Abstract 16338: A Case-Crossover Study of Short Term Effects of Air Pollutants on Stroke in Gunma, Japan
Introduction: Accumulating evidence links the elevated risk for cardiovascular mortality or hospitalization with exposure to air pollution, such as: fine particles <2.5μm in aerodynamic diameter (PM2.5), nitrogen Oxides(NOX) and nitrogen dioxide(NO2). NOx are important sources of air pollution which have toxicological effect on public health. However, the evidence regarding the association between air pollution and acute cerebral events, such as stroke, is limited. This study aimed to identify the associations between incidence of stroke with air pollutants including PM2.5, NOx and NO2.
Methods: The association between air quality and stroke was evaluated using a case-crossover design in Gunma Prefecture (population ~2million; area 6,363km2), Japan. Cases with stroke were identified through the Gunma Prefectural Ambulance Activity Database in 2015. Our exclusion criteria were: arrests with an obvious preceding noncardiac event such as trauma, poisoning, or drowning, leaving only those events that were presumed to have cardiac etiology. Air quality data from the nearest station (among eight 24-hr monitoring) was for day of the event (lag 0) and for lag 1, lag 2, and lag 3. Conditional logistic regression was used for unadjusted analysis and adjusted for temperature and humidity.
Results: There were 3612 strokes among the total of 53006 emergency cases from January to December in 2015. Daily lag3 NO2 level had significant association with incidence of stroke adjusted for temperature and humidity (OR: 1.002; 95%CI: 1.000, 1.005; p value: 0.048) model. No effects were found for PM2.5 and NOX.
Conclusions: The increased risk of stroke is associated with NO2 level of 3 days before the event but not with PM2.5 and NOx.
Author Disclosures: B. Zhao: None. F. Salimi: None. F. Johnston: None. K. Oshima: None. M. Kurabayashi: None. K. Negishi: None.
- © 2016 by American Heart Association, Inc.