Smoking and vaping raises the risk of falling critically ill with Covid-19, experts have warned — despite a growing body of research showing the opposite.
German scientists reviewed available evidence on the damage smoking and vaping inflicts on vital organs in the body.
All three harden the arteries and raise the risk of developing lung and heart diseases — two risk factors for coronavirus — by up to seven-fold, they found.
As a result, the team believes smokers and e-cigarette users would be more likely to suffer complications from Covid-19.
They admitted smoking is more toxic on the body than vaping but warned research suggested vaping was ‘not a healthy alternative’.
The review — published in the European Heart Journal — did not actually analyse the hospital records of Covid-19 patients, however.
It means it does not offer any concrete evidence smoking makes the disease worse, and instead is only a warning based on reports — actual studies have suggested smoking could offer protection against the coronavirus.
One scientist said the methodology behind the review on how smoking and vaping damages the body was so sloppy ‘it cannot be described as a study’, while another described the findings as ‘questionable’.
The University of Mainz study compared the damage that smoking, vaping and using shisha pipes inflicts on the heart and lungs.
It found all three harden the arteries and increase the risk of lung and heart damage, but that tobacco cigarettes were in general more harmful than e-cigarettes.
Data has repeatedly shown Covid-19 patients with underlying health conditions are at much greater risk of suffering life-threatening complications or dying.
However, paradoxically, a growing body of research has indicated that cigarette users are actually less likely to be diagnosed with Covid-19 or be hospitalised, compared to non-smokers.
And hospital records have also suggested smokers who do catch the virus are no more likely to need intensive care, be hooked up to a ventilator or die.
Many scientists are coming round to the idea that nicotine may be able to block the virus from entering cells, preventing the infection in the first place.
Others say nicotine may control the immune system, stopping it from dangerously over-reacting to infection – a phenomenon found to kill many Covid-19 patients.
Writing in the latest study, the researchers, led by Professor Thomas Munzel, a cardiologist at Mainz, said: ‘As outlined by the WHO, tobacco cigarette and waterpipe smoking may contribute to increased burden of symptoms due to COVID-19 compared to non-smoking, including being admitted to intensive care, requiring mechanical ventilation, and suffering severe health consequences.
‘Since smoking per se is a well-established risk factor for respiratory infections and increases the probability of having pre-existing conditions such as heart disease, it could make COVID-19 patients more susceptible to severe symptoms, thus leading to increased mortality.
‘Accordingly, considering the potential acute pulmonary and cardiovascular toxicity of e-cigarettes, the use of these products may put patients at higher risk of severe illness from COVID-19.’
It is thought SARS-CoV-2 – the virus behind Covid-19 – enters the body by binding to receptors in the body called ACE-2, found along the respiratory tract.
Some research has suggested nicotine slashes the expression of ACE-2, which would imply smokers have less entry points for the virus to begin with.
Nicotine has also been shown to prevent lung damage in animals with acute respiratory syndrome, a life-threatening condition the coronavirus can lead to.
It’s been suggested that if smokers do see their disease progress while in hospital, it is due to withdrawal from nicotine, exacerbating lung damage.
Another theory is the virus first enters through the nicotinic acetylcholine receptor (nAChR), which is present around the nose and mouth.
This would explain why the virus causes a loss of taste and smell and in some cases, headaches, dizziness and intense fatigue.
Today’s study examined the effect of smoking, vaping and inhaling from shisha pipes on a host of other health conditions.
Covid-19 was only factored into the study at the last minute.
The findings are based on a review of the available evidence.
The researchers looked at the effects of the three habits on lung cancer and chronic obstructive pulmonary disease (COPD).
Compared to non-smokers, cigarette users faced a seven-fold greater risk of getting COPD.
The risk was double for waterpipes and e-cigarettes.
Smoking cigarettes and using waterpipes daily also increased the risk of lung cancer by 1,210 per cent and 122 per cent, respectively, when compared to those who did not smoke.
The researchers said, however, there was not enough evidence to assess the risk of e-cigarettes on lung cancer.
The team also looked at how much the three smoking techniques stiffened arteries, an important indicator for the risk of heart problems and stroke.
Compared to non-smokers, cigarettes increased arterial stiffness by around 10 per cent, waterpipes by 9 per cent, and e-cigarettes by 7 per cent.
The findings show, in general, traditional cigarettes are more harmful than vaping — but e-cigarettes come with their own risk.
Because all three types of smoking drives up the risk of developing underlying health conditions, the researchers guess that it will increase the chance of Covid-19 complications.
