The impact of air pollutants and meteorological factors on chronic obstructive pulmonary disease exacerbations: a nationwide study

Abstract

Rationale: Chronic obstructive lung disease (COPD) is a chronic progressive disease. Although smoking is the most important risk factor, 30% of patients with COPD are never-smokers, and environmental agents are also influential. The effects of air pollutants and meteorological factors on COPD exacerbations have not been studied extensively. Objectives: We aimed to investigate the air pollutants and meteorological factors that impact the incidence of COPD exacerbations. Methods: We obtained clinical data of COPD exacerbation cases from The National Health Insurance Service and merged it with 24-hour average values of air pollutants and meteorological factors from national databases. Patients who reside in eight metropolitan cities, where observatory stations are densely located, were selected for analysis. Results: In 1,404,505 patients with COPD between 2013 and 2018, 15,282 COPD exacerbations leading to hospitalization or emergency room visits were identified. Among the various air pollutants and meteorological factors, particulate matter ？2.5 μm in aerodynamic diameter (PM2.5), particulate matter ？10 μm in aerodynamic diameter (PM10), NO2, SO2, CO, O3, average temperature, and diurnal temperature range (DTR) were associated with COPD exacerbations. Generalized additive mode model analysis with cubic splines showed an inverted U-shaped relationship with PM2.5, PM10, CO, NO2, SO2, O3, DTR, and humidity, whereas it displayed a U-shaped pattern with the average temperature. Distinct patterns were found from 2015-2016 to 2017-2018. Conclusions: PM2.5, PM10, CO, NO2, O3, SO2, average temperature, humidity, and DTR affected the incidence of COPD exacerbations in various patterns, up to 10 lag days.