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COVID-19, tobacco smoking, risk factors, quitting smoking
Introduction: COVID-19 pandemic burst onto the international scene as a new disease not affecting patients uniformly; hence it has risen many questions yet to be clarified. The aim of this study was to outline the main issues that led tobacco smoking being discussed as a potential risk factor associated with COVID-19. Methods: articles from MEDLINE and pre-prints published from January to April 2020 were identified. Results: data from China showed that men had more severe outcomes of COVID-19 than women. Since smoking prevalence is very high among Chinese men in comparison to women, it was hypothesized that smoking could be a risk factor for poor prognosis. This was also supported by the higher prevalence of comorbidities, many of which are tobacco-related diseases, in patients with severe COVID-19, who were also more likely to have a smoking history. A meta-analysis confirmed these results reporting an OR=2.25 (95% CI: 1.49-3.39) for developing severe Covid-19 among patients with a smoking history. Some authors, noticing that reported smoking prevalence among hospitalized patients was substantially below smoking prevalence in the corresponding populations, speculated a protective role of nicotine. However, it is likely that low prevalence among hospitalized patients are partially due to many smokers misclassified as nonsmokers. Tobacco smoking seems to cause a dose-dependent upregulation of the angiotensin-converting- enzyme-2 (ACE2), the virus cellular entry receptor, which could explain the higher risk of severe COVID-19 in smokers. Conclusions: There is need for further independent studies to clarify the role of smoking on COVID-19 incidence, progression and mortality.
2. Wu Z, McGoogan JM. Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China: Summary of a Report of 72 314 Cases From the Chinese Center for Disease Control and Prevention. JAMA 2020; 323; 13: 1239-1242 doi: 10.1001/jama.2020.2648
3. Guan WJ Ni ZY, Hu Y et al. Clinical Characteristics of Coronavirus Disease 2019 in China. N Engl J Med. 2020 Apr 30; 382(18):1708-1720. doi: 10.1056/NEJMoa2002032.
4. Huang C, Wang Y, Li X, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet. 2020; 395(10223): 497‐ 506.
5. Zhang JJ, Dong X, Cao YY et al. Clinical characteristics of 140 patients infected with SARS-CoV-2 in Wuhan, China. Allergy 2020; Feb 19. doi: 10.1111/all.14238.
6. Gattinoni L, Coppola S, Cressoni M et al. COVID-19 Does Not Lead to a “Typical” Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med. Published online March 30, 2020.
7. Gattinoni L, Chiumello D, Caironi P et al. COVID-19 pneumonia: different respiratory treatments for different phenotypes? Intensive Care Med (2020). https://doi.org/10.1007/s00134-020-06033-2.
8. Tang N, Li D, Wang X, Sun Z. Abnormal coagulation parameters are associated with poor prognosis in patients with novel coronavirus pneumonia. J Thromb Haemost. 2020 Apr; 18(4): 844-847. doi: 10.1111/jth.14768.
9. Choi KW, Chau TN, Tsang O et al. Outcomes and prognostic factors in 267 patients with severe acute respiratory syndrome in Hong Kong. Ann Inter Med 2003; 139: 715-23.
10. Alraddadi BM, Watson JT, Almarashi A, Abedi GR, Turkistani A, Sadran M. Risk factors for primary middle east respiratory syndrome coronavirus illness in Humans, Saudi Arabia, 2014. Emerg Infect Dis 2016; 22: 49-55.
11. Cai H. Sex difference and smoking predisposition in patients with COVID-19. Lancet Respir Med 2020; Apr;8(4):e20. doi: 10.1016/S2213-2600(20)30117-X
12. Markle JG, Fish EN. SeXX matters in immunity. Trends Immunol 2014; 35: 97-104 doi: 10.1016/j.it.2013.10.006
13. Taneja V. Sex hormones determine immune response. Front Immunol 2018; 9: 1931.
14. Pinheiro I, Dejager L, Libert C. X-chromosome-located microRNAs in immunity: might they explain male/female differences? The X chromosome genomic context may affect X-located miRNAs and downstream signaling, thereby contributing to the enhanced immune response of females. BioEssays 2011; 33: 791-802.
15. Zagà V, Gallus S, Gorini G, Cattaruzza MS. Perché il coronavirus è più mortale tra gli uomini che tra le donne. L’ipotesi tabagismo. Tabaccologia 2020; 1:21-29.
