Living near a major road may accelerate lung function decline in IPF patients

02 Oct 2023 bởiStephen Padilla
Living near a major road may accelerate lung function decline in IPF patients

People with idiopathic pulmonary fibrosis (IPF) who live near a major road tend to have a faster decrease in lung function, according to a study in Australia. Likewise, increased exposure to fine particulate matter (<2.5 μm, PM2.5) is associated with a higher rate of annual decline in diffusing capacity of the lungs for carbon monoxide (DLco).

“This study adds to the evidence for the negative effects of air pollution on lung function in people with IPF living at low-level concentrations of exposure,” the investigators said. “Improved strategies such as the environmental legislation and community-level education can therefore be instrumental in reducing the risk to these susceptible patients.”

The Australian IPF Registry was used to recruit participants (n=570) for this study. The investigators assessed the impact of air pollution on changes in lung function using linear mixed models and explore its association with rapid progression through Cox regression.

The median (25th‒75th percentiles) annual PM2.5 was 6.8 μg/m3, while the median nitrogen dioxide (NO2) was 6.7 ppb. [Respirology 2023;28:916-924]

IPF patients who were living within 100 m from a major road showed a 1.3-percent predicted/year (95 percent confidence interval [CI], ‒2.4‒0.3) faster annual decline in DLco compared with those living more than 100 m from a major road. Each interquartile range of 2.2- μg/m3 increase in PM2.5 also contributed to a 0.9-percent predicted/year (95 percent CI, ‒1.6 to ‒0.3) faster annual decline in DLco.

On the other hand, no association was seen with NO2. Likewise, air pollution showed no significant association with rapid progression of IPF.

“Proximity of residential addresses has been shown to be associated with lung function decline in healthy adults, and predisposition to the development of COPD and asthma,” the investigators said. [Am J Respir Crit Care Med 2015;191:656-664; Respir Res 2005;6:152; Environ Int 2018;113:170-176]

“For people with IPF, we found that living <100 m from a major road was associated with a mean of 1.3-percent predicted faster annual decline in DLco compared to living more than 100 m,” they added.

Air pollution

Notably, the finding on the absence of an increased risk of rapid IPF progression was consistent with that of a previous study, which showed that living near a major road did not correlate with a higher risk of mortality in IPF. [Chest 2018;153:1221-1228]

“This study adds to the evidence for the detrimental effects of air pollution on lung function in patients with IPF even at low-level concentrations, highlighting that there is no safe level of air pollution and suggesting that policies and strategies to minimize air pollution should be implemented as soon as possible,” the investigators said.

“Our cohort included a well-characterized population from a prospective national registry, with detailed identification of exposures. Lung function data were collected as part of routine care, which is not subject to observer bias,” they added.

This study represented a relatively large cohort available for analysing the impact of air pollution on IPF patients compared to previous studies, but its sample size remains small for such analysis. [Thorax 2018;73:145-150; Chest 2018;153:1221-1228; Chest 2018;154:119-125; Eur Respir J 2014;43:1124-1131; Respir Res 2021;22:80]

“Lack of associations between air pollution and rapid progression of IPF seen in our cohort could be due to the study being underpowered,” the investigators said. “Future studies should include larger sample size to validate our results.”