Association between exposure to air pollution and mortality in patients with idiopathic pulmonary fibrosis

Abstract

Introduction: The prognosis of Idiopathic pulmonary fibrosis (IPF) is influenced by multiple factors including exposure to air pollution. Aims: To assess the effects of individual exposure to particulate matter with aerodynamic diameter ≤10 μm (PM10), and nitrogen dioxide (NO2) on mortality in IPF patients in South Korea between 1995 and 2016. Methods: Total 1142 patients (mean age: 65.6 years, male: 80.5%) with IPF were included in our study. Individual exposures were assessed based on annual-average concentrations of PM10 and NO2 of the patients’ address in 2006, which was predicted by an air pollution prediction model. Results: Median follow-up period was 3.8 years and 789 patients (69.1%) died. The mean PM10 and NO2 concentrations were 55.9 ± 5.3 μg/m3 and 22.5 ± 9.1 ppb, respectively. In a univariate Cox model, PM10 (hazard ratio [HR], 1.000 for 10 μg/m3 increase; p=0.962) and NO2 (HR, 0.886 for 10 ppb increase; p=0.561) were not associated with mortality; however, age, body mass index, forced vital capacity and diffusing capacity for carbon monoxide were significant prognostic factors. When adjusted by age, sex, and FVC, PM10 (HR, 0.932; p=0.305) and NO2 (HR, 0.961; p=0.325) were also not associated with mortality. Conclusions: Contrast to previous reports, the exposure to PM10 and NO2 was not associated with mortality in Korean patients with IPF.