Commenting on the study, Professor John Britton, consultant in respiratory medicine at the University of Nottingham, said: ‘This paper provides an unsystematic overview on evidence relating to the likely relative risks of nicotine use, and of questionable reliability: for example, that e-cigarette use increases the risk of chronic obstructive pulmonary disease by 194 per cent but COPD is a disease with a lead time of decades, so to attribute a risk directly to e-cigarettes – which have been widely used for less than a decade and are almost exclusively used by former smokers – is inappropriate.’
Professor Jacob George, a cardiologist at the University of Dundee, added: ‘Firstly, this publication cannot be described a study. It is a clinical review of the available evidence.
‘It does not provide de novo evidence on its own.
Secondly, the authors correctly state that in terms of comparative risks of tobacco cigarettes are significantly greater than electronic cigarettes and the available evidence on the risk of e-cigarettes on lung cancer is not sufficient to draw any robust conclusions.
What we cannot say for certain, and the study does not provide further clarity on either, is how much of the effects seen in electronic cigarette smokers are due to prior tobacco cigarette use.
‘No study so far has accurately and absolutely quantified prior impact of tobacco cigarette smoking on vascular dysfunction in individual e-cigarette users as we know that most electronic cigarette smokers are former users of tobacco cigarettes and a number are dual users also.
‘Disentangling this from the distinctive impact of e-cigarettes on vascular function is still required to fully understand the risks versus the benefits of e-cigarettes, which on a comparative basis contains significantly fewer than the 7,000 harmful chemicals present in every tobacco cigarette that is smoked.’
WHY IS SMOKING THOUGHT TO PROTECT AGAINST THE CORONAVIRUS?
Swathes of studies have shown a low prevalence of smokers in hospitals with Covid-19.
If the findings are proven, scientists say it’s likely that it is not cigarettes – filled with thousands of harmful chemicals – that would offer a potential protection, but the nicotine that is beneficial.
A theory flouted by scientists is that nicotine reduces ACE-2 receptors, which are proteins in the body the virus binds to in order to infect cells.
The coronavirus enters cells inside the body via the structures, which coat the surface of some cells, including in the airways and lungs.
If nicotine does lowers ACE-2 expression, it makes it harder for viral particles to gain entry into cells and therefore cause an infection.
On the other hand, other studies show that nicotine enhances the action of the ACE-2 receptor, which in theory, puts smokers at a higher risk of contracting the coronavirus.
Other scientists say low levels of ACE-2 expression as a result of nicotine may prevent worse damage from viral infection, and there is no evidence that says higher quantities of ACE-2 receptors increases the risk of SARS-CoV-2 infection in the first place.
Dr Konstantinos Farsalinos, from the University of West Attica, Greece, who queried whether nicotine could be a cure for Covid-19 in a paper published on May 9, said: ‘Up-regulation of ACE2, though seemingly paradoxical, may in fact protect patients from severe disease and lung injury.’
A 2008 study in mice found that getting rid of ACE-2 made the animals more likely to suffer severe breathing difficulties when infected with the SARS virus, which is almost identical to Covid-19.
Other scientists have turned their head towards nicotine’s ability to prevent inflammation, where evidence is more robust.
Nicotine has been shown inhibit the production of pro-inflammatory cytokines, such as TNF, IL-1 and IL-6, which are involved in promoting an inflammatory response.
A ‘cytokine storm’ is a phenomenon in which an abundance of cytokines are released in response to infection.
Doctors have previously said that it’s often the body’s response to the virus, rather than the virus itself, that plays a major role in how sick a person gets.
A cytokine storm can lead to respiratory failure and the attack of healthy tissues, causing multi-organ failure. Therefore, the cytokine storm is being looked at as a target for COVID-19 treatment.
‘Nicotine has effects on the immune system that could be beneficial in reducing the intensity of the cytokine storm,’ Dr Farsalinos wrote in Internal and Emergency Medicine.
‘The potential benefits of nicotine…. could explain, at least in part, the increased severity or adverse outcome among smokers hospitalized for COVID-19 since these patients inevitably experience abrupt cessation of nicotine intake during hospitalization.
‘This may be feasible through repurposing already approved pharmaceutical nicotine products such as nicotine patches.’
Dr Nicola Gaibazzi, who recently published findings on MedRxiv of ‘very low’ numbers of smokers in Italian COVID-19 patients, speculates smoke exposure may bolster the immune system.
He said exposure to cigarette smoke reduces the body’s immune system over time, measured by lower inflammatory markers.
Therefore, when smokers are infected with a virus like SARS-CoV-2, their immune system is more ‘tolerant’ and does not overreact.
On the other hand, non-smokers may be more prone to having the sudden and deadly cytokine storm when they are infected with the virus.
(By Connor Boyd, Health Reporter For Mailonline and Eleanor Hayward Health Reporter For The Daily Mail)
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