosis and non-cardioembolic stroke. In sensitivity analyses, the proportion of cases of cardioembolic stroke was positively correlated with the PM 10 , NO 2 , and SO 2 quintiles. Moreover, seasonal (including Asian dust storms in spring and winter) and geographic (including polluted mid-sized cities) factors were related to an increased proportion of cardioembolic stroke, which may be attributed to the high levels of air pollution. Conclusions: Our findings suggest that the short-term exposure to air pollutants is associated with cardioembolic stroke subtype, and greater care should be taken for those susceptible to cerebral embolism during peak pollution periods. Public and environmental health policies to reduce air pollution could help slow down global increasing trends of cardioembolic stroke.