Particulate matter and exacerbations of chronic obstructive pulmonary disease: analysis of emergency department visits in a low-pollution area

Abstract

Objective. To evaluate the association between particulate matter concentration (PM10 and PM2.5) and the number of emergency department visits for exacerbation of chronic obstructive pulmonary disease (COPD) in a low-pollution area. Method. We conducted an ecological study based on emergency department visits for COPD exacerbations. A generalized additive model was used to estimate the relative risk and attributable fraction (AF), adjusting for weather variables. Pollution levels on the day of the visit and the 5 preceding days were considered to assess potential delayed effects of exposure. Results. A total of 2,045 patients with 5,233 emergency department visits were included. A total of 79.1% of the patients were men. The mean age was 79.5 years (SD, 10.1). The mean concentration of PM2.5 and PM10 was 11.5 µg/m³ and 17.3 µg/m³, respectively. Both emergency visits and particulate matter concentrations showed a seasonal pattern. A significant association was found with exposure occurring 3 days prior (lag-3), with a 5.8% increase in visits for every 10 µg/m³ increase in PM2.5 (AF 5.45%) and a 3.3% increase for PM10 (AF 3.15%). Men and patients older than 75 years showed greater sensitivity to exposure. The impact of particulate matter was more pronounced during the summer months. Conclusions. Exposure to PM2.5 and PM10 is associated with an increase in emergency department visits for COPD exacerbations, with a particular impact among men, patients older than 75 years, and during the summer season.