Long-term exposure to ambient air pollution is associated with an increased incidence and mortality of acute respiratory distress syndrome in a large French region.

Introduction: Air pollution exposure is suspected to alter both the incidence and mortality in acute respiratory distress syndrome (ARDS). The impact of chronic air pollutant exposure on the incidence and mortality of ARDS from various aetiologies in Europe remains unknown. The main objective of this study was to evaluate the incidence of ARDS in a large European region, 90-day mortality being the main secondary outcome.

Methods: The study was performed in the Provence-Alpes-Cote-d'Azur (PACA) region. Nitrogen dioxide (NO2), particulate matter (PM and PM) and ozone (O3) were measured. The Programme de Médicalisation des Systèmes d'Information (PMSI), which captures all patient hospital stays in France, was used to identify adults coded as ARDS in an intensive care unit.

Results: From 2016 to 2018, 4733 adults with ARDS treated in intensive care units were analysed. The incidence rate ratios for 1-year average exposure to PM and PM were 1.207 ([95% confidence interval (95% CI), 1.145-1.390]; P < 0.01) and 1.168 (95% CI, 1.083-1.259; P < 0.001), respectively. The same trend was observed for both 2- and 3-year exposures, while only chronic 1- and 2-year exposure NO exposures were related to a higher incidence of ARDS. Increased PM exposure was associated with a higher 90-day mortality for both 1- and 3-year exposures (OR 1.096 (95% CI, 1.001-1.201) and 1.078 (95% CI, 1.009-1.152), respectively). O was not associated with either of incidence nor mortality.

Conclusions: While chronic exposure to NO2, PM2.5, and PM10 was associated with an increased ARDS incidence and a higher mortality rate (for PM2.5) in those patients presenting with ARDS, further research on this topic is required.