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This is a surprising result. Smokers are far LESS likely to be hospitalized with COVID-19 that non-smokers and it looks robust across countries.
Why might this be? https://twitter.com/KlausKblog/status/1249048902495592450
Why might this be? https://twitter.com/KlausKblog/status/1249048902495592450
The US data from CDC is... well shocking. Almost literally unbelievable.
Only 1.3% of U.S. COVID-19 cases are current smokers. Only 2.3% are former smokers.
Possible explanation? Nicotine lowers ACE2 expression. (SARS-CoV-2 uses ACE2 for entry into target cells.)
https://ncbi.nlm.nih.gov/pmc/articles/PMC6295500/
https://ncbi.nlm.nih.gov/pmc/articles/PMC6295500/
One major New York hospital system that has released its data has a lot more smoking than the CDC data, but notably they have the odds ratio for tobacco use at less than 1. https://twitter.com/leorahorwitzmd/status/1249319859378405377
Contra the theory above, a study from China finds higher ACE2 expression in smokers. https://www.medrxiv.org/content/10.1101/2020.03.18.20038455v1
Question for the biochemists... *if* (big if!) there is a nicotine protective effect, is there an analog or derivative that could produce the same effect without the harms of nicotine?
Another more complex theory of the potential mechanism, this one more consistent with the recent study in China. https://twitter.com/TrevorSutcliffe/status/1249767401899454470
Several respondents have pointed me to this paper coauthored by Dr. Raymond Niaura, Interim Chair of the Department of Epidemiology at NYU.
https://www.qeios.com/read/article/561
https://www.qeios.com/read/article/561
Should note this disclaimer on the U.S. data from CDC. Let's see what the next update looks like.
There's a preprint on that French hospital data now. https://twitter.com/KlausKblog/status/1252418954435256326
Another French pre-print outlining a potential mechanism for a nicotine protective effect. https://www.qeios.com/read/article/581
The theory of a nicotine protective effect is going to be tested in French hospitals using nicotine patches on health workers and patients. https://www.theguardian.com/world/2020/apr/22/french-study-suggests-smokers-at-lower-risk-of-getting-coronavirus?CMP=share_btn_tw
More U.S. data.
Covid-19 Testing, Hospital Admission, and Intensive Care Among 2,026,227 United States Veterans Aged 54-75 Years
"Smoking, COPD, and alcohol use disorder were associated with a LOWER probability of a positive test."
https://www.medrxiv.org/content/10.1101/2020.04.09.20059964v1.full.pdf
Covid-19 Testing, Hospital Admission, and Intensive Care Among 2,026,227 United States Veterans Aged 54-75 Years
"Smoking, COPD, and alcohol use disorder were associated with a LOWER probability of a positive test."
https://www.medrxiv.org/content/10.1101/2020.04.09.20059964v1.full.pdf
The French high school study:
Smokers had a lower IAR compared to non-smokers (7.2% versus 28.0%, P <0.001). https://www.medrxiv.org/content/10.1101/2020.04.18.20071134v1
Smokers had a lower IAR compared to non-smokers (7.2% versus 28.0%, P <0.001). https://www.medrxiv.org/content/10.1101/2020.04.18.20071134v1
