Very recently an interesting study was released in PLOS ONE journal regarding the association of vitamin D3 levels and severe COVID-19 disease. Essentially, this was a retrospective analysis of 253 people in an Israeli hospital between April 7th 2020- February 4th 2021 who had on file pre-infection vitamin d levels that were measured 14-730 days prior to a positive PCR test (infection). Researchers looked to compared vitamin D status of participants with severity of COVID-19.
In this publication you will learn about two things:
Data from the new peer reviewed Vitamin D study posted in PLOS ONE journal
If vitamin D really helps protect people from severe COVID-19
The data
All and all, the study clearly illuminated severity of COVID-19 disease as either mild, moderate, severe, or critical based on levels of vitamin D of people stratified by age, sex, and comorbidities. The particulars will be broken down in bullet points below:
N= 253 (total of individuals studied)
Normal vitamin D level is around 40 ng/mL
Mortality with sufficient vitamin D (>40 ng/mL) was 2.3% or 6 people
Mortality with deficient vitamin D (<40 ng/mL) was 25.6% or 65 people
Severe or critical disease occurred in 87.4% or 76 out of 87 individuals with vitamin d status <20 ng/mL
Mild or moderate disease occurred in 34.3% or 57 out of 166 individuals with vitamin d status <20 ng/mL
Patients with vitamin D deficiency (<20 ng/mL) were 14 times more likely to experience severe or critical disease compared to patient with normal vitamin D levels (≥40 ng/mL)
Of course another major risk factor is age with the median of those suffering mild/moderate disease being 58.9 years old, and 72.7 for severe/critical disease
As you can see, the data clearly shows some interesting information. First, there’s a salient correlation between low vitamin D status and mortality with a significant p value of p<0.001 indicating a significant finding. P, otherwise known as P-value is the level of statistical significance a particular finding is. Specifically, a value of ≤ 0.05 is considered significant.
Second, severe or critical disease was seen in 87.4% of those with vitamin D levels <20 ng/mL, while only 34.3% with low vitamin D experienced mild or moderate disease. The former revealed a significant P-value P<0.001.
Third, age played a significant factor regardless of vitamin D status. To explain, the majority of mild/moderate and severe/critical cases were over 58 years old. Stratified by severity: the average age of individuals that suffered mild/moderate cases were 58.9, while the average age of individuals that suffered severe/critical cases were 72.7 years old. That said, one could deduce, age is also a major risk factor. However, that coupled with a vitamin D deficiency seems to create a more significant danger.
All of the above bullet information summarized the key points of this vitamin D study. Next, we will explore some graphs that researchers created for this paper. Keep scrolling down to find them 👇.
Graphs
The graphs below do a good job of pointing out 2 major findings. The first about severe/critical disease, and second about age. Both equally as important and present a similar undertone regarding COVID-19 disease that will be covered in a following paragraph.
To begin, direct your eyes to FIG. 1 📸 below. This graph gives an excellent visual of severity of disease vs. vitamin D status. In other words, the left hand side of this box and whisker plot is a measurement of vitamin D in nanograms per milliliter. On the other hand, the X axis, or bottom line, is severity of disease expressed as mild, moderate, severe, or critical. That said, Let’s talk about mild & critical disease.
As you can see from the graph, the difference between the spacing of mild and severe boxes is remarkable. As a consequence, such contrast provides the visual for an OR=14. You see, an OR is an odds ratio, it quantifies the strength of two events. For instance, the OR (odds ratio) of a patient with a vitamin D level under 40 to experience severe or critical disease compared to a patient with normal levels is 14. Said differently, in this study, patients with a vitamin D deficiency (<20 ng/mL) were 14 times more likely to experience severe or critical disease compared to patient with normal vitamin D levels. Now look at the graph and you can clearly see that distinction.
FIG. 1 📸
Moving on to FIG. 2 📸, the main point is regardless of vitamin D status, age is a huge factor when looking at severe disease from COVID. Two graphs below make the case.
As you can see by comparing both of the graphs below, those 50 and under were affected less by lower vitamin D levels than those 50-65. In other words, vitamin D status certainly matters however it’s seems like a double whammy for some if they are both older and vitamin D deficient. Truly though, that remains unknown because there’s not a good control group in this study.
FIG. 2 📸
Now let’s talk about a similar undertone between both graphs. Of course, I did elude to it in the previous paragraph, but only for a moment. That is, age. Simply put, anyone interpreting this data must understand that vitamin D levels of individuals suffering severe/critical disease happen to be older. Said another way, a majority of older people in this study seem to suffer severe/critical disease regardless of vitamin D status although they did happen to have lower levels on average.
Confounders/problems with the data
Sample size wasn’t large enough. There were only 253 total individuals in this data. Such a minuscule number of participants doesn’t often reveal the true implications that would be seen on a population level
Study doesn’t take into account vaccination status. Specifically, the data looked at individuals between April 7th 2020- February 4th 2021. Vaccines were being rolled out in December of 2020. As you know, vaccination gives people protection against severe disease. So, not accounting for vaccination status equally in both groups makes the data unreliable
Vitamin D was measured 14-730 days before positive test. That is a huge problem because someones level can easily change within 30-60 days, let alone 730 days. That said, by the time the person gets sick their previously measured vitamin D levels could have plummeted. Therefore, testing done in this study was inaccurate and no conclusions can accurately be drawn about the protective nature of vitamin d against COVID-19.
A retrospective analysis like this doesn’t historically yield great results because they allow the surveyor to pick endpoints. The gold standard is an RCT (randomized controlled trial). So, one control group/placebo against a treatment group + pre-defined endpoints is needed for further judgement to be made about vitamin D’s protection against severe disease.
So, will vitamin D protect people from severe disease?
Sadly, this study can’t prove that. But there is a lot of other data to support efficacy for vitamin D. Now, it should be stated that vitamin D is something many people in the United States are deficient in for two major reason.
One, it’s impossible to get enough of it through a standard American diet. Two, people are not spending enough time in the sun for many reasons. Maybe because they spend too much time indoors working, or live in an area that doesn’t see much sun.
As the difficulty to meet adequate vitamin D consumption is a reality for many, they often chose to supplement. Notably, the correct form must be taken and that is D3 (cholecalciferol). Purchasing vitamin d, or vitamin D2 won’t work well.
Importantly, there are studies to show that vitamin D can help modulate the immune system in people who have auto immune diseases. Here’s a link to a BMJ article recently published.
Considering all the variables, vitamin D did not provide any increased protection against severe COVID-19 in this study. Be that as it may, have you checked your vitamin D levels lately?
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