>there's a very real likelihood that Vit D deficiency may just be a proxy for an unhealthy lifestyle

Seriously! You think that it might be possible that vitamin D deficiency doesn't exist at all and that people used to get rickets because of an unhealthy lifestyle. You're kidding right ...?

In case, it's not clear, I repeat:

>By the way, I'm not advocating for long-term, high-dose consumption (say over 2000 IU) consumption of vitamin D.

What I am advocating for is:

>What we should be doing now is mass-testing the at-risk population to identify those people with blood levels below 30 ng/ml and then do what is necessary to bring them up into the 30 to 40 ng/ml range. ...

Actually, I agree that the evidence for supplementation with vitamin D for general health, and improving all-cause mortality isn't there. That's why I wrote:

>Ideally that could be done with sunlight, or food high in vitamin D - for example oily fish, liver, dried-shitake, ...

But there's a sharp difference between the general health, then general respiratory disease, then COVID-19. As Deva Boone writes:

>But maybe Covid is different. Covid is a respiratory infection, and in meta-analyses severe Vitamin D deficiency does appear to increase the risk of respiratory infections. We also have a plausible mechanism through which Vitamin D could influence Covid. ...

OK, now you quote Deva Boone:

>No, not really. There is suggestive evidence from a small pilot study. There is likely an effect,

Her position is disputed here [0] in the HN comments by kovach

devaboone
>Here is what the article states: "Therefore, a multivariate logistic regression analysis was performed to adjust the model by possible confounding variables such as hypertension and type 2 diabetes mellitus for the probability of the admission to the Intensive Care Unit in patients with Calcifediol treatment vs Without Calcifediol treatment (odds ratio: 0.03 (95%CI: 0.003-0.25) (Table 3). The dependent variable considered was the need to be treated or not in ICU (dichotomous variable).) CI:-0.30 - 0.03 p:0.08." The statement is worded in a confusing way, but that is a non-significant p value. Of course we should not put too much into "statistical significance" but it is interesting to note.

kovach
>The only reason that p value is a bit high in that second multivariate analysis is because of the uncertainty of how much all the different risk factors like hypertension, T2DM, age >= 60 etc. affect ICU admission numbers.
But even with those variables controlled, the 95% confidence interval is 0.003-0.25, which at worst is a 4-fold reduction in ICU risk.
>
>We should also note that the Calcifediol treatment group had 14 patients ≥ 60 years old, and the non-Calcifediol group had 5. So the study looks even better with that in mind...

Another thing about this study, is that it's actually megadosing. IIRC, something like 100,000 IU on day 1, 50,000 IU on day 3.

That's probably safe in the short-term in a hospital setting as devaboone states. But further more, it's probably necessary in the context of keeping COVID-19 patients out of the ICU. If they have COVID-19 because they're low in vitamin-D, then a 5000 IU capsule is probably not going to be enough.

That's why I'm advocating to mass-test the at-risk population, and supplement until they're above 30 ng/ml.

[0] https://news.ycombinator.com/item?id=24410547