Associations of particulate matter with stroke mortality: a multicity study in Japan.

Abstract

Evidence linking short-term exposure to outdoor air pollution with hemorrhagic stroke is inconclusive. We evaluated the effects of suspended particulate matter (SPM) on cardiovascular disease mortality, focusing on types of stroke, from March 2005 to December 2010, in five selected prefectures in western Japan. A multicity time-series analysis was used, and Asian dust was adjusted in the models. Even after adjusting for Asian dust, the same-day SPM was positively associated with several types of stroke mortality. Following a 10-μg/m increase in SPM, rate ratios were 1.014 (90% confidence interval [CI]: 1.002 to 1.026) for stroke, 1.030 (90% CI: 1.004 to 1.056) for intracerebral hemorrhage, and 1.016 (90% CI: 1.003 to 1.030) for ischemic stroke mortality. Short-term exposure to outdoor air pollution may increase the risks of hemorrhagic stroke as well as ischemic stroke mortality.