Individual Exposure to Ambient PM2.5 and Hospital Admissions for COPD in 110 Hospitals: A Case-Crossover Study in Guangzhou, China

Abstract Few studies have evaluated the short-term association between hospital admissions and individual exposure to ambient particulate matter (PM2.5). Particularly, no studies focused on hospital admissions for chronic obstructive pulmonary disease (COPD) at individual level. We assessed the short-term effects of PM2.5 on hospitalization admissions for COPD in Guangzhou, China, during 2014–2015, based on satellite-derived estimates of ambient PM2.5 concentrations at 1-km resolution near the residential address as individual-level exposure for each patient. 40,002 patients with COPD admitted to 110 hospitals were included in this study. A time-stratified case-crossover design with conditional logistic regression models was applied to assess the effects of PM2.5 based on 1-km grid data of aerosol optical depth provided by National Aeronautics and Space Administration on hospital admissions for COPD. Further, we performed stratified analyses by individual demographic characteristics and season of hospital admission. 10 µg/m3 increase in individual-level PM2.5 was associated with an increase of 1.6% (95% confidence interval [CI]: 0.6%, 2.7%) in hospitalization for COPD at lag of 0–5 days. The impact of PM2.5 on hospitalization for COPD was greater significantly in male and patients admitted in summer and accordingly the impacts may be exacerbated in the context of global warming. Our study strengthened the evidence for the adverse effect of PM2.5 based on satellite-based individual-level exposure data.