16. Epicentro. Il tabagismo ai tempi della COVID-19. Istituto Superiore di Sanità. https://www.epicentro.iss.it/coronavirus/sars-cov-2-dipendenze-fumo
17. Epicentro. Sorveglianza Integrata COVID-19 in Italia. Istituto Superiore di Sanità https://www.epicentro.iss.it/coronavirus/bollettino/Infografica_24aprile%20ITA.pdf
18. Matricardi PM, Dal Negro RW, Nisini R. The First, Comprehensive Immunological Model of COVID-19. Implications for Prevention, Diagnosis, and Public Health Measures. Preprints 2020, 2020040436
19. Emami A, Javanmardi F, Pirbonyeh N, and Akbari A. Prevalence of Underlying Diseases in Hospitalized Patients with COVID-19: a Systematic Review and Meta-Analysis. Arch Acad Emerg Mede 2020; 8(1): e35
20. Arcavi L, Benowitz NL. Cigarette Smoking and Infection. Arch Intern Med 2004; 164: 2206-16.
21. Qiu F, Liang CL, Liu H, et al. Impacts of cigarette smoking on immune responsiveness: up and down or upside down? Oncotarget 2017; 8: 268-84
22. Parascandola M, Xiao L. Tobacco and the lung cancer epidemic in China. Transl Lung Cancer Res 2019; 8(Suppl 1): S21–30. https://doi.org/10.21037/tlcr.2019.03.12.
23. Liu W, Tao ZW, Lei W, et al. Analysis of factors associated with disease outcomes in hospitalized patients with 2019 novel coronavirus disease. Chin Med J (Engl) 2020 Feb 28. doi: 10.1097/CM9.0000000000000775
24. Lippi G, Henry BM. Active smoking is not associated with severity of coronavirus disease 2019 (COVID-19). Eur J Intern Med 2020. S0953-6205(20)30110-2. doi:10.1016/j.ejim.2020.03.014
25. Vardavas C, Nikitara K. (2020). COVID-19 and smoking: A systematic review of the evidence. Tob Induc Dis, vol. 18 (March). doi:10.18332/tid/119324
26. Alqahtani JS, Oyelade T, Aldhahir AM, et al. Prevalence, Severity and Mortality associated with COPD and Smoking in patients with COVID-19: A Rapid Systematic Review and Meta-Analysis. medRxiv preprint doi: https://doi.org/10.1101/2020.03.25.20043745
27. Patanavanich R, Glantz SA. Smoking is Associated with COVID-19 Progression: A Meta-Analysis. 2020; medRxiv preprint. doi:10.1101/2020.04.13.20063669
28. Farsalinos K, Barbouni A, Niaura R. Smoking, vaping and hospitalization for COVID-19. 2020; Qeios. doi:10.32388/z69o8a.13.
29. Miyara M, Tubach F, Amoura Z. Low incidence of daily active tobacco smoking in patients with symptomatic COVID-19 infection. 2020; Qeios. doi:10.32388/wpp19w.
30. Changeux JP, Amoura Z, Rey F, Miyara M. A nicotinic hypothesis for COVID-19 with preventive and therapeutic implications. 2020; Qeios. doi: 10.32388/FXGQSB.2
31. Simons D, Shahab L, Brown J, Perski O. The association of smoking status with SARS-CoV-2 infection, hospitalisation and mortality from COVID-19: A living rapid evidence review. 2020; Qeios. doi:10.32388/UJR2AW.2
32. Epicentro. Sorveglianza Passi. Definizioni di fumatore. Istituto Superiore di Sanità https://www.epicentro.iss.it/passi/rapporto2010/R2010schedeIndicatoreFumo
33. Wang J, Luo Q, Chen, R, Chen T, Li J. Susceptibility analysis of COVID-19 in smokers based on ACE2. Preprints 2020, 2020030078. doi: 10.20944/preprints202003.0078.v1
34. Smith JC, Sheltzer JM. Cigarette smoke triggers the expansion of a subpopulation of respiratory epithelial cells that express the SARS-CoV-2 receptor ACE2. 2020; bioRxiv 2020.03.28.013672; doi: https://doi.org/10.1101/2020.03.28.01367
35. Leung JM, Yang CX, Tam A, et al. ACE-2 Expression in the Small Airway Epithelia of Smokers and COPD Patients: Implications for COVID-19. Eur Respir J 2020; in press (https://doi.org/10.1183/13993003.00688-2020)
36. Berlin I, Thomas D, Le Faou AL, Cornuz J. (2020). COVID-19 and Smoking. Nicotine & Tobacco Research 2020; 1–3. doi:10.1093/ntr/ntaa059.
37. Gorini G, Clancy L, Fernandez E, Gallus S. Smoking history is an important risk factor for severe COVID-19. Blog Tob Control. 5 April 2020. Available online at: https://blogs.bmj.com/tc/2020/04/05/smoking-history-is-an-important-risk-factor-for-severe-covid-19/