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Association Between Air Pollution Exposure and Risk of Hemorrhagic Stroke: A Systematic Review and Meta-analysis
Syed Asad Irfan1, Kleiton Strobl2, Khubaib Wariach3
1Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
The Canadian Journal of Cardiology
|May 26, 2026
Summary
Short-term exposure to nitrogen dioxide (NO2) and carbon monoxide (CO) air pollutants significantly increases hemorrhagic stroke risk. These findings aid in developing public health strategies to reduce cerebrovascular disease burden.
Area of Science:
- Environmental Health
- Epidemiology
- Cardiovascular Research
Background:
- Air pollution is linked to various health issues.
- The connection between short-term air pollution and hemorrhagic stroke requires further investigation.
- Hemorrhagic stroke is a major global health concern with high mortality.
Purpose of the Study:
- To evaluate the association between short-term exposure to specific air pollutants and the risk of hemorrhagic stroke.
- To synthesize current evidence through a meta-analysis.
Main Methods:
- Systematic literature search across Embase, Ovid Medline, Web of Science, and PubMed.
- Included time series, case-crossover, and cohort studies on hemorrhagic stroke and air pollution (PM2.5, PM10, NO2, SO2, O3, CO).
- Meta-analysis of risk outcomes using inverse variance and random effects models.
Main Results:
- 31 studies from 2,435 identified were included in the meta-analysis.
- A significant increase in hemorrhagic stroke risk was observed per 10 μg/m³ increase in NO2 exposure (RR = 1.0142).
- A significant increase in hemorrhagic stroke risk was observed per 10 μg/m³ increase in CO exposure (OR = 1.0008).
Conclusions:
- Exposure to NO2 and CO are statistically associated with increased hemorrhagic stroke risk.
- Findings can inform preventative measures and public health policies.
- Reducing exposure to these pollutants may decrease the incidence of cardiovascular and cerebrovascular diseases.
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