Abstract
BACKGROUND: A small number of studies suggested that air pollution was associated with idiopathic pulmonary fibrosis (IPF) exacerbation, incidence and mortality. However, no studies to date were conducted in regions where air pollution is substantial. We aimed to investigate whether there are associations between acute increases in air pollution and hospitalization of patients with a confirmed primary diagnosis of IPF in Beijing. METHODS: Daily count of IPF hospitalizations (International Classification of Disease-10th Revision, J84.1) was obtained from an administrative database for 2013-2017 while daily city-wide average concentrations of PM(10), PM(2.5), NO(2), Ozone, SO(2) were obtained from 35 municipal monitoring stations for the same period. The association between daily IPF hospitalization and average concentration of each pollutant was analyzed with a generalized additive model estimating Poisson distribution. RESULTS: Daily 24-h mean PM(2.5) concentration during 2013-2017 was 76.7 μg/m(3). The relative risk (RR) of IPF hospitalization per interquartile range (IQR) higher (72 μg/m(3)) in PM(2.5) was 1.049 (95% CI 1.024-1.074) and 1.031 (95% CI 1.007-1.056) for lag0 and moving averages 0-1 days respectively. No significant associations were observed for other lags. Statistically significant positive associations were also observed at lag0 with SO(2), Ozone and NO(2) (in men only). Positive associations were seen at moving averages 0-30 days for PM(10) (RR per 86 μg/m(3): 1.021, 95% CI 0.994-1.049), NO(2) (RR per 30 μg/m(3): 1.029, 95% CI 0.999-1.060), and SO(2) (RR per 15 μg/m(3): 1.060 (95% CI 1.025-1.097), but not with PM(2.5) or Ozone. CONCLUSIONS: Despite improvement in air quality since the implementation of clean air policy in 2013, acute exposure to higher levels of air pollution is significantly associated with IPF hospitalization in Beijing. Air quality policy should be continuously enforced to protect vulnerable IPF populations as well as the general public.