Fine particulate air pollution and hospital admission for cardiovascular and respiratory diseases.
BACKGROUND
Evidence on the health risks associated with short-term exposure to fine particles (particulate matter < or =2.5 microm in aerodynamic diameter [PM2.5]) is limited. Results from the new national monitoring network for PM2.5 make possible systematic research on health risks at national and regional scales.


OBJECTIVE
To estimate risks of cardiovascular and respiratory hospital admissions associated with short-term exposure to PM2.5 for Medicare enrollees and to explore heterogeneity of the variation of risks across regions.


METHODS
A national database comprising daily time-series data daily for 1999 through 2002 on hospital admission rates (constructed from the Medicare National Claims History Files) for cardiovascular and respiratory outcomes and injuries, ambient PM2.5 levels, and temperature and dew-point temperature for 204 US urban counties (population >200,000) with 11.5 million Medicare enrollees (aged >65 years) living an average of 5.9 miles from a PM2.5 monitor.


METHODS
Daily counts of county-wide hospital admissions for primary diagnosis of cerebrovascular, peripheral, and ischemic heart diseases, heart rhythm, heart failure, chronic obstructive pulmonary disease, and respiratory infection, and injuries as a control outcome.


RESULTS
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, which had a 1.28% (95% confidence interval, 0.78%-1.78%) increase in risk per 10-microg/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.


CONCLUSIONS
Short-term exposure to PM2.5 increases the risk for hospital admission for cardiovascular and respiratory diseases.
Dominici
Francesca
F
Department of Biostatistics, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Md 21205, USA. fdominic@jhsph.edu
Peng
Roger D
RD
Bell
Michelle L
ML
Pham
Luu
L
McDermott
Aidan
A
Zeger
Scott L
SL
Samet
Jonathan M
JM
D000368:Aged; D000393:Air Pollutants; D000397:Air Pollution / Q000009:adverse effects / Q000706:statistics & numerical data*; D001499:Bayes Theorem; D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000209:etiology; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D006278:Medicare; D015233:Models, Statistical; D010316:Particle Size; D012140:Respiratory Tract Diseases / Q000453:epidemiology* / Q000209:etiology; D012306:Risk; D014481:United States / Q000453:epidemiology; D014505:Urban Population / Q000706:statistics & numerical data
D000393:Air Pollutants