TY - JOUR
T1 - Airborne fine particles and risk of hospital admissions for understudied populations
T2 - Effects by urbanicity and short-term cumulative exposures in 708 U.S. Counties
AU - Bravo, Mercedes A.
AU - Ebisu, Keita
AU - Dominici, Francesca
AU - Wang, Yun
AU - Peng, Roger D.
AU - Bell, Michelle L.
N1 - Funding Information:
The research reported in this publication was supported by the National Institutes of Health under award numbers R01ES019560 (R.D.P., M.L.B.), R01ES026217, R01ES024332, R21ES024012, and P50MD010428, and with support from the Health Effects Institute (F.D., Y.W.). It was also developed under U.S. Environmental Protection Agency (EPA) grants 83479801 (M.L.B., K.E., F.D.), R833863 (M.L.B., K.E., M.A.B.) and Assistance Agreement no. 83587101, awarded by the U.S. EPA to Yale University (M.L.B., R.D.P.).
Publisher Copyright:
© 2017, Public Health Services, US Dept of Health and Human Services. All rights reserved.
PY - 2017/4
Y1 - 2017/4
N2 - Background: Evidence of health risks associated with ambient airborne fine particles in nonurban populations is extremely limited. Objective: We estimated the risk of hospitalization associated with short-term exposures to particulate matter with an aerodynamic diameter < 2.5 μm (PM2.5) in urban and nonurban counties with population ≥ 50,000. Methods: We utilized a database of daily cardiovascular- and respiratory-related hospitalization rates constructed from Medicare National Claims History files (2002–2006), including 28 million Medicare beneficiaries in 708 counties. Daily PM2.5 exposures were estimated using the Community Multiscale Air Quality (CMAQ) downscaler. We used time-series analysis of hospitalization rates and PM2.5 to evaluate associations between PM2.5 levels and hospitalization risk in single-pollutant models. Results: We observed an association between cardiovascular hospitalizations and same-day PM2.5 with higher risk in urban counties: 0.35% [95% posterior interval (PI): –0.71%, 1.41%] and 0.98% (95% PI: 0.73%, 1.23%) increases in hospitalization risk per 10-μg/m3 increment in PM2.5 were observed in the least-urban and most-urban counties, respectively. The largest association for respiratory hospitalizations, a 2.57% (95% PI: 0.87%, 4.30%) increase per 10-μg/m3 increase in PM2.5, was observed in the least-urban counties; in the most-urban counties, a 1.13% (0.73%, 1.54%) increase was observed. Effect estimates for cardiovascular hospitalizations were highest for smaller lag times, whereas effect estimates for respiratory hospitalizations increased as more days of exposure were included. Conclusion: In nonurban counties with population ≥ 50,000, exposure to PM2.5 is associated with increased risk for respiratory hospitalizations; in urban counties, exposure is associated with increased risk of cardiovascular hospitalizations. Effect estimates based on a single day of exposure may underestimate true effects for respiratory hospitalizations.
AB - Background: Evidence of health risks associated with ambient airborne fine particles in nonurban populations is extremely limited. Objective: We estimated the risk of hospitalization associated with short-term exposures to particulate matter with an aerodynamic diameter < 2.5 μm (PM2.5) in urban and nonurban counties with population ≥ 50,000. Methods: We utilized a database of daily cardiovascular- and respiratory-related hospitalization rates constructed from Medicare National Claims History files (2002–2006), including 28 million Medicare beneficiaries in 708 counties. Daily PM2.5 exposures were estimated using the Community Multiscale Air Quality (CMAQ) downscaler. We used time-series analysis of hospitalization rates and PM2.5 to evaluate associations between PM2.5 levels and hospitalization risk in single-pollutant models. Results: We observed an association between cardiovascular hospitalizations and same-day PM2.5 with higher risk in urban counties: 0.35% [95% posterior interval (PI): –0.71%, 1.41%] and 0.98% (95% PI: 0.73%, 1.23%) increases in hospitalization risk per 10-μg/m3 increment in PM2.5 were observed in the least-urban and most-urban counties, respectively. The largest association for respiratory hospitalizations, a 2.57% (95% PI: 0.87%, 4.30%) increase per 10-μg/m3 increase in PM2.5, was observed in the least-urban counties; in the most-urban counties, a 1.13% (0.73%, 1.54%) increase was observed. Effect estimates for cardiovascular hospitalizations were highest for smaller lag times, whereas effect estimates for respiratory hospitalizations increased as more days of exposure were included. Conclusion: In nonurban counties with population ≥ 50,000, exposure to PM2.5 is associated with increased risk for respiratory hospitalizations; in urban counties, exposure is associated with increased risk of cardiovascular hospitalizations. Effect estimates based on a single day of exposure may underestimate true effects for respiratory hospitalizations.
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U2 - 10.1289/EHP257
DO - 10.1289/EHP257
M3 - Article
C2 - 27649448
AN - SCOPUS:85016786274
SN - 0091-6765
VL - 125
SP - 594
EP - 601
JO - Environmental health perspectives
JF - Environmental health perspectives
IS - 4
ER -