The impact of air pollution on COVID-19 severity among infected individuals in a population of italian MS patients

ABSTRACT

Introduction: Studies have found associations between air pollution and pneumonia and air pollution is an established risk factors for common COVID-19 complications including pneumonia. Additionally, air pollutants have been identified as possible risk factors for MS onset and relapses. To our knowledge, only one study explored the impact of air pollution on Covid-19 severity specifically among MS patients but has only focused on PM2.5 exposures. Aim(s) We aim to evaluate the association between long-term exposure to air pollution and COVID-19 severity, described as developing pneumonia in a population of COVID-19-positive MS patients. Method(s) Data on COVID-19 infection among MS patients were extracted from an Italian web-based platform (Musc-19). A casecontrol study was designed including patients with and without pneumonia at a case-control ratio of 12 and 615 patients were included. The included patients were asked to provide information on the geographical area where they had spent most time in the previous 5 years. When this information was missing, the address of the MS center was used as a proxy and evaluated in sensitivity analysis. Air quality was assessed as annual average particulate matter (PM2.5 and PM10) and Nitrogen Dioxide (NO2) ground-level concentrations derived from air quality model results as provided by the 'Copernicus Atmospheric Monitoring Service', and evaluated as categorical exposures (terciles). The association between pollutants and COVID-19 pneumonia was studied using logistic regression models, also adjusting for confounders (age, sex, BMI, comorbidities, EDSS, MS type, duration and treatments). Result(s) Detailed exposure was obtained for 491 patients, of whom 34% had pneumonia. Higher concentrations of air pollutants were associated with increased odds of developing COVID-19 pneumonia in both unadjusted and adjusted models (Adjusted models estimates PM2.5 2nd vs 1st tercile OR(95% CI)=2.09 (1.20;3.65), 3rd vs 1st tercile OR(95% CI)=2.26(1.29;3.96);PM10 2nd vs 1st tercile OR(95% CI)=1.83(1.05;3.20), 3rd vs 1st tercile OR(95% CI)=2.12(1.22;3.68);NO2 3rd vs 1st tercile OR(95% CI)=2.12(1.21;3.69)). Results remained consistent in the sensitivity analysis. Conclusion(s) Higher long-term concentrations of PM2.5, PM10 and NO2 were associated with COVID-19 pneumonia among MS patients. Urgent measures to reduce air pollution should be adopted especially to protect the most vulnerable population.