@article {Gallus220191, author = {Silvano Gallus and Marco Scala and Irene Possenti and Carlotta Micaela Jarach and Luke Clancy and Esteve Fernandez and Giuseppe Gorini and Giulia Carreras and Maria Chiara Malevolti and Alison Commar and Ranti Fayokun and Hebe N. Gouda and Vinayak M. Prasad and Alessandra Lugo}, title = {The role of smoking in COVID-19 progression: a comprehensive meta-analysis}, volume = {32}, number = {167}, elocation-id = {220191}, year = {2023}, doi = {10.1183/16000617.0191-2022}, publisher = {European Respiratory Society}, abstract = {The association between current smoking and coronavirus disease 2019 (COVID-19) progression remains uncertain. We aim to provide up-to-date evidence of the role of cigarette smoking in COVID-19 hospitalisation, severity and mortality. On 23 February 2022 we conducted an umbrella review and a traditional systematic review via PubMed/Medline and Web of Science. We used random-effects meta-analyses to derive pooled odds ratios of COVID-19 outcomes for smokers in cohorts of severe acute respiratory syndrome coronavirus 2 infected individuals or COVID-19 patients. We followed the Meta-analysis of Observational Studies in Epidemiology reporting guidelines. PROSPERO: CRD42020207003. 320 publications were included. The pooled odds ratio for current versus never or nonsmokers was 1.08 (95\% CI 0.98{\textendash}1.19; 37 studies) for hospitalisation, 1.34 (95\% CI 1.22{\textendash}1.48; 124 studies) for severity and 1.32 (95\% CI 1.20{\textendash}1.45; 119 studies) for mortality. Estimates for former versus never-smokers were 1.16 (95\% CI 1.03{\textendash}1.31; 22 studies), 1.41 (95\% CI: 1.25{\textendash}1.59; 44 studies) and 1.46 (95\% CI 1.31{\textendash}1.62; 44 studies), respectively. Estimates for ever- versus never-smokers were 1.16 (95\% CI 1.05{\textendash}1.27; 33 studies), 1.44 (95\% CI 1.31{\textendash}1.58; 110 studies) and 1.39 (95\% CI 1.29{\textendash}1.50; 109 studies), respectively. We found a 30{\textendash}50\% excess risk of COVID-19 progression for current and former smokers compared with never-smokers. Preventing serious COVID-19 outcomes, including death, seems the newest compelling argument against smoking.We found an excess risk of progression of COVID-19 of 30{\textendash}50\% for current and ex-smokers compared to never-smokers. Our results suggest that a non-negligible proportion of the 6.2 million deaths worldwide due to COVID-19 are attributable to tobacco smoking. https://bit.ly/3TXLUy8}, issn = {0905-9180}, URL = {https://err.ersjournals.com/content/32/167/220191}, eprint = {https://err.ersjournals.com/content/32/167/220191.full.pdf}, journal = {European Respiratory Review} }