Ambient air pollution and risk for ischemic stroke and transient ischemic attack

Abstract

Background Data on the association between air pollution and cerebrovascular disease in the US are limited. The objective of this study was to investigate the association between short-term exposure to ambient air pollution and risk of ischemic cerebrovascular events in a US community. Methods Daily counts of ischemic strokes/TIAs (2001–2005) were obtained from the population-based Brain Attack Surveillance in Corpus Christi (BASIC) Project. Daily particulate matter <2.5μm in diameter (PM2.5), ozone (O3), and meteorological data were obtained from Texas Commission on Environmental Quality. To examine the association between PM2.5 and stroke/TIA risk, Poisson regression was used. Separate models included same day PM2.5, PM2.5 lagged 1–5 days, and an averaged lag effect. All models were adjusted for temperature, day of week and temporal trends in stroke/TIA. The effects of O3 were also investigated. Results Median PM2.5 was 7.0 μg/m3 (Inter Quartile Range (IQR): 4.8–10.0). There were borderline significant associations between same day (RR=1.03, 95% CI:0.99–1.07 for an IQR increase in PM2.5) and previous day (RR=1.03, 95% CI:1.00–1.07) PM2.5 and stroke/TIA risk. These associations were independent of O3, which demonstrated similar associations with stroke/TIA risk (same day RR=1.02, 95% CI: 0.97–1.08 and previous day RR=1.04, 95% CI: 0.99–1.09) in two pollutant models. Inference We observed associations between recent PM2.5 and O3 exposure and ischemic stroke/TIA risk even in this community with relatively low pollutant levels. This study provides data on environmental exposures and stroke risk in the US and suggests future research on ambient air pollution and stroke is warranted.

Cardiovascular Emergency Hospital Visits and Hourly Changes in Air Pollution

“…Specific cardiovascular events considered to be associated with air pollution include ischemic heart disease, 1 heart failure, 2 cardiac arrhythmia/arrest, 3 and ischemic stroke. 4 However, the findings for hemorrhagic stroke remain inconsistent. Most such studies in Western countries have linked the levels of air pollutants to ischemic but not hemorrhagic stroke.…”

Outdoor Air Pollution and Incidence of Ischemic and Hemorrhagic Stroke

“…1 Several studies have examined the acute effects of outdoor air pollution on stroke using daily time series and case-crossover study designs. [2][3][4][5][6][7][8][9] Although a number of these studies have examined mortality and others have used hospital admissions as a proxy for incident cases, a few have used population case registers, which aim to capture all incident cases. 4,5 A number of these acute effects studies have reported associations between outdoor air pollutants and ischemic stoke, 4,6,7 whereas others have also reported associations with hemorrhagic stroke.…”

“…[2][3][4][5][6][7][8][9] Although a number of these studies have examined mortality and others have used hospital admissions as a proxy for incident cases, a few have used population case registers, which aim to capture all incident cases. 4,5 A number of these acute effects studies have reported associations between outdoor air pollutants and ischemic stoke, 4,6,7 whereas others have also reported associations with hemorrhagic stroke. 8,9 In contrast, although there is an increasing number of studies examining the effects of chronic exposure to outdoor air pollution on cardiovascular mortality using cohort study designs, 10 few have specifically examined stroke mortality.…”

Impact of Particulate Matter Exposition on the Risk of Ischemic Stroke: Epidemiologic Evidence and Putative Mechanisms

“…We have identified 18 studies, which fulfilled these criteria (Table 4). [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] ACUTE EFFECTS OF PARTICULATE MATTER EXPOSURE Although most studies on PM and cardiovascular diseases have been conducted in developed western countries, first impulses for epidemiologic research on IS came from South Korea and Taiwan. 15,22,25 An increase in PM by an interquartile range in Seoul was associated with a 3% higher IS mortality.…”