Ambient Pollution and Stroke Time to Clear the Air on Causal Mechanisms

Air pollution poses a substantial but potentially modifiable threat to global health. It preferentially affects the respiratory and cardiovascular systems, and therefore there is a growing interest in the effects of this environmental exposure in stroke.(1) Air pollution is a global issue, but it particularly affects low and middle-income countries with fast growing economies.(1) An estimated 16.9% of the roughly 15 million strokes per year worldwide can be attributed to air pollution.(1,2) Both short-(3) and long-term exposure to air pollution increase the risk for developing an ischemic stroke.(1) This association seems to primarily affect risk of strokes due to atherosclerosis, including large artery(4) and small vessel.(5) Air pollution might also acutely precipitate stroke, as suggested by daily incidence data.(6) Data suggest an association between short-term pollution and intracerebral hemorrhage(7) as well as a close temporal association between pollution and mortality after stroke.(3)