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Published on: July 12, 2024
Association of Particulate Matter Exposure With Lung Function and Mortality Among Patients With Fibrotic Interstitial
Gillian C Goobie1,2,3, Christopher Carlsten4,5, Kerri A Johannson6
1Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania.
Importance:
Particulate matter 2.5 μm or less in diameter (PM2.5) is associated with adverse outcomes for patients with idiopathic pulmonary fibrosis, but its association with other fibrotic interstitial lung diseases (fILDs) and the association of PM2.5 composition with adverse outcomes remain unclear.
Objective:
To investigate the association of PM2.5 exposure with mortality and lung function among patients with fILD.
Design, Setting, And Participants:
In this multicenter, international, prospective cohort study, patients were enrolled in the Simmons Center for Interstitial Lung Disease Registry at the University of Pittsburgh in Pittsburgh, Pennsylvania; 42 sites of the Pulmonary Fibrosis Foundation Registry; and 8 sites of the Canadian Registry for Pulmonary Fibrosis. A total of 6683 patients with fILD were included (Simmons, 1424; Pulmonary Fibrosis Foundation, 1870; and Canadian Registry for Pulmonary Fibrosis, 3389). Data were analyzed from June 1, 2021, to August 2, 2022.
Exposures:
Exposure to PM2.5 and its constituents was estimated with hybrid models, combining satellite-derived aerosol optical depth with chemical transport models and ground-based PM2.5 measurements.
Main Outcomes And Measures:
Multivariable linear regression was used to test associations of exposures 5 years before enrollment with baseline forced vital capacity and diffusion capacity for carbon monoxide. Multivariable Cox models were used to test associations of exposure in the 5 years before censoring with mortality, and linear mixed models were used to test associations of exposure with a decrease in lung function. Multiconstituent analyses were performed with quantile-based g-computation. Cohort effect estimates were meta-analyzed. Models were adjusted for age, sex, smoking history, race, a socioeconomic variable, and site (only for Pulmonary Fibrosis Foundation and Canadian Registry for Pulmonary Fibrosis cohorts).
Results:
Median follow-up across the 3 cohorts was 2.9 years (IQR, 1.5-4.5 years), with death for 28% of patients and lung transplant for 10% of patients. Of the 6683 patients in the cohort, 3653 were men (55%), 205 were Black (3.1%), and 5609 were White (84.0%). Median (IQR) age at enrollment across all cohorts was 66 (58-73) years. A PM2.5 exposure of 8 μg/m3 or more was associated with a hazard ratio for mortality of 4.40 (95% CI, 3.51-5.51) in the Simmons cohort, 1.71 (95% CI, 1.32-2.21) in the Pulmonary Fibrosis Foundation cohort, and 1.45 (95% CI, 1.18-1.79) in the Canadian Registry for Pulmonary Fibrosis cohort. Increasing exposure to sulfate, nitrate, and ammonium PM2.5 constituents was associated with increased mortality across all cohorts, and multiconstituent models demonstrated that these constituents tended to be associated with the most adverse outcomes with regard to mortality and baseline lung function. Meta-analyses revealed consistent associations of exposure to sulfate and ammonium with mortality and with the rate of decrease in forced vital capacity and diffusion capacity of carbon monoxide and an association of increasing levels of PM2.5 multiconstituent mixture with all outcomes.
Conclusions And Relevance:
This cohort study found that exposure to PM2.5 was associated with baseline severity, disease progression, and mortality among patients with fILD and that sulfate, ammonium, and nitrate constituents were associated with the most harm, highlighting the need for reductions in human-derived sources of pollution.
Insights
Exposure to fine particulate matter (PM2.5) is linked to worse outcomes in fibrotic interstitial lung diseases (fILD). Sulfate, ammonium, and nitrate components of PM2.5 are particularly harmful, emphasizing the need to reduce pollution.
Area of Science:
- Environmental Health
- Pulmonary Medicine
- Epidemiology
Background:
- Particulate matter 2.5 (PM2.5) is linked to adverse outcomes in idiopathic pulmonary fibrosis.
- Associations between PM2.5 composition and outcomes in other fibrotic interstitial lung diseases (fILDs) are unclear.
Purpose of the Study:
- To investigate the association between PM2.5 exposure and mortality and lung function in patients with fILD.
- To examine the impact of specific PM2.5 constituents on fILD patient outcomes.
Main Methods:
- A prospective, multicenter cohort study involving 6683 patients with fILD across three registries.
- PM2.5 exposure and constituents estimated using hybrid models; statistical analyses included multivariable regression and Cox models.
- Meta-analyses were performed to consolidate findings across cohorts.
Main Results:
- Higher PM2.5 exposure was associated with increased mortality across all cohorts.
- Exposure to sulfate, nitrate, and ammonium PM2.5 constituents correlated with increased mortality.
- Multiconstituent analyses indicated these components were linked to the most adverse outcomes for mortality and lung function.
Conclusions:
- PM2.5 exposure is associated with baseline severity, disease progression, and mortality in fILD patients.
- Sulfate, ammonium, and nitrate are key harmful constituents of PM2.5.
- Reducing human-derived pollution sources is crucial for mitigating adverse health effects in fILD.
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