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Association of Short-Term Increases in Ambient Fine Particulate Matter With Hospitalization for Asthma or COPD During
Benjamin D Horne1, Mary M Johnson1, Denitza P Blagev1
1Intermountain Medical Center Heart Institute (B. D. H., K. U. K., D. B., and T. L. B.), Salt Lake City, UT; the Division of Cardiovascular Medicine, Department of Medicine (B. D. H. and F. H.) and the Cardiovascular Institute (B. D. H. and F. H.), Stanford University, Stanford, CA; the Department of Environmental Health (M. M. J. and K. C. N.), Harvard T.H. Chan School of Public Health, Boston, MA; the Division of Pulmonary and Critical Care Medicine (D. B. P.), Department of Internal Medicine, Intermountain Health, Salt Lake City, UT; the Division of Cardiology (K. U. K.), Department of Internal Medicine, University of Utah, Salt Lake City, UT; the Wellness & Nutrition (E. A. J.), Intermountain Health, Salt Lake City, UT; and the Department of Family and Preventive Medicine (E. A. J.), University of Utah, Salt Lake City, UT.
Background:
Short-term increases in air pollution are associated with poor asthma and COPD outcomes. Short-term elevations in fine particulate matter (PM2.5) due to wildfire smoke are becoming more common.
Research Question:
Are short-term increases in PM2.5 and ozone in wildfire season and in winter inversion season associated with a composite of emergency or inpatient hospitalization for asthma and COPD?
Study Design And Methods:
Case-crossover analyses evaluated 63,976 and 18,514 patients hospitalized for primary discharge diagnoses of asthma and COPD, respectively, between January 1999 and March 2022. Patients resided on Utah's Wasatch Front where PM2.5 and ozone were measured by Environmental Protection Agency-based monitors. ORs were calculated using Poisson regression adjusted for weather variables.
Results:
Asthma risk increased on the same day that PM2.5 increased during wildfire season (OR, 1.057 per + 10 μg/m3; 95% CI, 1.019-1.097; P = .003) and winter inversions (OR, 1.023 per +10 μg/m3; 95% CI, 1.010-1.037; P = .0004). Risk decreased after 1 week, but during wildfire season risk rebounded at a 4-week lag (OR, 1.098 per +10 μg/m3; 95% CI, 1.033-1.167). Asthma risk for adults during wildfire season was highest in the first 3 days after PM2.5 increases, but for children, the highest risk was delayed by 3 to 4 weeks. PM2.5 exposure was weakly associated with COPD hospitalization. Ozone exposure was not associated with elevated risks.
Interpretation:
In a large urban population, short-term increases in PM2.5 during wildfire season were associated with asthma hospitalization, and the effect sizes were greater than for PM2.5 during inversion season.
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