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People always jumps to “it must be poverty!” when the Vitamin D thing comes up. There is a strong correlation between Vitamin D levels and COVID-19 outcome, re

People always jumps to “it must be poverty!” when the Vitamin D thing comes up. There is a strong correlation between Vitamin D levels and COVID-19 outcome, regardless of skin color. Independently, there is a strong correlation between having low Vitamin D levels and living in an environment to which dark skin is not adapted to. That alone should be enough to raise some caution, there is no need to wait for better data because Vitamin D supplementation is in order either way. Unfortunately, the media is mostly silent on this, likely because it wants yet another social justice narrative instead.

vinay427 6y ago
> Independently, there is a strong correlation between having low Vitamin D levels and living in an environment to which dark skin is not adapted to. Honest question: what skin color is actually adapted to western Europe or much of North America? Virtually everyone I know with a lighter skin tone needs to apply sunscreen for any outdoor activity to avoid rapid sunburns, and virtually everyone I know with a darker skin tone (jokingly or not) suspects they have a Vitamin D deficiency.
- gridlockd 6y ago
  There is no one such skin color for the latitude range you are describing. Just look at the “average” skin color of whatever ethnicity has been in a particular environment for tens of thousands of years. Native Americans clearly have darker skin than Anglosaxons. Also, much of western Europe has been colonized by peoples that previously spent thousands of years up further north. The weather in Britain is different from France, and so forth.
DanBC 6y ago
> There is a strong correlation between Vitamin D levels and COVID-19 outcome, They didn't adjust for confounders like BMI or poverty. https://www.nice.org.uk/advice/es28/chapter/Factors-for-decision-making https://www.nice.org.uk/advice/es28/chapter/Factors-for-deci... > Evidence was from 5 published studies in peer-reviewed journals. One observational cohort study (D'Avolio et al. 2020), 3 observational prognostic studies involving published data sets using correlation or regression (Hastie et al. 2020, Ilie et al. 2020 and Laird et al. 2020) and 1 case-control survey (Fasano et al. 2020) looked retrospectively at the association between vitamin D status and development of COVID‑19. None of the studies were intervention trials of vitamin D supplementation for the prevention or treatment of COVID‑19. > Four of the studies found an association or correlation between a lower vitamin D status and subsequent development of COVID‑19. However, confounders such as body mass index (BMI) or underlying health conditions, which may have independent correlations with vitamin D status or COVID‑19, were not adjusted for (D'Avolio et al. 2020, Fasano et al. 2020, Ilie et al. 2020 and Laird et al. 2020). Vitamin D status was based on serum 25‑hydroxyvitamin D (25(OH)D) levels in 3 studies and the proportion of participants taking a vitamin D supplement in 1 study. The largest UK study (Hastie et al. 2020) found an association between vitamin D status and COVID‑19 only in a univariable analysis (with this single potential causative factor). Importantly, no causal relationship between vitamin D status and COVID‑19 was found after adjustment for confounders such as comorbidity, socio-demographics, ethnicity, BMI and other baseline factors.
- thu2111 6y ago
  Is it valid to treat ethnicity as a confounder for vitamin D given that the belief is dark skin colour in northern climates results in lower vitamin D?
- gridlockd 6y ago
  "The largest UK study (Hastie et al. 2020) found an association between vitamin D status and COVID‑19 only in a univariable analysis (with this single potential causative factor). Importantly, no causal relationship between vitamin D status and COVID‑19 was found after adjustment for confounders such as comorbidity, socio-demographics, ethnicity, BMI and other baseline factors." A couple of problems with interpreting that study: First, it only looks at infections, not course of infection. The million-dollar question is not whether Vitamin D prevents an infection altogether, but how high the risk for a severe course of COVID-19 is, given a Vitamin-D deficiency. Secondly, it adjusts for ethnicity and the "Townshend deprivation index" as a proxy for socio-demographics. You have to look at the huge impact of being classified as "black" (i.e. very dark skin color), and the large impact of being classified as "south asian" (likely moderately dark skin color). No other factor besides "poor health" even comes close. These people are largely Vitamin-D deficient, so by controlling for that factor, you are implicitly lowering the impact of Vitamin-D. It's like saying "Oh yeah your Vitamin-D levels are low but really the problem is that you're black". If you look at the controlled numbers, being insufficient in Vitamin-D becomes protective (OR ~= 0.9), which doesn't make any sense. "Townshend deprivation" measures household overcrowding and lack of access to a car, which are obviously factors that increase the risk of contracting any viral infection. Again, this shouldn't be controlled for in order to answer the question. Of course a single-variate analysis is not enough, because many diseases are causal for low Vitamin-D levels, but a multi-variate analysis with too many variables isn't meaningful.

