Long-term personal air pollution exposure and risk for acute exacerbation of idiopathic pulmonary fibrosis

Abstract

Background: Urban air pollution is involved in the progress of idiopathic pulmonary fibrosis (IPF). Its potential role on the devastating event of Acute Exacerbation of IPF (AE-IPF) needs to be clarified. This study examined the association between long-term personal air pollution exposure and AE- IPF risk taking into consideration inflammatory mediators and telomere length (TL). Methods: All consecutive IPF-patients referred to our Hospital from October 2013-June 2019 were included. AE-IPF events were recorded and inflammatory mediators and TL measured. Long-term personal air pollution exposures were assigned to each patient retrospectively, for O3, NO2, PM2.5 [and PM10, based on geo-coded residential addresses. Logistic regression models assessed the association of air pollutants’ levels with AE-IPF and inflammatory mediators adjusting for potential confounders. Results: 118 IPF patients (mean age 72 ± 8.3 years) were analyzed. We detected positive significant associations between AE-IPF and a 10 μg/m3 increase in previous-year mean level of NO2 (OR = 1.52, 95%CI:1.15–2.0, p = 0.003), PM2.5 (OR = 2.21, 95%CI:1.16–4.20, p = 0.016) and PM10 (OR = 2.18, 95%CI:1.15–4.15, p = 0.017) independent of age, gender, smoking, lung function and antifibrotic treatment. Introduction of TL in all models of a subgroup of 36 patients did not change the direction of the observed associations. Finally, O3 was positively associated with %change of IL-4 (p = 0.014) whilst PM2.5, PM10 and NO2 were inversely associated with %changes of IL-4 (p = 0.003, p = 0.003, p = 0.032) and osteopontin (p = 0.013, p = 0.013, p = 0.085) respectively. Conclusions: Long-term personal exposure to increased concentrations of air pollutants is an independent risk factor of AE-IPF. Inflammatory mediators implicated in lung repair mechanisms are involved.