Smoking and COVID-19

It seems obvious to me that smoking will increase the severity of COVID-19, and to that extent I've heard respected Canadian medical experts on the radio explain why it seems obvious to them that smoking would be an aggravating factor as well.

Now it's true that Science doesn't progress just because things "seem obvious", and so I'm certainly happy for people to study the matter. It normally wouldn't be something I actually care that much about, but there's a minor internet disagreement over just why COVID-19 seems to be so much deadlier in men than it is in women, so I was enticed to click on a few links. Well here's where the fun begins.

First, I found the following website really clear in showing the split. Importantly, the number of cases is almost always a split between men and women, but the number of deaths is not. Secondly, to the smoking data. The original article cited this paper from the European Journal of Internal Medicine (EJIM) to say that smoking is not linked to Coronavirus. While a google search quickly revealed this paper from the journal of Tobacco Induced Diseases (TID), claiming that smoking IS linked. Neither is a high impact or widely cited journal, but both are peer reviewed and should be taken seriously.

The first, rather annoying thing to note is that both articles were working with almost exactly the same data set. EJIM had one novel study with 50 patients, while TID had a study with 191 patients. Both overwhelmingly relied on four other shared studies, one of which, with 1,085 patients spread out over Chana, overwhelmed the others in terms of data. Nevertheless, the conclusion of EJIM was "that active smoking does not apparently seem to be signicantly associated with enhanced risk of progressing towards severe disease in COVID-19." TID on the other hand concluded "although further research is warranted... smoking is most likely associated with the negative progression and adverse outcomes of COVID-19."

Arrghh, if paywalls weren't enough, how's the average person supposed to connect with scientific research. Anyway, a few conclusions.

1. It isn't entirely crazy to think smoking might not be terrible. Apparently it inhibits the ACE2 enzyme, the reported host receptor for SARS-COV2.

2. Both papers tempered their views a lot more than what is reflected in the conclusions. They both acknowledged that this was very early data.

3. All of these studies were from China (where smoking is predominantly by men). I'd really like to see something more international.

4. The pivot point here might be whether the trends of each study were "statistically significant". Most showed smokers having slightly worse health impacts.

5. If you want to write an article about how gender differences regard COVID-19 are mostly biology based, you now have a paper to cite. If you want to argue biology is meaningless and it comes down to lifestyle, you now have a paper to cite. If you want to actually know the answer, like me, you have to waste a morning sorting through the academic literature, which is annoying.