Publication

Fine particulate air pollution (pm2.5) and the risk of acute ischemic stroke

OʼDonnell, Martin J.
Fang, Jiming
Mittleman, Murray A.
Kapral, Moira K.
Wellenius, Gregory A.
Citation
OʼDonnell, Martin J. Fang, Jiming; Mittleman, Murray A.; Kapral, Moira K.; Wellenius, Gregory A. (2011). Fine particulate air pollution (pm2.5) and the risk of acute ischemic stroke. Epidemiology 22 (3), 422-431
Abstract
Background: Short-term changes in levels of fine ambient particulate matter (PM2.5) may increase the risk of acute ischemic stroke; however, results from prior studies have been inconsistent. We examined this hypothesis using data from a multicenter prospective stroke registry. Methods: We analyzed data from 9202 patients hospitalized with acute ischemic stroke, having a documented date and time of stroke onset, and residing within 50 km of a PM2.5 monitor in 8 cities in Ontario, Canada. We evaluated the risk of ischemic stroke onset associated with PM2.5 in each city using a time-stratified case-crossover design, matching on day of week and time of day. We then combined these city-specific estimates using random-effects meta-analysis techniques. We examined whether the effects of PM2.5 differed across strata defined by patient characteristics and ischemic stroke etiology. Results: Overall, PM2.5 was associated with a -0.7% change in ischemic stroke risk per 10-mu g/m(3) increase in PM2.5 (95% confidence interval = -6.3% to 5.1%). These overall negative results were robust to a number of sensitivity analyses. Among patients with diabetes mellitus, PM2.5 was associated with an 11% increase in ischemic stroke risk (1% to 22%). The association between PM2.5 and ischemic stroke risk varied according to stroke etiology, with the strongest associations observed for strokes due to large-artery atherosclerosis and small-vessel occlusion. Conclusions: These results do not support the hypothesis that short-term increases in PM2.5 levels are associated with ischemic stroke risk overall. However, specific patient subgroups may be at increased risk of particulate-related ischemic strokes.
Funder
Publisher
Ovid Technologies (Wolters Kluwer Health)
Publisher DOI
10.1097/ede.0b013e3182126580
Rights
Attribution-NonCommercial-NoDerivs 3.0 Ireland