title: Ambient fine particulate air pollution triggers ST-elevation myocardial infarction, but not non-ST elevation myocardial infarction: a case-crossover study.
abstract: BACKGROUND
  We and others have shown that increases in particulate air pollutant (PM) concentrations in the previous hours and days have been associated with increased risks of myocardial infarction, but little is known about the relationships between air pollution and specific subsets of myocardial infarction, such as ST-elevation myocardial infarction (STEMI) and non ST-elevation myocardial infarction (NSTEMI).
  
  
  METHODS
  Using data from acute coronary syndrome patients with STEMI (n = 338) and NSTEMI (n = 339) and case-crossover methods, we estimated the risk of STEMI and NSTEMI associated with increased ambient fine particle (<2.5 um) concentrations, ultrafine particle (10-100 nm) number concentrations, and accumulation mode particle (100-500 nm) number concentrations in the previous few hours and days.
  
  
  RESULTS
  We found a significant 18% increase in the risk of STEMI associated with each 7.1 μg/m³ increase in PM₂.₅ concentration in the previous hour prior to acute coronary syndrome onset, with smaller, non-significantly increased risks associated with increased fine particle concentrations in the previous 3, 12, and 24 hours. We found no pattern with NSTEMI. Estimates of the risk of STEMI associated with interquartile range increases in ultrafine particle and accumulation mode particle number concentrations in the previous 1 to 96 hours were all greater than 1.0, but not statistically significant. Patients with pre-existing hypertension had a significantly greater risk of STEMI associated with increased fine particle concentration in the previous hour than patients without hypertension.
  
  
  CONCLUSIONS
  Increased fine particle concentrations in the hour prior to acute coronary syndrome onset were associated with an increased risk of STEMI, but not NSTEMI. Patients with pre-existing hypertension and other cardiovascular disease appeared particularly susceptible. Further investigation into mechanisms by which PM can preferentially trigger STEMI over NSTEMI within this rapid time scale is needed.
authors.forename: Blake
authors.initials: B
authors.lastname: Gardner
authors.forename: Frederick
authors.initials: F
authors.lastname: Ling
authors.forename: Philip K
authors.initials: PK
authors.lastname: Hopke
authors.forename: Mark W
authors.initials: MW
authors.lastname: Frampton
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Utell
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zareba
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Cameron
authors.forename: David
authors.initials: D
authors.lastname: Chalupa
authors.forename: Cathleen
authors.initials: C
authors.lastname: Kane
authors.forename: Suresh
authors.initials: S
authors.lastname: Kulandhaisamy
authors.forename: Michael C
authors.initials: MC
authors.lastname: Topf
authors.affiliation: Department of Public Health Sciences, University of Rochester School of Medicine and Dentistry, 265 Crittenden Boulevard, CU 420644, Rochester, NY, USA. david_rich@urmc.rochester.edu.
authors.forename: David Q
authors.initials: DQ
authors.lastname: Rich
mesh_terms: D054058:Acute Coronary Syndrome / Q000139:chemically induced / Q000473:pathology; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000633:toxicity*; D015992:Body Mass Index; D016022:Case-Control Studies; D016001:Confidence Intervals; D018592:Cross-Over Studies; D003627:Data Interpretation, Statistical; D004562:Electrocardiography / Q000187:drug effects*; D005006:Ethnicity; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000139:chemically induced* / Q000473:pathology; D009518:New York; D052638:Particulate Matter / Q000633:toxicity*; D011446:Prospective Studies; D012107:Research Design; D013318:Stroke Volume; D016896:Treatment Outcome; D014887:Weather
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter