Fine Particulate Matter Associated with Increase in Hospital Admissions for Cardiovascular Diseases

Francesca Dominici, Ph.D.; Scott L. Zeger, Ph.D.; and Jonathan M. Samet, MD
Bloomberg School of Public Health, Johns Hopkins University
R01ES12054 and P30ES03819

Background: Research supported by NIEHS over the previous fifteen years has demonstrated links between cardiovascular disease and particulate matter air pollution. People with pre-existing conditions such as high blood pressure, previous heart disease, diabetes, respiratory disease, and high cholesterol have been shown to be especially vulnerable. This research has led to more stringent standards for particulate matter pollution in the U.S. and other countries. The revision of the National Ambient Air Quality Standard in 1997, created a new category of particulate matter less than 2.5 micrometers (PM2.5) in diameter. Sources of PM2.5 include motor vehicle emissions, coal-burning power plants, etc. Particles in this size range are much more likely than larger particles to lodge in the small airways and alveoli of the lungs. Subsequently, a nationwide monitoring system was established to measure this pollutant. Data on PM2.5, beginning in 1999, are now available for many parts of the U.S.

Advance: NIEHS grantees at the Johns Hopkins Bloomberg School of Public Health have determined that short-term exposure to PM2.5 significantly increases the risk for cardiovascular and respiratory disease among people over 65 years of age. The investigators linked PM2.5 data to hospital admissions for heart and vascular diseases, heart failure, chronic obstructive pulmonary disease, and respiratory infections in an epidemiologic study of over 11.5 million Medicare participants. The study results predict that for each 100 hospital admissions for heart failure, one extra admission will occur for each 10 micrometers per cubic meter increase in PM2.5. For example, during the study period 1999-2002, Cook County, Illinois had an average PM2.5 level of 16 micrometers per cubic meter of air and a high of 56. Therefore on days with the highest particulate matter pollution, the study predicts five additional hospitalizations per 100.

Implications: This study shows that exposure to PM2.5 at levels within the current standard is a risk factor for cardiovascular disease in elderly persons. Additional efforts need to be targeted towards identifying the sources of these particles and designing new strategies to prevent their release. Additional biomedical strategies include identifying the characteristics of fine particles responsible for these adverse effects so that new strategies can be developed to prevent or treat them.

Citation: 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. 2006 Mar 8;295(10):1127-34.