Elemental carbon exposure at residence and survival after acute myocardial infarction.
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.
von Klot
Stephanie
S
Department of Environmental Health, Boston, Harvard School of Public Health, Boston, MA, USA. klot@helmholtz-muenchen.de
Gryparis
Alexandros
A
Tonne
Cathryn
C
Yanosky
Jeffrey
J
Coull
Brent A
BA
Goldberg
Robert J
RJ
Lessard
Darleen
D
Melly
Steven J
SJ
Suh
Helen H
HH
Schwartz
Joel
J
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
D000393:Air Pollutants; D001335:Vehicle Emissions; D002244:Carbon