Tobacco and COVID-19 mortality

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Tobacco and COVID-19 mortality
  • 31 May, 2020

Dr Hitesh R Singhavi, Consultant Head and Neck Surgeon, Fortis, Mulund, Mumbai
Dr Pankaj Chaturvedi, Professor, Tata Memorial Center, Mumbai.

Introduction :

WHO (World Health Organisation) declared COVID-19 disease as pandemic on 11th March 2020.

  • The first COVID-19 infection can be traced to Wuhan, Hubei province, China in December 2019 and since then it has rapidly spread to 200 countries up till now. Till May 2020, there have been approximately 5,500,000 COVID 19 infected patients and around 350,000 have died due to the infection.
  • 1700000 patients have recovered, however beating the disease could also be just the start of the long-fought battle. Few preliminary studies have shown that survivors suffer from poorer functioning of their lungs, heart and liver.
  • Similarly, in India, as of the month of May there are 150000 Infected patients even after strict governmental measures including Nations' lockdown and implementation of social distancing. In the wake of diluting governmental measures with the prediction of the peak at the end of June or first week of July, it’s crucial to identify high-risk category group of infected patients. Tobacco users properly fit in this category. Consistent with GATS 2 survey, 28.6% of the Indian population use tobacco in some form (combustible and smokeless tobacco (SLT). This proportion is as high as 42% in males.
  • Given such an outsized proportion of population consuming tobacco, there are raised concerns about these individuals having a greater risk of morbidity and mortality from infection.

 

Tobacco and its direct effects on COVID-19 outcome :

Tobacco smoke causes increased inflammation, overproduction of mucous and impaired mucociliary clearance. Another common route of action for tobacco and SARS-CoV-2 virus is angiotensin-converting enzyme 2, receptor site for nCoV virus. Nicotine present in the tobacco is liable for disturbing the angiotensin-converting enzyme (ACE) and Mas receptor axis mechanism, contributing to the event of cardiovascular pulmonary disease.

  • Thus, tobacco might aggravate the pulmonary damage caused by SARS-Cov-2.

 

Tobacco and comorbidity :

Tobacco not only has direct effects on the progression of COVID-19 infection but it also indirectly influences its outcome. Use of tobacco leads to impairment of endothelial function, causes an imbalance between antithrombotic and prothrombotic factors resulting in accelerated atherosclerotic changes and increases cardiovascular events.

  • Cumulatively with the presence of comorbidities like cardiovascular disease, diabetes, respiratory disease & hypertension, risk of death increases by 280%.
  • According to a large study analysing the correlation of outcomes of COVID -19 infection with comorbidity status, it was found that presence of comorbidity results in 1.8 times poorer outcome. Also, a greater number of comorbidities (more than 2) is associated with poor survival.
  • It is a well-documented incontrovertible fact that smoking and use of SLT is one of the major risk factors of comorbidities like hypertension, diabetes, respiratory disease (COPD) and malignancy.

 

Tobacco and COPD and COVID-19 :

COPD (Chronic obstructive pulmonary disease) is a global public health crisis with more than 3.17 million deaths in 2015. Tobacco smoking is one of the major causative factors of COPD. As defined by GOLD guidelines it has been reported that 50% of all the lifelong smokers develop COPD in their lifetime.

  • Thus, considering a higher incidence of COPD due to such a large number of tobacco users, they all stand at greater risk of mortality due to COVID-19 infections. In a systematic review and meta-analysis which included 2473 COVID positive patients, the author showed 2.3 times higher association of progression of COVID-19 with history of smoking as compared to non-smokers. They also showed that mortality due to COVID-19 with underlying COPD and current smoking habit increases to 38.5% as compared to 2-3% in healthy individuals.
  • Outcomes of the Novel Flu drastically dip in the presence of smoking.

 

Gender predisposition of COVID-19 and smoking status :

According to a meta-analysis conducted on 3069 patients analysing clinical characteristics in COVID-19 showed that 56.7% of all the patients were male.

  • Similarly, according to the New York Health report, 61.8% of deaths were reported in males. As per the WHO website, the fatality rate of the infection in men (4.7%) was higher than women (2.7%). Therefore, both infection rate and death rate were typically skewed towards the male gender. According to Hua Cai, gender predilection may be attributed to the greater expression of ACE-2 in men as compared to women.
  • One of the Chinese studies stated expression of ACE-2 receptor was more in Asian men which might have been the reason for the higher prevalence in them. Similarly, another Chinese study found a bigger incidence of critically ill Covid-19 patients in males.
  • This can be attributed to the higher prevalence of smoking in Chinese men. However, evidence for the direct correlation between smoking and Covid-19 remains awaited.

 

SLT and COVID-19 :

India is the biggest market of chewing tobacco. There’s currently no evidence to state the direct role of smokeless tobacco on the mortality of COVID-19 infection. However, the use of smokeless tobacco certainly increases salivation which can raise chances of spitting in public place thus increasing the probabilities of COVID-19 infection spread.

 

Unproven claim :

WHO (World Health Organisation) is constantly examining new research, including investigation which study the direct correlation between nicotine use, and COVID-19 prevention. It is hypothesized that by preventing the virus from binding to its receptor (nicotinic acetylcholine receptor or nAChR) nicotine would help prevent COVID-19 infection.

  • The trial is not yet complete thus there is currently no evidence to support the role of Nicotine in the prevention of COVID-19 infection. Thus, WHO in its statement issued on 11th May 2020 has urged researchers, scientists and the media to be vigilant about reverberating proposal that tobacco or nicotine could reduce the danger of COVID-19 infection.

 

Conclusion :

There’s enough evidence to suggest poorer survival outcomes of COVID-19 infections in the presence of tobacco smoking. Healthcare worker and the public, in general, should be educated to identify these high-risk individuals. With prediction studies hinting towards coexistence of SARS-Cov-2 virus till 2022, cessation of Tobacco smoking may play a significant role in reducing the spread and flattening the death curve of this pandemic.

 

References :