A study conducted in a large French university hospital, between March and April 2020, looking for a possible correlation between daily smoking and the susceptibility of contracting the SARS-CoV-2 infection, had indicated that the daily smokers‘ rate amongst COVID-19 patients was at 5.3%, whilst within the general French population, the rate of daily smokers rate was of 25.4%.
These findings had led the researchers concluding that daily smokers have a significantly lower probability of developing symptomatic or a severe SARS-CoV-2 infection, when compared to the general population.
Less smokers than non-smokers among COVID-19 patients
Similarly, another review of the Chinese data published in the European Journal of Internal Medicine concluded that „active smoking does not apparently seem to be significantly associated with enhanced risk of progressing towards severe disease in COVID-19.“
The current study sought to expand on a previous analysis by calculating the prevalence odds ratio (POR) of smoking among hospitalized COVID-19 patients, while the association between smoking and disease severity and mortality was examined by random-effects meta-analyses.
Nicotine as a protective factor
A total of 7162 patients were included in the study, with 482 being smokers and in line with the findings by the original study, no statistically significant association was found between smoking and COVID-related mortality rates.
“An unusually low prevalence of smoking, approximately 1/4th the expected prevalence, was observed among hospitalized COVID-19 patients. Any association between smoking and COVID-19 severity cannot be generalized but should refer to the seemingly low proportion of smokers who develop severe COVID-19 that requires hospitalization,” concluded the study.
The researchers made reference to other research suggesting that nicotine may act as a protective factor. “Smokers should be advised to quit due to long-term health risks, but pharmaceutical nicotine or other nicotinic cholinergic agonists should be explored as potential therapeutic options, based on a recently presented hypothesis.”