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News and Research: Vitamin D, COVID-19 JAMA study

Two good studies on vitamin D levels and SARS-CoV-2 have been published recently in major journals.  Both studies back up all the previous research on vitamin D and immune function.

This isn’t really new news…  Having adequate vitamin D levels is vital for good immune function – whether for COVID-19, the flu, other respiratory viruses, Dengue fever, etc.


PLOS ONE: SARS-CoV-2 positivity rates associated with circulating 25-hydroxyvitamin D levels Sept 2020

This latest vitamin D study included 191000 participants and used ‘deidentified’ test results from Quest. The participants had all had a vitamin D test within the last 12 months as well as a SARS-CoV-2 test that was run through Quest.

The results showed that low vitamin D was linked to higher rates of SARS-CoV-2 positive test results. As vitamin D levels increase, the rate of positive test results decreases, up to a point.


Things to keep in mind:

  • This study also shows that people with vitamin D level in the deficiency range (<20 ng/mL) were at a higher risk of SARS-CoV-2.
  • Older people are more likely to have vitamin D deficiency, but in this study, more younger people were SARS-CoV-2 positive (thus not skewing the results towards deficiency due to age)
  • The data showed a decrease in SARS-CoV-2 positivity rate up until vitamin D levels hit 55 ng/mL.



JAMA: Association of Vitamin D Status and Other Clinical Characteristics With COVID-19 Test Results Sept 2020

This recently published study was conducted by researchers at the University of Chicago using data on vitamin D status of patients from the previous year. There were 489 patients included in the study, and of those, 71 tested positive for the SARS-CoV-2 virus.

The results of the study showed that patients who had been deficient in vitamin D over the previous year were at an almost double risk of getting COVID-19.

A couple of things to keep in mind:

  • Vitamin D levels may change in people who already have severe COVID and are in the hospital. This study gets around that problem of causality by using the vitamin D status from a previous visit to their doctor.
  • This study was conducted during the first weeks of the COVID-19 pandemic in Chicago in March. Participants were excluded if they were taking supplemental vitamin D.
  • The study group consisted of people who were admitted to the hospital with COVID symptoms (thus more severe than the majority of people) and also health care workers.
  • Deficiency here was defined as below 20 ng/mL for 25(OH) D

About the Author:
Debbie Moon is the founder of Genetic Lifehacks. Fascinated by the connections between genes, diet, and health, her goal is to help you understand how to apply genetics to your diet and lifestyle decisions. Debbie has a BS in engineering from Colorado School of Mines and an MSc in biological sciences from Clemson University. Debbie combines an engineering mindset with a biological systems approach to help you understand how genetic differences impact your optimal health.