Tuesday, August 11, 2020

Compelling Evidence that Smoking Protects Against Covid-19 & Reduces the Likelihood of ICU Admission

Long-term cigarette smoking is associated with a number of serious diseases, but not COVID-19. In fact, numerous studies demonstrate that smokers are far less likely to be diagnosed with coronavirus than are non-smokers. In June, Konstantinos Farsalinos and colleagues reviewed 18 published reports, finding “an unexpectedly low prevalence of current smoking among hospitalized patients with COVID-19.” (here). 

It is, however, an understatement to say that the quality of COVID-19 information and data is poor. That partly explains why the protective effect of smoking has not generated significant mainstream interest. That is likely to change. 

Last week, researchers from the Universities of Oxford and Nottingham published a prospective cohort study of 19,500 coronavirus patients in the UK, 1,300 of whom ended up in intensive care units (ICUs) (here).  Their analysis, published in the British Medical Journal, found that smokers are far less likely to be diagnosed with COVID-19 and less likely to be admitted to an ICU.


The magnitude of the protection is not marginal. The above chart from the article shows that smokers are less than half as likely as non-smokers to be diagnosed with COVID-19.  Even more impressive, light smokers are 74% less likely to be in an ICU, and heavy smokers are 93% less likely. 

The BMJ study confirmed the elevated risks for other factors. For example, people over 60 years old were about twice as likely to be diagnosed and 6-7 times more likely to be in an ICU.  People with Type I diabetes were nearly three times more likely to be both diagnosed and end up in an ICU.  A body mass index of 30+ increased diagnoses by 24-60% and ICU admissions by 3- to 4-fold.  

Although smokers are clearly protected from COVID-19, it is not known how this is achieved. Farsalinos and colleagues believe that nicotine plays a role (here), however, fully understanding the mechanism will require a lot more research.

This is not an invitation to start smoking, but if the mechanism of protection involves nicotine, this finding might lead to a better understanding of how to avoid and treat this devastating pandemic.


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