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This transcript has been edited for clarity.
Welcome Impact factor, Your weekly commentary on new medical research. Dr. F. Perry Wilson, Yale University School of Medicine.
I have a little love-hate relationship Vitamin D..
A quick search on my blog will show how I asked the link between Vitamin D and multiple sclerosis, Kidney disease, schizophrenia, waterfall, And childhood education.
Therefore, it is not surprising that vitamin D will reappear in the age of COVID.I was intrigued when Dr. Anthony Fauci, a calm and responsible voice, even during this pandemic, made his report. Personal use of vitamin D..Vitamin D was also part Presidential Cocktail Received by Trump During my stay in Walter Reed.
I decided to dig into the data here. But before that, I would like to explain why I am essentially skeptical of vitamin D research. There are two main issues:
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Low vitamin D levels are linked to So many things. Vitamin C deficiency causes scurvy — no problem.But low vitamin D is linked to everything from Alzheimer’s disease To Whooping cough.. It is the most important vitamin in the world or a substitute for other important ones.
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We tested all these interesting links through randomized trials and gave some people vitamin D and some placebo, but in most cases no effect was seen.
I feel like Charlie Brown playing soccer here. Vitamin D has burned us before. Some examples:
According to multiple observational studies, people with low levels of vitamin D Highly likely to develop cancer And Cardiovascular disease.. These were good studies and adjusted the appropriate confounding factors — the entire transaction.
It then underwent a randomized clinical trial of 26,000 patients... Neither result is affected.
Observational studies Low vitamin D levels were associated with the development of diabetes.. Then we took the exam for 2400 patients With prediabetes. Vitamin D supplementation had no effect.
Observational studies have discovered it Low vitamin D levels are associated with falls..The· Randomized controlled trial No such effect was found. (However, exercise prevented falls.)
Does Vitamin D Generally Save Life? not really.The· Women’s Health Initiative Exam Randomized 36,000 postmenopausal women to vitamin D and placebo with no life-prolonging effect.
You see, I’m not saying that Vitamin D doesn’t have that use, or that it may have some limited benefits. Randomized trials are rarely as dramatic as the observational data promise.But I can’t think of another exposure I have like that Wide discontinuity between observational and randomized data.
why?
Because your Vitamin D level is a marker of the type of life you live in and it’s really really hard to adjust. Sure, you can ask people how much sun they exercise, how diverse their diet is, and how much money they make-but these are pretty dull. It is a tool.
Yes. With all that in mind, what do we know about Vitamin D in COVID?
Just this week Journal of Clinical Endocrinology & Metabolism, We got This study From Spain, 80% of the 216 patients admitted with COVID-19 were found to have vitamin D deficiency. Only 40% of the controls were missing. Of course, Control wasn’t hospitalized. Or actually I’m sick.
Hernandez JL, et al. J Clin Endocrinol Metab. 2020.
But okay, better research.In September, 10 years ago at the time of this recording, we This study from Chicago Of the 489 patients who had previously been tested for vitamin D, those who were deficient in vitamin D were 1.77 times more likely to be infected with COVID-19.
This study at PLOS One Of the 235 inpatients, those with vitamin D levels below 30 ng / mL had a mortality rate of 20%, while those with high levels had a 9.7%. It should be pointed out that this article was flagged as “expressing concern” about the strangeness of the data.
Now, we’re doing multiple observational studies — and Anthony Fauci shouted — saying that vitamin D should be considered.
And why really? It’s cheap. It has a fairly benign side effect profile (although my nephrologist is worried about kidney stones).
However, with regard to COVID, there are multiple factors associated with low vitamin D levels. Also Related to COVID-19 infection and severity: old age, BMI, blacks, poverty, comorbidities. It’s really hard to explain all of this statistically properly.
So I’m shy about vitamin D. I love randomized controlled trials. Currently there is one. Two, if you squint.
One randomized trial This, From Spain.
A small study of 76 patients admitted with COVID-19 was randomized in a 2: 1 ratio to vitamin D +. Azithromycin + Hydroxychloroquine (don’t start) vs azithromycin + hydroxychloroquine only. Only one of the 50 people in the Vitamin D group went to the ICU. Compare it with 13 of the 26 non-vitamin D groups.
There were no deaths in the vitamin D group and two deaths in the non-vitamin D group. The non-vitamin D group is a little higher risk at baseline, more diabetic, High blood pressure.. But to be honest, what surprises me here is the effect size. Does that mean reducing the risk of entering the ICU from 50% to 2%? That’s an amazing amount. So we are in the next space: Is this a miracle drug, or is there a problem with a study we don’t know about? And lately, miracles are scarce.
To throw cold water into that study, we This, Still in preprints, used Mendel randomization to determine if vitamin D was causally associated with COVID severity in more than 400,000 individuals.
This study design compares those who are genetically predisposed to lower vitamin D levels with those who are not. It removes the lifestyle stuff from the equation.Interestingly, people who are genetically destined for low vitamin D levels Less You may be hospitalized with COVID-19 or develop a serious illness. Salt grains, etc. that have not yet been peer-reviewed.
Butler-Laport G, etc. doi.org/10.1101/2020.09.08.20190975
What is the conclusion? We know that people with low vitamin D levels are at increased risk of adverse consequences of COVID-19. It is not yet known if vitamin D supplementation will change that risk. There are some promises here, but keep in mind 400 international units, as lifestyle vitamins have burned us before.
F. Perry Wilson, MD, MSCE, is an associate professor of medicine and director of the Applied Translational Research Program at Yale University. His science communication work can be found at the Huffington Post, NPR, and here in Medscape.He tweets @methodsmanmd Hosts a repository of his communication work at www.methodsman.com..
