Impact of Indoor Air Pollution on Health Outcomes in Patients with Idiopathic Pulmonary Fibrosis

초록

Introduction: While the effects of outdoor air pollution are well-known, those of indoor air pollution, particularly exposure to particulate matter with aerodynamic diameter ≤2.5 μm (PM 2.5), on patients with idiopathic pulmonary fibrosis (IPF) are unclear. Our study aimed to investigate the effects of indoor PM2.5 on the health outcomes in IPF patients. Methods: This multicenter prospective cohort study included 142 IPF patients from 12 institutions in South Korea. Quarterly assessments, including pulmonary function tests, quality of life questionnaires, and Krebs von den Lungen-6 (KL-6) level measurements, were performed over one year. Disease progression (DP) was defined as a relative decline of 10% in forced vital capacity (FVC) or 15% in diffusing capacity for carbon monoxide. Indoor PM2.5 levels were measured for five days at baseline and at 3, 6, and 9 months after enrollment using a MicroPEM device (RTI International, USA). Results: Of 142 participants, 127 with PM2.5 measurements were included (mean age: 69.4 years, male: 83.5%). The median value of annual average PM2.5 levels were 11.4 µg/m³ (interquartile range: 8.6-14.9 µg/m³). Baseline PM2.5 levels were correlated with KL-6 levels (r=0.216, p=0.016) and FVC (r = −0.159, p = 0.076). Cox regression analysis adjusting for clinical and socioeconomic factors showed that a 10 µg/m³ increase in annual average PM2.5 levels was associated with a 30.4% increase in DP (hazard ratio: 1.304, 95% confidence interval: 1.010—1.051). Conclusions: Indoor exposure to PM2.5 was correlated with higher KL-6 levels and increased the risk of DP in patients with IPF.