Short-term effect of air pollution exposure on COPD exacerbations: a time series study in Bogota, Colombia

Introduction: Air pollution poses a risk for people with Chronic Obstructive Pulmonary Disease (COPD). This study estimated the short-term effect of variations in air pollutant concentrations on exacerbations of COPD (COPD-E) in Bogotá, Colombia. Methods: We performed an ecological time series study from 2014 to 2021 to evaluate the short-term effect of fine particulate matter (PM_2.5), nitrogen dioxide (NO₂), and ozone (O₃) levels on COPD-E treated in the emergency and hospitalization services. Daily counts of patients with COPD-E discharge diagnoses were obtained from the National Health Information System, and daily measurements of PM_2.5, NO₂, and O₃ concentrations and meteorological data were obtained from air monitoring stations. A Generalized Additive Model was used with Distributed Lag Non-Linear Models to control for confounders. Results: An increase of 10 μg/m³ in PM_2.5 and O₃ was associated with increased COPD-E admissions (lagged 0-3 days) with Relative Risk (RR) of 1.04 (95%CI: 1.02 -1.07) and RR:1.03 (95%CI:1.01 – 1.04), respectively. During the rainy season and minimum temperature of the series, for every 10 μg/m³ increase in PM_2.5 concentration, COPD-E admissions (lagged 0-3 days) increased with RR 1.03 (95%CI: 1.01-1.06). A higher magnitude of association was observed in men (PM_2.5, 1.04 95%CI:1.01 – 1.06 and O₃, 1.04 95%CI:1.02 – 1.05, lag 0-7 days) than in women. Conclusions: A higher air pollution was associated with more COPD-E. These results highlight the importance of actions aimed at improving air quality.