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Nobody seems to be asking a related question: in a sunny country like Israel vitamin D deficiency should be less common, does that translate into fewer Covid-19

Nobody seems to be asking a related question: in a sunny country like Israel vitamin D deficiency should be less common, does that translate into fewer Covid-19 cases? Well, there seem to be differences between different ethnic & religious groups, but on average vitamin D deficiency seems to be less prevalent in Israel: https://pubmed.ncbi.nlm.nih.gov/28647929/ https://pubmed.ncbi.nlm.nih.gov/28647929/ However Covid-19 cases don't seem to have been lacking in Israel https://www.worldometers.info/coronavirus/country/israel/ https://www.worldometers.info/coronavirus/country/israel/

mixmastamyk 6y ago
Don’t they have a lot of old folks as well? It’s a multi-factor situation.
wk_end 6y ago
I don't see how it would mean fewer SARS-CoV-2 infections. It might mean fewer infections proceed to symptoms, hospitalizations, and death. Just from your source, their CFR is around 0.8%. That's not IFR, so it's hard to really do a serious comparison, but for the heck of it Canada's CFR is ~4.4%, Sweden's is ~5.1%, the US' is ~2.5%, Germany's is 2.2%.
- MichaelMoser123 6y ago
  Makes sense. Thank you! Is it possible to know how certain the CFR measures are? I would have guessed that the CFR depends on the test coverage and maybe other factors as well; With what degree of confidence are the CFR figures treated? however these are all countries with not too different level of health care, so that my armchair guess would be that this is a meaningful number (would have to be corrected for different age distribution, somehow)
  - wk_end 6y ago
    CFR is just confirmed deaths divided by confirmed cases. It's absolutely certain, but that's also why it's not a great basis for a serious analysis of most things. We can comfortably say the numerator is roughly correct, but the denominator is likely too low because we probably missed a lot of cases, given limited testing capacity and just how asymptomatic COVID often is. IFR is actual deaths divided by actual infections. It's the most important number, but also much harder to figure out, because the delta between confirmed cases and actual infections is, by definition, unknown. So, in context, if we look at CFRs, it looks like Israelis are 3x less likely to die from COVID than Americans. Maybe that's vitamin D, or maybe instead Israel tested and identified every single person with COVID, whereas America missed two for very case they identified. If we could instead see the IFRs in that case, they'd actually be roughly the same, and it'd turn out (all other things being equal) that vitamin D was irrelevant.
    - MichaelMoser123 6y ago
      that would have to be corrected for different age distributions, somehow. But yes, such a big difference seems to make some sense.
stjohnswarts 6y ago
there are likely too many variables to control for just by taking people off the street. If you had universal testing of every citizen and could then compare that across countries with varying level of sunlight (say Norway vs Israel) then you could probably make a great educated guess.
colechristensen 6y ago
People who live in sunnier places tend to have darker skin which limits vitamin D production. There is a high correlation between skin pigmentation and the average UV index of a location.
baxtr 6y ago
You’d need to correct for age distribution, which I guess is difficult to do. Many sunny countries have younger populations than for example Western Europe
DoreenMichele 6y ago
In some conservative Muslim countries -- often found in sunny areas -- girls have high rates of vitamin D deficiency because of the practice of being very covered up anytime they leave the house. I read some book authored by a woman from such a country and one of the details that stood out was a remark she made about how every woman who gets out of those countries remarks on how wonderful it is be able to just go outside without a veil and feel the sun on your skin. Plus, as others have noted, some of those countries have very young populations and darker skin tones of local inhabitants impacts vitamin D production as well. There are really going to be a lot of factors involved.
- dependsontheq 6y ago
  Israel is not a conservative Muslim country.
  - DoreenMichele 6y ago
    Yeah, no one said it was.
kesor 6y ago
You are assuming that in a sunny country less people have vitamin D deficiency. Why would that hold true? Yes, vitamin D is "made" by exposing skin to sun. But what about those people who have some kind of metabolic problem and are thus not making vit-D as much even when exposed to sun? And how about a country, like Israel, where it is SO sunny and hot outside that most people are hiding from it because they are afraid of skin cancer and such?
javitury 6y ago
That's a good point. The association between vitamine D and coronavirus could be hidding a confounding variable: time spent indoors. Spending time indoors increases the risk of contagion and viral load. Also it's correlated with lower sun exposure and lower vitamine D levels.
JumpCrisscross 6y ago
> in a sunny country like Israel vitamin D deficiency should be less common, does that translate into fewer Covid-19 cases? The first time I drove through Phoenix I was confused by the number of tanning salons. After living there for a few years, I learned the extreme heat drives people indoors and into cars. The same is true in e.g. Dubai.
stareatgoats 6y ago
There was a 2010 study on this [0], using a small but supposedly representative sample of the Israeli population (195 people). I can't vouch for the quality, but the study found that almost 80% had vitamin-D insufficiency, including 27% that were deficient. [0] https://www.ima.org.il/FilesUploadPublic/IMAJ/0/40/20233.pdf https://www.ima.org.il/FilesUploadPublic/IMAJ/0/40/20233.pdf
reuven 6y ago
There was a newspaper article (in Israel, where I live) on this subject. It noted that the two populations most mostly likely to suffer from covid are Haredim (ultra-Orthodox Jews) and Arabs, both of which tend to dress conservatively, and the latter of which have darker skin than the average Israeli, and thus might have less vitamin D in their systems. Of course, these two populations also tend to be poorer and have larger families living together, so there are other factors to consider as well. For example, Israelis are told to worry about skin cancer, and thus tend to use sunblock when going out in the summer. Which removes the chance of serious vitamin D generation, from what I understand. I find the discussion of vitamin D to be very interesting, but it feels like we need a few more studies to determine whether this is the big one. But the more discussions I see, the more I think it might actually explain quite a lot.
- golergka 6y ago
  > latter of which have darker skin than the average Israeli Do they? I'm pretty sure that average israeli is mizrahi.
  - reuven 6y ago
    A good point; I'm not sure. But Moroccans are typically not that dark. I'm guessing (and this is truly a guess) that if vitamin D and/or exposure to sun has something to do with it, then skin tone is a factor but might well be outweighed by the others.
- MichaelMoser123 6y ago
  Your profile says that we are both from the same town, the world is a small place! I would think that an HN meetup would be appropriate; my email is in my profile if you are interested.
smaryjerry 6y ago
Cases are not the factor recognized, what is being correlated is the severity and hospitalizations. A case without hospitalization is very different so a better number to evaluate health would be hospitalizations, especially extended hospitalizations and deaths. Fauci has said 20-40 percent of people who contract the virus may be asymptomatic. That means those people don’t even sniffle once and are not getting tested because they don’t ever get sick. This was shown early on in controlled groups on a military ship where they tested full populations even those not sick and found 40 percent of the people who had the virus were asymptomatic.

