Synergism of Short-Term Air Pollution Exposures and Neighborhood Disadvantage on Initial Stroke Severity

Background and Purpose-Little is known about the relation between environment and stroke severity. We investigated associations between environmental exposures, including neighborhood socioeconomic disadvantage and short-term exposure to airborne particulate matter <2.5 mu m and ozone, and their interactions with initial stroke severity. Methods-First-ever ischemic stroke cases were identified from the Brain Attack Surveillance in Corpus Christi project (2000-2012). Associations between pollutants, disadvantage, and National Institutes of Health Stroke Scale were modeled using linear and logistic regression with adjustment for demographics and risk factors. Pollutants and disadvantage were modeled individually, jointly, and with interactions. Results-Higher disadvantage scores and previous-day ozone concentrations were associated with higher odds of severe stroke. Higher levels of particulate matter <2.5 mu m were associated with higher odds of severe stroke among those in higher disadvantage areas (odds ratio, 1.24; 95% confidence interval, 1.00-1.55) but not in lower disadvantage areas (odds ratio, 0.82; 95% confidence interval, 0.56-1.22; P interaction = 0.097). Conclusions-Air pollution exposures and neighborhood socioeconomic status may be important in understanding stroke severity. Future work should consider the multiple levels of influence on this important stroke outcome.