2005 Progress Report: Chronic and Acute Exposure to Ambient Fine Particulate Matter and Other Air Pollutants: National Cohort Studies of Mortality and Morbidity

EPA Grant Number: R830548
Title: Chronic and Acute Exposure to Ambient Fine Particulate Matter and Other Air Pollutants: National Cohort Studies of Mortality and Morbidity
Investigators: Samet, Jonathan M. , Dominici, Francesca , Geyh, Alison , McDermott, Aidan , Parent, Stephen T. , Wyant, Timothy , Zeger, Scott L.
Current Investigators: Samet, Jonathan M.
Institution: The Johns Hopkins University , Decipher , Health Systems Innovations
EPA Project Officer: Chung, Serena
Project Period: February 1, 2003 through January 31, 2006 (Extended to January 31, 2007)
Project Period Covered by this Report: February 1, 2005 through January 31, 2006
Project Amount: $1,033,646
RFA: Epidemiologic Research on Health Effects of Long-Term Exposure to Ambient Particulate Matter and Other Air Pollutants (2002) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Health Effects , Particulate Matter , Air


The objective of the research project is to address a key uncertainty in the evidence on the effects of particulate matter (PM) on public health:  the effects of longer term exposure to airborne PM, including PM2.5, on morbidity and mortality.  By using large, existing cohorts established by federal agencies, we will:  (1) test the hypothesis that long-term exposure to PM increases mortality and morbidity; (2) explore whether any effect of PM varies with levels of other pollutants; and (3) compare risks of exposure to PM in persons with and without underlying heart and lung disease.  As the large cohorts include daily data, we also will apply methods for time-series analysis to compare the effect of PM on time scales ranging from daily to yearly.  In addition, we will explore spatial variation of the effects of PM and other pollutants.  We also will establish a protocol for ongoing use of these studies for tracking the public health risks of air pollution.

The focus of analysis will be the longitudinal data in the National Medicare Cohort, comprising over 27 million Medicare participants living within 10 miles of a PM2.5 monitor and followed for hospitalization and death.  For a 5 percent sample, outpatient visits are available. We have data for 1999-2002, with approximately 800,000 deaths annually.  We will use hospitalization data to construct comorbidity measures.  A separate smaller survey, the Medicare Current Beneficiary Survey, provides information on a large number of potential confounding factors.  We will also explore the use of the Veterans Health Study Cohort, which includes 900,000 persons.  Data on hospitalization and mortality from these cohorts will be combined with weather data and the air monitoring data routinely collected by the U.S. Environmental Protection Agency.  Over the 3 years of the project, we will obtain data and create the analytic data base, address methodological issues related to imputation of potential confounding factors, and estimate the acute and chronic effects of PM2.5 and other pollutants on morbidity and mortality, including characterizing effects on differing timescales and regions of the country.

We have identified epidemiologic cohorts that can provide reasonably precise estimates of the health risks posed by PM2.5 and other pollutants.  The cohorts will provide sufficient events to directly address risks of PM2.5 without using surrogate indicators.  The data will offer insights into cardiac and respiratory comorbidity as a determinant of susceptibility and into the differing magnitudes of risks found in the time-series and cohort studies of PM.  The findings will advance understanding of the public health consequences of air pollution and support the development of more certain risk models for air pollution and health.

Progress Summary:

During Year 3 of the project, an analysis of risk for hospitalization among Medicare participants in association with PM2.5 concentration was completed.  Our findings indicate that there was a short-term increase in hospital admission rates associated with PM2.5 for all of the health outcomes except injuries.  The largest association was for heart failure, for which there was a 1.28 percent (95% confidence interval, 0.78%-1.78%) increase in risk per 10 µg/m3 increase in same-day PM2.5.  Cardiovascular risks tended to be higher in counties located in the Eastern region of the United States, which included the Northeast, the Southeast, the Midwest, and the South.

A separate analysis addressed the longer term risk of PM2.5.  Mortality rates for the 3-year interval, 2000-2002, were examined in relationship to average values for PM2.5 for the counties over the same period (Table 1).  The analysis provides strong independent evidence that mortality is higher in counties with higher PM2.5.  We found that a city with 10 µg/m3 higher long-term average PM2.5 has 7.6 percent higher (95% CI: 4.4 to 10.8% higher) mortality than a city with comparable age and gender distribution.  Geographic heterogeneity was noted with much lower risk in cities along the West Coast.

Table 1.  Annual Reduction in Admissions Attributable to a 10 µg/m3 Reduction in the Daily PM2.5 Level for the 204 Counties in 2002*

Cause-specific hospital admissions

Annual number of admissions

Annual reduction in admissions (95% CI)*

Cerebrovascular disease


1836 (680, 2992)

Peripheral vascular disease


602 (-42, 1254)

Ischemic heart disease


1523 (69, 2976)

Heart rhythm


967 (-17, 1951)

Heart failure


3156 (1923, 4389)



990 (196, 1785)

Respiratory infection


2085 (929, 3241)

* per 10 mg/m3 reduction in PM2.5.

Future Activities:

During Year 4, a major focus will be carrying out time-series analyses within medically defined groups of susceptible individuals.  We will use hospitalization to indicate the occurrence of an event, e.g., myocardial infarction, and track risk in the period following the event.  The proposed risk of susceptible subgroups is included in Table 1.  One key indicator of susceptibility will be time since event.

Journal Articles on this Report : 1 Displayed | Download in RIS Format

Other project views: All 12 publications 12 publications in selected types All 12 journal articles
Type Citation Project Document Sources
Journal Article Dominici F, Peng RD, Bell ML, Pham L, McDermott A, Zeger SL, Samet JM. Fine particulate air pollution and hospital admission for cardiovascular and respiratory diseases. JAMA-Journal of the American Medical Association 2006;295(10):1127-1134. R830548 (2005)
R832417 (Final)
R832417C001 (2006)
R832417C001 (2007)
R832417C001 (2008)
R832417C001 (2009)
R832417C001 (Final)
  • Full-text from PubMed
  • Abstract from PubMed
  • Associated PubMed link
  • Full-text: JAMA-Full Text HTML
  • Abstract: JAMA-Abstract
  • Supplemental Keywords:

    ambient air, health effects, epidemiology,, RFA, Health, Scientific Discipline, PHYSICAL ASPECTS, Air, HUMAN HEALTH, particulate matter, air toxics, Environmental Chemistry, Health Risk Assessment, Exposure, Epidemiology, Risk Assessments, Susceptibility/Sensitive Population/Genetic Susceptibility, Physical Processes, copollutant exposures, sensitive populations, atmospheric particulate matter, airway epithelial cells, cardiopulmonary responses, fine particles, PM 2.5, long term exposure, inhaled pollutants, acute cardiovascular effects, acute lung injury, morbidity, air pollution, susceptible subpopulations, cardiac arrest, chronic health effects, lung inflammation, time series analysis, particulate exposure, National Cohort Studies, cardiopulmonary response, human exposure, Acute health effects, inhaled, human susceptibility, cardiotoxicity, cardiopulmonary, mortality, concentrated particulate matter, air contaminant exposure, air quality, environmental hazard exposures, toxics, airborne urban contaminants, cardiovascular disease, acute exposure

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    Progress and Final Reports:

    Original Abstract
  • 2003 Progress Report
  • 2004 Progress Report
  • Final Report