A recent correspondence published in the European Respiratory Journal described the potential impact of air pollution and socioeconomic status on the survival of patients with idiopathic pulmonary fibrosis (IPF). According to the authors, “Air pollution and poverty constitute a deadly mix in idiopathic pulmonary fibrosis.”

The authors commented on 2 previously published articles, one from Yoon et al and the other from their own group, that had differing results on the impacts of atmospheric NO2 and particulate matter on mortality in patients with IPF. The authors mentioned methodological differences between the 2 studies, including differences in how pollution exposure was measured and over what time period they were studied. The authors also mentioned that the studies took place in different countries (Korea vs France) with different pollutant levels.

The authors acknowledged the difficulties in accurately estimating exposure in patients with respiratory diseases, especially IPF. IPF generally develops over many years before patients are diagnosed. Most patients with IPF are older and may have lived in different locations prior to their diagnosis, especially if they moved for retirement or to be closer to their treatment center. Studies in patients with IPF also require longer time periods to achieve significant numbers of patients since IPF is rare. Air quality has also improved over time in most countries, which can make it harder to estimate previous exposure levels.

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The authors highlight the interesting observation that area-level covariates, including educational level and gross regional domestic product as a proxy for income, had a significant impact on the mortality rates of patients with IPF. Socioeconomic factors, including income and educational level, affect overall health and can also play a role in exposure to air pollution, with lower socioeconomic status and certain ethnic groups being more likely to live closer to pollution sources. These same factors can result in inadequate education about preventative health habits and affect access to medical care.

The authors stated, “The socioeconomic level may influence coexposures in [the] prenatal period and throughout life, and intervene on primary, secondary, and tertiary disease prevention. And by the time IPF appears, social conditions and environmental exposures have already been at work for many years.”

Given this information, they suggested, “an exposome approach, involving research in life and social sciences, would provide a better understanding of the influence of the environment on the genesis and severity of IPF.”


Sesé L, Annesi-Maesano I, Cavalin C, Nunes H. Air pollution and poverty: a deadly mix in idiopathic pulmonary fibrosis? Eur Respir J. Published online August 12, 2021. doi:10.1183/13993003.01714-2021

Yoon HY, Kim SY, Kim OJ, Song JW. Nitrogen dioxide increases the risk of mortality in idiopathic pulmonary fibrosis. Eur Respir J. 2021;57(5):2001877. doi:10.1183/13993003.01877-2020

Sesé L, Nunes H, Cottin V, et al. Role of atmospheric pollution on the natural history of idiopathic pulmonary fibrosis. Thorax. 2018;73(2):145-150. doi:10.1136/thoraxjnl-2017-209967