title: Associations of outdoor air pollution with hemorrhagic stroke mortality.
abstract: OBJECTIVE
  Evidence linking short-term exposure to outdoor air pollution with hemorrhagic stroke is inconsistent.
  
  
  METHODS
  We evaluated the associations between outdoor air pollution and specific types of stroke in Tokyo, Japan, from April 2003 to December 2008. We obtained daily counts of stroke mortality (n = 41,440) and concentrations of nitrogen dioxide as well as particles less than 2.5 μm in diameter. Time-series analysis was employed.
  
  
  RESULTS
  Although same-day air pollutants were positively associated with ischemic stroke and intracerebral hemorrhage mortality, both air pollutants were more strongly associated with subarachnoid hemorrhage mortality: rate ratio was 1.041 (95% confidence interval: 1.011-1.072) for each 10 μg/m3 increase in the previous-day particles less than 2.5 μm.
  
  
  CONCLUSIONS
  This study suggests that short-term exposure to outdoor air pollution increases the risks of hemorrhagic stroke mortality as well as ischemic stroke mortality.
authors.affiliation: Department of Epidemiology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan. yorichan@md.okayama-u.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Yorifuji
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kawachi
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Doi
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects; D000397:Air Pollution / Q000009:adverse effects* / Q000706:statistics & numerical data*; D002543:Cerebral Hemorrhage / Q000401:mortality; D004781:Environmental Exposure / Q000706:statistics & numerical data; D006801:Humans; D009585:Nitrogen Dioxide / Q000009:adverse effects; D052638:Particulate Matter / Q000009:adverse effects; D012307:Risk Factors; D020521:Stroke / Q000401:mortality*; D013345:Subarachnoid Hemorrhage / Q000401:mortality; D014041:Tokyo / Q000453:epidemiology
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D009585:Nitrogen Dioxide