Long-term Exposure to PM_2.5 and Incidence of Acute Myocardial Infarction

Jaime Madrigano,^1,2,3 Itai Kloog,³ Robert Goldberg,⁴ Brent A. Coull,^3,5 Murray A. Mittleman,^6,7 and Joel Schwartz^3,7


¹The Earth Institute, and ²Mailman School of Public Health, Columbia University, New York, New York, USA; ³Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA; ⁴University of Massachusetts Medical School, Worcester, Massachusetts, USA; ⁵Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, USA; ⁶Cardiovascular Epidemiology Research Unit, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; ⁷Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA


Abstract

Background: A number of studies have shown associations between chronic exposure to particulate air pollution and increased mortality, particularly from cardiovascular disease, but fewer studies have examined the association between long-term exposure to fine particulate air pollution and specific cardiovascular events, such as acute myocardial infarction (AMI).


Objective: We examined how long-term exposure to area particulate matter affects the onset of AMI, and we distinguished between area and local pollutants.


Methods: Building on the Worcester Heart Attack Study, an ongoing community-wide investigation examining changes over time in myocardial infarction incidence in greater Worcester, Massachusetts, we conducted a case–control study of 4,467 confirmed cases of AMI diagnosed between 1995 and 2003 and 9,072 matched controls selected from Massachusetts resident lists. We used a prediction model based on satellite aerosol optical depth (AOD) measurements to generate both exposure to particulate matter ≤ 2.5 μm in diameter (PM_2.5) at the area level (10 × 10 km) and the local level (100 m) based on local land use variables. We then examined the association between area and local particulate pollution and occurrence of AMI.


Results: An interquartile range (IQR) increase in area PM_2.5 (0.59 μg/m³) was associated with a 16% increase in the odds of AMI (95% CI: 1.04, 1.29). An IQR increase in total PM_2.5 (area + local, 1.05 μg/m³) was weakly associated with a 4% increase in the odds of AMI (95% CI: 0.96, 1.11).


Conclusions: Residential exposure to PM_2.5 may best be represented by a combination of area and local PM_2.5, and it is important to consider spatial gradients within a single metropolitan area when examining the relationship between particulate matter exposure and cardiovascular events.


Key words: air pollution. 


Environ Health Perspect 121:192–196 (2013). http://dx.doi.org/10.1289/ehp.1205284 [Online 29 November 2012]


Address correspondence to J. Madrigano, Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722 West 168th St., 11th Floor, New York, New York 10032 USA. Telephone: (212) 305-3464. E-mail: jm3731@columbia.edu


We thank the participating hospitals in the Worcester, Massachusetts, metropolitan area whose cooperation made this study possible.


This work was supported by the National Institutes of Health (grant RO1 HL35434), and the U.S. Environmental Protection Agency (EPA; grant RD 83479801).


The contents of this article are solely the responsibility of the authors and do not necessarily represent the official views of the U.S. EPA. Further, the U.S. EPA does not endorse the purchase of any commercial products or services mentioned in the publication.


The authors declare they have no actual or potential competing financial interests.


Received 29 March 2012; Accepted 29 September 2012; Online 29 November 2012.