Abstract
Background and Purpose: Outdoor air pollution represents a potentially modifiable risk factor for stroke. We examined the link between ambient pollution and mortality up to 5 years post-stroke, especially for pollutants associated with vehicle exhaust.
Methods: Data from the South London Stroke Register, a population-based register covering an urban, multi-ethnic population was used. Hazard ratios (HR) for a one interquartile range increase in particulate matter <2.5µm diameter (PM2.5) and <10µm (PM10) were estimated post-stroke using Cox regression, overall and broken down into exhaust and non-exhaust components. Analysis was stratified for ischaemic and haemorrhagic strokes and was further broken down by Oxford Community Stroke Project classification.
Results: The hazard of death associated with PM2.5 up to 5 years after stroke was significantly elevated (p’s=0.006) for all strokes (HR=1.28, 95%CI 1.08-1.53) and ischaemic strokes (HR=1.32, 95%CI 1.08-1.62). Within ischaemic subtypes, PM2.5 pollution increased mortality risk for total anterior circulation infarcts (TACI) by two-fold (HR=2.01, 95%CI 1.17-3.48, p=0.012) and by 78% for lacunar infarcts (LACI) (HR=1.78, 95%CI 1.18-2.66, p=0.006). PM10 pollution was associated with 45% increased mortality risk for LACI strokes (HR=1.45, 95%CI 1.06-2.00, p=0.022). Separating PM2.5 and PM10 into exhaust and non-exhaust components did not show increased mortality.
Conclusions: Exposure to certain outdoor particulate matter pollution, particularly particulate matter <2.5µm diameter (PM2.5), increased morality risk post-stroke up to 5 years after the initial stroke.
Methods: Data from the South London Stroke Register, a population-based register covering an urban, multi-ethnic population was used. Hazard ratios (HR) for a one interquartile range increase in particulate matter <2.5µm diameter (PM2.5) and <10µm (PM10) were estimated post-stroke using Cox regression, overall and broken down into exhaust and non-exhaust components. Analysis was stratified for ischaemic and haemorrhagic strokes and was further broken down by Oxford Community Stroke Project classification.
Results: The hazard of death associated with PM2.5 up to 5 years after stroke was significantly elevated (p’s=0.006) for all strokes (HR=1.28, 95%CI 1.08-1.53) and ischaemic strokes (HR=1.32, 95%CI 1.08-1.62). Within ischaemic subtypes, PM2.5 pollution increased mortality risk for total anterior circulation infarcts (TACI) by two-fold (HR=2.01, 95%CI 1.17-3.48, p=0.012) and by 78% for lacunar infarcts (LACI) (HR=1.78, 95%CI 1.18-2.66, p=0.006). PM10 pollution was associated with 45% increased mortality risk for LACI strokes (HR=1.45, 95%CI 1.06-2.00, p=0.022). Separating PM2.5 and PM10 into exhaust and non-exhaust components did not show increased mortality.
Conclusions: Exposure to certain outdoor particulate matter pollution, particularly particulate matter <2.5µm diameter (PM2.5), increased morality risk post-stroke up to 5 years after the initial stroke.
Original language | English |
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Journal | Stroke |
Publication status | Accepted/In press - Sept 2016 |