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Comment by JshWright | Hacker News Reader

You're missing the third option:

People who are more likely to be hospitalized due to COVID are also more likely to be deficient in vitamin D. There doesn't have to be a causal relationship at all.

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The level of evidence isn't great yet, but its highly likely that Vitamin D can help modulate the immune system. There is a retrospective study showing a difference between patients that got Vitamin D and those that didn't (can't find the link, unfortunately), and

there is a small Spanish trial of 75 people where 50 got Vitamin D and 25 did not; in the group that did, 1 person needed oxygen whereas in the other group 12 people needed oxygen and one died - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7456194/

I suppose there's even a fourth option:

People who are more likely to be hospitalized are also more likely to be deficient in vitamin D.

The control group seemed to be a healthy population sample, but hospitals are not a pool of healthy people. How about a hospital sample instead of a population sample?

Or maybe a 5th option: "People who are staying socially isolated spend less time in the sun, so the population has become more vitamin D deficient".

I know that I'm spending less time outdoors than I used to -- no more outdoor picnics/parties, no beach time this summer, I'm not even biking as much as I used to.

But that actually contradicts logic a bit.

I would expect those that are leaving their homes are both more exposed to sun/less deficient in vitamin D and also more likely to contract COVID.

And likewise, those that are staying home are more deficient, but less likely to contract COVID.

Unless social distancing in practice is not uniformly effective, and a large number of people both stay indoors to social distance, and are still quite likely to catch COVID because they are indoors with people who don't socially distance.

Plus being indoors means a confined space with less airflow, less air volume, and almost no upper range UV sunlight compared to being outdoors; these all are significant factors for likelihood of covid spreading.

Uhm, that seems a tad convoluted. Are you saying people that socially distance themselves are more likely to contract Covid-19 because the ones that don't are so often outside that they will contract it less probably?

And further, that's not the definition of social distancing. This would obviously include indoors. I won't sit at my kitchen table with the postman for a coffee while I am avoiding public gatherings.

I am sorry, my sarcasm-radar is quite broken. Are you joking?

Or a 6th option: Over 80% of people have Vitamin D deficiency, and the incoming Covid-19 patient population was not different in this regard.

This isn't really a 7th option because it overlaps with some of the previously mentioned ones, but perhaps individuals who don't supplement with vitamin D are more likely to catch Covid-19 because they also don't take other precautions like wearing masks.

Anecdotally it seems those I know who are most concerned about Covid-19 know all about the possible link with vitamin D and are taking supplements while also being careful by wearing masks, sanitising etc.

Recently I keep seeing references to protecting oneself by wearing a mask.

When did the narrative shift from "wear a mask to limit transmission to others in case you might be infected and asymptomatic" to "wear a mask to protect yourself"?

Assuming we are talking about the usual surgical / cloth masks here (not N95 etc), is there any evidence that they protect the wearer?

We all know that mask wearing and the science (or lack of it) to support it has become ridiculously politicised, but I'm curious if there's any evidence behind this particular shift.

There is some weak evidence that wearing a cloth mask might protect yourself:

https://www.businessinsider.com/56-got-coronavirus-south-kor...

https://www.npr.org/sections/health-shots/2020/06/21/8808322...

There were results from studies showing weak effects of self-protection even by "simple" surgical masks a few months ago.

Evidence seems to indicate there is such an effect - and contradicting the initial assumption that there isn't.

I don't know of any post-COVID studies, but most studies pre-COVID show around 40% of the population being deficient both in the USA and Europe.

This, and as someone who recently found out that they have a severe vitamin D deficiency, I was surprised to know that it's not something normally checked for in yearly blood tests.

Check the videos on Dr John Campbell's (PhD nurse educator in the UK) web site. The UK national health service has good medical records that can be cross-referenced and cross-linked every which way. Someone examined the historical records, found a reasonably large number of persons who had vitamin D levels checked before the pandemic, and checked those statistics vs the Covid-19 experience of the same people. (Imagine living in a country where that could happen.) IIRC, this did find some benefits wrt COVID-19 of not having a very low vitamin D level.

That would be incorrect. Even though the causal vector is unknown, the correlation is well established.

How would this produce the study result?

Are people that isolate more likely to get hospitalized with Covid-19 than those that do not?

Maybe Vitamin D reduces all-cause hospitalization

Or maybe low vitamin D levels are a symptom of the same "root cause" that leads to higher risk for Covid-19 and just supplementing vitamin D does not do anything to lower the latter.

Those vitamin D level statistics have been floating around for months. What's missing is a placebo-controlled study to see whether supplementation would make a difference. But that involves more than just clicking a bit of statistics.

