title: Elemental carbon exposure at residence and survival after acute myocardial infarction.
abstract: BACKGROUND
  Particulate air pollution has been consistently related to cardiovascular mortality. Some evidence suggests that particulate matter may accelerate the atherosclerotic process. Effects of within-city variations of particulate air pollution on survival after an acute cardiovascular event have been little explored.
  
  
  METHODS
  We conducted a cohort study of hospital survivors of acute myocardial infarction (MI) from the Worcester, MA, metropolitan area to investigate the long-term effects of within-city variation in traffic-related air pollution on mortality. The study builds on an ongoing community-wide investigation examining changes over time in MI incidence and case-fatality rates. We included confirmed cases of MI in 1995, 1997, 1999, 2001, and 2003. Long-term survival status was ascertained through 2005. A validated spatiotemporal land use regression model for traffic-related air pollution was developed and annual averages of elemental carbon at residence estimated. The effect of estimated elemental carbon on the long-term mortality of patients discharged after MI was analyzed using a Cox proportional hazards model, controlling for a variety of demographic, medical history, and clinical variables.
  
  
  RESULTS
  Of the 3895 patients with validated MI, 44% died during follow-up. Exposure to estimated elemental carbon in the year of entry into the study was 0.44 microg/m on average. All-cause mortality increased by 15% (95% confidence interval = 0.03%-29%) per interquartile range increase in estimated yearly elemental carbon (0.24 microg/m) after the second year of survival. No association between traffic-related pollution and all-cause mortality was observed during the first 2 years of follow-up.
  
  
  CONCLUSIONS
  Chronic traffic-related particulate air pollution is associated with increased mortality in hospital survivors of acute MI after the second year of survival.
authors.affiliation: Department of Environmental Health, Boston, Harvard School of Public Health, Boston, MA, USA. klot@helmholtz-muenchen.de
authors.forename: Stephanie
authors.initials: S
authors.lastname: von Klot
authors.forename: Alexandros
authors.initials: A
authors.lastname: Gryparis
authors.forename: Cathryn
authors.initials: C
authors.lastname: Tonne
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Yanosky
authors.forename: Brent A
authors.initials: BA
authors.lastname: Coull
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Goldberg
authors.forename: Darleen
authors.initials: D
authors.lastname: Lessard
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Melly
authors.forename: Helen H
authors.initials: HH
authors.lastname: Suh
authors.forename: Joel
authors.initials: J
authors.lastname: Schwartz
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000009:adverse effects*; D002244:Carbon / Q000009:adverse effects*; D004781:Environmental Exposure / Q000032:analysis; D005260:Female; D006801:Humans; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality*; D016016:Proportional Hazards Models; D016019:Survival Analysis; D001335:Vehicle Emissions / Q000032:analysis / Q000506:poisoning
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions; D002244:Carbon