There has been much ambiguity about the relationship between smoking and covid since the beginning of the pandemic. Doctors have warned that smokers should be more vulnerable to respiratory diseases in general, but at the same time there have been indications that cigarette smoke may to some extent protect them from the virus that enters the body.
Later, however, it turned out that the work that stated this was wrong – its authors did not state when they published that they had financial links with the tobacco industry. However, other research looking at whether smoking is more likely to lead to a more severe course of covid has yielded conflicting results.
One problem is that many of these studies were simply “observational” – that is, doctors monitored only a few groups of people and tried to calculate what their properties would show negatively or positively during covid. . However, it has proved virtually impossible to determine whether smoking is the cause of the increased risk or whether there is something else – for example, the fact that smokers are more likely to come from lower socio-economic backgrounds.
The new study tried to solve this by analyzing a massive amount of data, which is also well marked and selected. The research was led by Ashley Clift of Oxford University. His team relied on GP records, covid-19 test results, hospital data and death certificates to find a link between smoking and covid severity between January and August 2020 at 421,469 a participant in the UK Biobank – all of them genetic analysis was also performed before.
What the data revealed
Compared to those who have never smoked, smokers are currently 80 percent more likely to be hospitalized and also more likely to die in the event of a covid infection.
Clift and his team used a technique called Randel Mendelian – it is named after the famous geneticist Brno. It uses genetic variants as substitutes for a certain risk factor – in this case genetic variants, which contribute to whether someone smokes more often or smokes a lot. This in turn serves as a path to further evidence that this is indeed a causal link, not just a coincidence.
“This study contributes to our confidence that smoking tobacco products does not protect against covid; Mendel’s randomization analyzes are less prone to confusion than older observational studies, ”the researchers said in the journal Thorax.
At the same time, a Mendelian randomization analysis confirmed the association between smoking and poorer outcomes with covid-19. She found that a genetic predisposition to smoking is associated with a forty-five percent higher risk of infection and a sixty percent higher risk of hospitalization.
The team found that a genetic predisposition to heavy smoking was associated with more than a double increase in the risk of infection, a five-fold increase in the risk of hospitalization, and a ten-fold increase in the risk. dying from the virus.
Clift adds: “Just as smoking seems to affect the risk of heart disease, various cancers and many other diseases, so does the virus that causes covid. So now is the best time to quit smoking and quit. cigarettes. “