Impact of Tobacco Smoking on the risk of COVID-19.A large scale retrospective cohort study

• Published in: Nicotine & Tobacco Research 2021-01
• Main Authors: Paleiron, Nicolas, Mayet, Aurélie, Marbac, Vanessa, Perisse, Anne, Barazzutti, Hélène, Brocq, François-Xavier, Janvier, Frédéric, Bertrand, Dautzenberg, Bylicki, Olivier
• Format: Article
• Language: English
• ISSN: 1469-994X
• DOI: 10.1093/ntr/ntab004

Preliminary reports indicated that smokers could be less susceptible to the coronavirus SARS-CoV-2, which causes Covid-19. However, once infected an increased risk of severe disease is reported. We investigated the association between smoking and COVID-19 during an outbreak of the disease on a naval vessel. We conducted a cross-sectional, observational study on the 1769 sailors of a same navy aircraft carrier at sea exposed at the same time to SARS-CoV2 to investigate the link between tobacco consumption and Covid-19. Among the 1688 crewmembers (87% men; median age= 28 (IQR 23-35)) included, 1279 (76%) developed Covid-19 (1038 (62%) RT-PCR-positive and 241 (14%) with only clinical signs). One hundred and seven patients were hospitalized. The univariable analysis odds ratio (OR) for Covid-19 infection was 0.59 (95% confidence interval (CI), 0.45-0.78; P50 years old had an increased risk of contracting Covid-19 (OR, 2.84 [95% CI, 1.30-7.5]; P=0.01). Multivariable analysis retained the lower risk of current smokers becoming infected (OR, 0.64 [0.49-0.84]; P50 years was significatively associated with Covid-19 (OR, 2.6 [1.17-6.9]; P=0.03). Current smoking status was associated with a lower risk of developing Covid-19 but cannot be considered as an efficient protection against infection. Mechanism of the lower susceptibility of smokers to SARS-CoV-2 requires further research. Recent epidemiologic data suggest a paradoxical link between smoking and Covid-19. Among the 1688 crewmembers (with an attack rate of 76% and exposed at the same time in the same place to SARS-CoV2), we found a significant lower risk for developing COVID-19 in current smokers (71%) versus former and non smokers (80%). This finding strongly supports the need for further research on nicotine physiological pathway and its impact on COVID-19 infection whilst emphasizing that tobacco smoking should not be considered as an efficient protection against COVID-19.