mixmastamyk 6y ago

Don’t they have a lot of old folks as well? It’s a multi-factor situation.

wk_end 6y ago

I don't see how it would mean fewer SARS-CoV-2 infections. It might mean fewer infections proceed to symptoms, hospitalizations, and death. Just from your source, their CFR is around 0.8%. That's not IFR, so it's hard to really do a serious comparison, but for the heck of it Canada's CFR is ~4.4%, Sweden's is ~5.1%, the US' is ~2.5%, Germany's is 2.2%.

MichaelMoser123 6y ago
Makes sense. Thank you! Is it possible to know how certain the CFR measures are? I would have guessed that the CFR depends on the test coverage and maybe other factors as well; With what degree of confidence are the CFR figures treated? however these are all countries with not too different level of health care, so that my armchair guess would be that this is a meaningful number (would have to be corrected for different age distribution, somehow)
- wk_end 6y ago
  CFR is just confirmed deaths divided by confirmed cases. It's absolutely certain, but that's also why it's not a great basis for a serious analysis of most things. We can comfortably say the numerator is roughly correct, but the denominator is likely too low because we probably missed a lot of cases, given limited testing capacity and just how asymptomatic COVID often is. IFR is actual deaths divided by actual infections. It's the most important number, but also much harder to figure out, because the delta between confirmed cases and actual infections is, by definition, unknown. So, in context, if we look at CFRs, it looks like Israelis are 3x less likely to die from COVID than Americans. Maybe that's vitamin D, or maybe instead Israel tested and identified every single person with COVID, whereas America missed two for very case they identified. If we could instead see the IFRs in that case, they'd actually be roughly the same, and it'd turn out (all other things being equal) that vitamin D was irrelevant.
  - MichaelMoser123 6y ago
    that would have to be corrected for different age distributions, somehow. But yes, such a big difference seems to make some sense.

