title: Ethnic differences in ambient air pollution and risk of acute ischemic stroke.
abstract: OBJECTIVE
  To investigate the association between short-term changes in ambient pollution (particulate matter <2.5 μm in aerodynamic diameter (PM2.5) and ozone (O3)) and the risk of ischemic stroke among individuals living in a bi-ethnic community and whether this association is modified by ethnicity.
  
  
  METHODS
  We identified incident ischemic stroke cases from the population-based Brain Attack Surveillance in Corpus Christi (BASIC) project between 2000 and 2012. Associations between PM2.5 (mean 24-h) and O3 (maximal 8-h) levels, measured on the same-day and lags of 1-3 days, and odds of ischemic stroke were assessed using a time-stratified case-crossover design and modeled using conditional logistic regression. We explored race/ethnicity (Mexican American versus non-Hispanic white) as a modifier by including interaction terms in the models.
  
  
  RESULTS
  There were 2948 ischemic strokes with median age 71 years (IQR: 59-80). We observed no overall associations between the air pollutants and odds of ischemic stroke at any lag. When stratified by ethnicity, higher O3 was consistently associated with greater odds of ischemic stroke for non-Hispanic whites, but not for Mexican Americans. Higher PM2.5 was generally associated with lower odds of ischemic stroke for non-Hispanic whites but modestly greater odds for Mexican Americans.
  
  
  CONCLUSIONS
  Ethnic differences in the associations between ischemic stroke and short-term exposures to O3 and PM2.5 were suggested indicating that further study in diverse populations may be warranted.
authors.affiliation: Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, United States. Electronic address: wingjeff@umich.edu.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Wing
authors.affiliation: Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, United States.
authors.forename: Sara D
authors.initials: SD
authors.lastname: Adar
authors.affiliation: Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, United States.
authors.forename: Brisa N
authors.initials: BN
authors.lastname: Sánchez
authors.affiliation: Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, United States; Department of Neurology, Stroke Program, University of Michigan, Ann Arbor, United States.
authors.forename: Lewis B
authors.initials: LB
authors.lastname: Morgenstern
authors.affiliation: Department of Neurology, Stroke Program, University of Michigan, Ann Arbor, United States.
authors.forename: Melinda A
authors.initials: MA
authors.lastname: Smith
authors.affiliation: Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, United States; Department of Neurology, Stroke Program, University of Michigan, Ann Arbor, United States.
authors.forename: Lynda D
authors.initials: LD
authors.lastname: Lisabeth
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000032:analysis* / Q000633:toxicity; D002545:Brain Ischemia / Q000453:epidemiology / Q000208:ethnology / Q000209:etiology*; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D008297:Male; D017058:Mexican Americans / Q000706:statistics & numerical data*; D008875:Middle Aged; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis* / Q000633:toxicity; D020521:Stroke / Q000453:epidemiology / Q000208:ethnology / Q000209:etiology*; D013781:Texas / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data*
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter
keywords: Air pollution; Ethnicity; Ischemic stroke; Ozone; PM(2.5)