vinay427 6y ago

> Independently, there is a strong correlation between having low Vitamin D levels and living in an environment to which dark skin is not adapted to. Honest question: what skin color is actually adapted to western Europe or much of North America? Virtually everyone I know with a lighter skin tone needs to apply sunscreen for any outdoor activity to avoid rapid sunburns, and virtually everyone I know with a darker skin tone (jokingly or not) suspects they have a Vitamin D deficiency.

gridlockd 6y ago
There is no one such skin color for the latitude range you are describing. Just look at the “average” skin color of whatever ethnicity has been in a particular environment for tens of thousands of years. Native Americans clearly have darker skin than Anglosaxons. Also, much of western Europe has been colonized by peoples that previously spent thousands of years up further north. The weather in Britain is different from France, and so forth.

DanBC 6y ago

> There is a strong correlation between Vitamin D levels and COVID-19 outcome, They didn't adjust for confounders like BMI or poverty. https://www.nice.org.uk/advice/es28/chapter/Factors-for-decision-making https://www.nice.org.uk/advice/es28/chapter/Factors-for-deci... > Evidence was from 5 published studies in peer-reviewed journals. One observational cohort study (D'Avolio et al. 2020), 3 observational prognostic studies involving published data sets using correlation or regression (Hastie et al. 2020, Ilie et al. 2020 and Laird et al. 2020) and 1 case-control survey (Fasano et al. 2020) looked retrospectively at the association between vitamin D status and development of COVID‑19. None of the studies were intervention trials of vitamin D supplementation for the prevention or treatment of COVID‑19. > Four of the studies found an association or correlation between a lower vitamin D status and subsequent development of COVID‑19. However, confounders such as body mass index (BMI) or underlying health conditions, which may have independent correlations with vitamin D status or COVID‑19, were not adjusted for (D'Avolio et al. 2020, Fasano et al. 2020, Ilie et al. 2020 and Laird et al. 2020). Vitamin D status was based on serum 25‑hydroxyvitamin D (25(OH)D) levels in 3 studies and the proportion of participants taking a vitamin D supplement in 1 study. The largest UK study (Hastie et al. 2020) found an association between vitamin D status and COVID‑19 only in a univariable analysis (with this single potential causative factor). Importantly, no causal relationship between vitamin D status and COVID‑19 was found after adjustment for confounders such as comorbidity, socio-demographics, ethnicity, BMI and other baseline factors.

thu2111 6y ago
Is it valid to treat ethnicity as a confounder for vitamin D given that the belief is dark skin colour in northern climates results in lower vitamin D?
gridlockd 6y ago
"The largest UK study (Hastie et al. 2020) found an association between vitamin D status and COVID‑19 only in a univariable analysis (with this single potential causative factor). Importantly, no causal relationship between vitamin D status and COVID‑19 was found after adjustment for confounders such as comorbidity, socio-demographics, ethnicity, BMI and other baseline factors." A couple of problems with interpreting that study: First, it only looks at infections, not course of infection. The million-dollar question is not whether Vitamin D prevents an infection altogether, but how high the risk for a severe course of COVID-19 is, given a Vitamin-D deficiency. Secondly, it adjusts for ethnicity and the "Townshend deprivation index" as a proxy for socio-demographics. You have to look at the huge impact of being classified as "black" (i.e. very dark skin color), and the large impact of being classified as "south asian" (likely moderately dark skin color). No other factor besides "poor health" even comes close. These people are largely Vitamin-D deficient, so by controlling for that factor, you are implicitly lowering the impact of Vitamin-D. It's like saying "Oh yeah your Vitamin-D levels are low but really the problem is that you're black". If you look at the controlled numbers, being insufficient in Vitamin-D becomes protective (OR ~= 0.9), which doesn't make any sense. "Townshend deprivation" measures household overcrowding and lack of access to a car, which are obviously factors that increase the risk of contracting any viral infection. Again, this shouldn't be controlled for in order to answer the question. Of course a single-variate analysis is not enough, because many diseases are causal for low Vitamin-D levels, but a multi-variate analysis with too many variables isn't meaningful.