Air Pollution and post-acute sequelae of Covid-19: a multicentric study based on the EuCARE Project

<bold>Introduction:</bold> While exposure to air pollution has been found to be associated with higher COVID-19 severity, its relationship with post-acute sequelae of covid (PASC) is unknown <bold>Objectives:</bold> We aimed to assess whether exposure to air pollution was related to persistent symptoms after resolution of the acute phase of COVID-19 <bold>Methods:</bold> Non-vaccinated participants of EuCARE PASC cohort enrolled in 4 of the participanting centres in Europe and Brazil infected with SARS CoV2 from the onset of the pandemic to October 2021 and evaluated >1 month thereafter were included. Data on demographics, comorbidities and clinical symptoms of PASC were collected. Exposure to air pollutants over 2017-2019 was estimated based on participants’ addresses. We studied the effect of air pollution on PASC incidence and phenotypes adjusted for calendar time, socio-economic status and presumed colliders by means of standard logistic regressions. <bold>Results:</bold> We included 903 patients (56% men) with a median prevalence of 2 comorbidities and less than 10% outpatients. A total of 692 patients (77%) met WHO criteria for PASC, 231 (26%) presenting with a brain fog symptoms and 388 (43%) with a cluster of respiratory symptoms. Exposure to particulate matter (PM2.5) and nitrogen dioxide (NO2) was associated with a lower risk of PASC (aOR 0.72 (0.63-0.83] and 0.9[0.84-0.97]) and respiratory symptoms (aOR 0.8 [0.71-0.91] and 0.77 [0.72-0.82]) but higher risk of brainfog (aOR 1.67 [1.46-1.92] and 1.39 [1.29-1.50]). Discussion: Exposure to air pollution appeared to bring about different effects on PASC presentation. Further research is needed to support these findings and elicit possible biological mediators.