title: Ambient air pollutants and acute case-fatality of cerebro-cardiovascular events: Takashima Stroke and AMI Registry, Japan (1988-2004).
abstract: BACKGROUND
  Apart from the conventional risk factors, cerebro-cardiovascular disease (CVD) are also reported to be associated with air pollution, thus lowering the level of exposure might contribute in prevention activities to reduce the associated adverse outcomes. Though few studies conducted in Japan have reported on the CVD mortality but none have explored the effect of air pollutant exposure on the acute case-fatality of CVD. We investigated the effects of air pollution exposure on acute case-fatality of stroke and acute myocardial infarction (AMI) in a setting where pollutant levels are rather low.
  
  
  METHODS
  We leveraged the data from the Takashima Stroke and AMI Registry, which covers a population of approximately 55,000 in Takashima County located in central Japan. The study period of 6,210 days (16 years, leap years also taken into account) were divided into quartiles of daily average pollutant concentration; suspended particulate matter (SPM), sulfur dioxide (SO(2)), nitrogen dioxide (NO(2)), and photochemical oxidants (Ox). The stroke and AMI events were categorized to corresponding quartiles based on the pollution levels of the onset day. To study the effects of air pollutants, we estimated the fatality rate ratio across quartiles of the pollutants where the lowest quartile served as the reference.
  
  
  RESULTS
  There were 307 (men: 153 and women: 154) fatal stroke cases within 28 days of onset among the 2,038 first ever stroke during 1988-2004. In the same period, there were 142 (men: 94 and women: 54) fatal AMI cases within 28 days of onset among the 429 first ever AMI events. The mean of the measured pollutant levels were as follows: SPM 26.9 µg/m(3), SO(2) 3.9 ppb, NO(2) 16.0 ppb, and Ox 28.4 ppb. Among the pollutants, higher levels of NO(2) showed increased fatality risk. In multi-pollutant model, the highest quartile of NO(2) was associated with 60% higher stroke case-fatality risk in comparison to lowest quartile of NO(2). In the fully adjusted model the fatality-rate ratio was 1.65 (95% CI 1.06-2.57). This association was more prominent among stroke subtype of cerebral infarction. Other pollutant levels did not show any association with stroke or AMI case-fatality.
  
  
  CONCLUSIONS
  We observed association between NO(2) levels, an index of traffic related air pollution, with the acute case-fatality of stroke, especially cerebral infarction in our study population. Further studies are needed in different regions to determine the association between ambient air pollutants and acute cardiovascular fatalities.
authors.affiliation: Department of Medicine, University of Calgary, Calgary, Alta., Canada. turin.chowdhury@ucalgary.ca
authors.forename: Tanvir Chowdhury
authors.initials: TC
authors.lastname: Turin
authors.forename: Yoshikuni
authors.initials: Y
authors.lastname: Kita
authors.forename: Nahid
authors.initials: N
authors.lastname: Rumana
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Kayo
authors.initials: K
authors.lastname: Ueda
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Takashima
authors.forename: Hideki
authors.initials: H
authors.lastname: Sugihara
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Morita
authors.forename: Masaharu
authors.initials: M
authors.lastname: Ichikawa
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Hirose
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nitta
authors.forename: Akira
authors.initials: A
authors.lastname: Okayama
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Miura
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Ueshima
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000393:Air Pollutants / Q000032:analysis* / Q000633:toxicity; D000397:Air Pollution / Q000009:adverse effects*; D002543:Cerebral Hemorrhage / Q000139:chemically induced / Q000209:etiology / Q000401:mortality; D002544:Cerebral Infarction / Q000139:chemically induced / Q000209:etiology / Q000401:mortality; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009203:Myocardial Infarction / Q000139:chemically induced / Q000209:etiology / Q000401:mortality*; D009585:Nitrogen Dioxide / Q000032:analysis / Q000633:toxicity; D010083:Oxidants, Photochemical / Q000032:analysis / Q000633:toxicity; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity; D012042:Registries / Q000706:statistics & numerical data*; D020521:Stroke / Q000139:chemically induced / Q000209:etiology / Q000401:mortality*; D013345:Subarachnoid Hemorrhage / Q000139:chemically induced / Q000209:etiology / Q000401:mortality; D013458:Sulfur Dioxide / Q000032:analysis / Q000633:toxicity; D001335:Vehicle Emissions / Q000633:toxicity
chemical_list: D000393:Air Pollutants; D010083:Oxidants, Photochemical; D052638:Particulate Matter; D001335:Vehicle Emissions; D013458:Sulfur Dioxide; D009585:Nitrogen Dioxide