That study is absolutely not missing, and it says exactly what you'd expect it to[0]. It's even being tested as an active treatment[1]. In fact, that study was also done with Influenza[2] and other lung borne ailments as well. It pretty obviously works, has tremendous explanatory power in the observed patterns of disease, and the fact that no government has sanctioned its use or its mass production ... well, I guess modernity kind of sucks. Better to pimp useless expensive garbage pharma companies can turn a profit on.

[0]https://clinicaltrials.gov/ct2/show/NCT04536298

[1] https://clinicaltrials.gov/ct2/show/NCT04385940

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4463890/#:~:tex....

Excellent, thank you.

Unfortunately, [0] and [1] are still ongoing and [2] reads like a blog post of somebody ranting about a statistical error, followed by some anecdotal evidence and the demand for an actual study. There could still be something there, but summarizing all of that as "quite obviously works" is stretching it.

Maybe beeing healthy and able to go outdoors reduces all-cause hospitalization (apart from accidents)

Yeah, that's very likely actually, since the biggest risk group, the elderly, are also one of the groups with the highest levels of vitamin D deficiency.

In this study here 84% of the elderly had some amount of vitamin D deficiency (Figure 3).

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6178567/#:~:tex....

I do take Vitamin D supplements since they're cheap and available, just in case there is something to it, but I wouldn't bet on it.

There must be very well controlled groups of elderly people who after some blood test have been taking supplements and checking their vitamine D levels. I wonder how the virus is affecting this group compared with the general population of the same age. If this group were doing well, I think it would be quite conclusive, since it would show that people under treatment (and therefore with some previous health problem) are doing better than supposedly healthy people with low vitamine D values.

I do the same. Getting enough sunlight is hard during wintertime.

Vitamin D deficiency has been linked to compromised immune systems, depression, rickets and several other things. More research is needed within several of those areas, but I believe it to be safe to assume that supplementing with vitamin D is good for you if you're deficient. If not, well, it's not like it's going to hurt you unless you overdo it.

I understand what you mean, but don't think your example really fits since an increase in vitamin D in either scenario would ultimately reduce the occurrences of patients showing low vitamin D levels. And this seems to be a fairly consistent finding across multiple studies that use different controls/stratification/etc.

Or do you mean people may be becoming deficient in vitamin D as a result of Covid? If so, would be interesting to know their prior vitamin D levels.

I'm not entirely sure you're replying to the correct comment, but just in case...

I mean the population of people who are more likely to be hospitalized due to COVID also happens to be the population of people that is more likely to be deficient in vit D, and neither of those things have to cause the other.

An increase in Vitamin D levels may or may not impact COVID 19 hospitalization rates.

Just like lowering ice cream sales won’t change the murder rate. Even though increased Ice cream sales is correlated with increase murder rate.

I know your point is that correlation does not mean causation (though maybe those are correlated?), however, that really makes it sound like guys like Ben & Jerry have blood on their hands.

rblatz is referring to a well known correlation: more nursery happen in summer. More ice cream gets sold in summer. Therefore, ice cream sales are correlated with murders.

This correlation is not random - it holds across geographic boundaries and time. But it is not causal - decreasing ice cream sales (By limiting supply, raising price, etc) will not reduce murders. Decreasing murders (By more police intervention, limiting arms sales) does not reDuce ice cream sales.

Similarly, vitamin D may be The ice cream analog. COVID 19 may be the murder analog, and if that’s true, we don’t yet know what summer’s analog here - could be obesity, or genetic factors, or something else. We don’t know.

typo - you put 'nursery' instead of 'murder'

Thanks, too late to fix now. DYAC, was on phone and didn't notice.

> Even though increased Ice cream sales is correlated with increase murder rate.

I thought you were kidding but no: https://slate.com/news-and-politics/2013/07/warm-weather-hom...

I doubt anyone is saying with 100% assurance this is the -cause- but that it would be worth investigating further. If they'll change FDA recommendations for the blowhard in chief, we should also consider lack of certain nutrients as possibly something to look into as well.

I recall an article a few months ago that discussed the Vitamin-D link in more depth, and a plausible mechanism was already suggested: vitamin D regulates the immune system response. People with low vitamin D levels are more likely to experience severe cytokine storms.

PDF from April 2020: https://www.medrxiv.org/content/medrxiv/early/2020/04/10/202...

The impact of Vit D in enhancing immune response (including flu and previous coronaviruses) has widely been studied and firmly established. Vit D can also suppress cytokine storm, which may substantially increase the chances of avoiding a severe case of COVID-19

^this!

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