Air pollution exposure and its effects on idiopathic pulmonary fibrosis: clinical worsening, lung function decline, and radiological deterioration

Abstract

Introduction: Major urban pollutants have a considerable influence on the natural history of lung disease. However, this effect is not well known in idiopathic pulmonary fibrosis (IPF).

Aim: This study aimed to investigate the effects of air pollution on clinical worsening, lung function, and radiological deterioration in patients with IPF.

Methods: This exploratory retrospective cohort study included 69 patients with IPF, monitored from 2011 to 2020. Data on air pollution levels, including carbon monoxide (CO), nitrogen dioxide (NO₂), particulate matter ≤ 2.5 μM (PM_2.5), ozone (O₃), and nitrogen oxides (NO_x), were collected from the nearest air quality monitoring stations (<3.5 km from the patients' homes). Patient outcomes such as clinical worsening, lung function decline, and radiological deterioration were assessed over various exposure periods (1, 3, 6, 12, and 36 months). The statistical analyses were adjusted for various factors, including age, sex, smoking status, and treatment.

Results: There was an association between higher O₃ levels and an increased likelihood of clinical worsening over 6 and 36 months of exposure (odds ratio [OR] and 95% confidence interval [CI] = 1.16 [1.01-1.33] and OR and 95% CI = 1.80 [1.07-3.01], respectively). Increased CO levels were linked to lung function decline over 12-month exposure periods (OR and 95% CI 1.63 = [1.01-2.63]). Lastly, radiological deterioration was significantly associated with higher CO, NO₂, and NO_x levels over 6-month exposure periods (OR and 95% CI = 2.14 [1.33-3.44], OR and 95% CI = 1.76 [1.15-2.66] and OR and 95% CI = 1.16 [1.03-1.3], respectively).

Conclusion: This study suggests that air pollution, specifically O₃, CO, NO₂, and NO_x, could affect clinical worsening, lung function, and radiological outcomes in patients with IPF. These findings highlight the potential role of air pollution in the progression of IPF, emphasizing the need for further research and air quality control measures to mitigate its effects on respiratory health.

Keywords: air pollution; clinical worsening; idiopathic pulmonary fibrosis; lung function decline; radiological deterioration.