stjohnswarts 6y ago

there are likely too many variables to control for just by taking people off the street. If you had universal testing of every citizen and could then compare that across countries with varying level of sunlight (say Norway vs Israel) then you could probably make a great educated guess.

colechristensen 6y ago

People who live in sunnier places tend to have darker skin which limits vitamin D production. There is a high correlation between skin pigmentation and the average UV index of a location.

baxtr 6y ago

You’d need to correct for age distribution, which I guess is difficult to do. Many sunny countries have younger populations than for example Western Europe

DoreenMichele 6y ago

In some conservative Muslim countries -- often found in sunny areas -- girls have high rates of vitamin D deficiency because of the practice of being very covered up anytime they leave the house. I read some book authored by a woman from such a country and one of the details that stood out was a remark she made about how every woman who gets out of those countries remarks on how wonderful it is be able to just go outside without a veil and feel the sun on your skin. Plus, as others have noted, some of those countries have very young populations and darker skin tones of local inhabitants impacts vitamin D production as well. There are really going to be a lot of factors involved.

dependsontheq 6y ago
Israel is not a conservative Muslim country.
- DoreenMichele 6y ago
  Yeah, no one said it was.

kesor 6y ago

You are assuming that in a sunny country less people have vitamin D deficiency. Why would that hold true? Yes, vitamin D is "made" by exposing skin to sun. But what about those people who have some kind of metabolic problem and are thus not making vit-D as much even when exposed to sun? And how about a country, like Israel, where it is SO sunny and hot outside that most people are hiding from it because they are afraid of skin cancer and such?

javitury 6y ago

That's a good point. The association between vitamine D and coronavirus could be hidding a confounding variable: time spent indoors. Spending time indoors increases the risk of contagion and viral load. Also it's correlated with lower sun exposure and lower vitamine D levels.

JumpCrisscross 6y ago

> in a sunny country like Israel vitamin D deficiency should be less common, does that translate into fewer Covid-19 cases? The first time I drove through Phoenix I was confused by the number of tanning salons. After living there for a few years, I learned the extreme heat drives people indoors and into cars. The same is true in e.g. Dubai.

stareatgoats 6y ago

There was a 2010 study on this [0], using a small but supposedly representative sample of the Israeli population (195 people). I can't vouch for the quality, but the study found that almost 80% had vitamin-D insufficiency, including 27% that were deficient. [0] https://www.ima.org.il/FilesUploadPublic/IMAJ/0/40/20233.pdf https://www.ima.org.il/FilesUploadPublic/IMAJ/0/40/20233.pdf

reuven 6y ago

There was a newspaper article (in Israel, where I live) on this subject. It noted that the two populations most mostly likely to suffer from covid are Haredim (ultra-Orthodox Jews) and Arabs, both of which tend to dress conservatively, and the latter of which have darker skin than the average Israeli, and thus might have less vitamin D in their systems. Of course, these two populations also tend to be poorer and have larger families living together, so there are other factors to consider as well. For example, Israelis are told to worry about skin cancer, and thus tend to use sunblock when going out in the summer. Which removes the chance of serious vitamin D generation, from what I understand. I find the discussion of vitamin D to be very interesting, but it feels like we need a few more studies to determine whether this is the big one. But the more discussions I see, the more I think it might actually explain quite a lot.

golergka 6y ago
> latter of which have darker skin than the average Israeli Do they? I'm pretty sure that average israeli is mizrahi.
- reuven 6y ago
  A good point; I'm not sure. But Moroccans are typically not that dark. I'm guessing (and this is truly a guess) that if vitamin D and/or exposure to sun has something to do with it, then skin tone is a factor but might well be outweighed by the others.
MichaelMoser123 6y ago
Your profile says that we are both from the same town, the world is a small place! I would think that an HN meetup would be appropriate; my email is in my profile if you are interested.

smaryjerry 6y ago

Cases are not the factor recognized, what is being correlated is the severity and hospitalizations. A case without hospitalization is very different so a better number to evaluate health would be hospitalizations, especially extended hospitalizations and deaths. Fauci has said 20-40 percent of people who contract the virus may be asymptomatic. That means those people don’t even sniffle once and are not getting tested because they don’t ever get sick. This was shown early on in controlled groups on a military ship where they tested full populations even those not sick and found 40 percent of the people who had the virus were asymptomatic.