Adequate vitamin D levels may reduce COVID-19 complications

Hospitalized patients with the novel coronavirus (COVID-19) who were vitamin D sufficient, with a blood level of 25-hydroxyvitamin D of at least 30 ng/mL, had a significantly decreased risk for adverse clinical outcomes including becoming unconscious, hypoxia, and death, according to a new study by the Boston University School of Medicine published in the journal PLOS One. Additionally, the patients had lower blood levels of inflammatory marker C-reactive protein and higher blood levels of lymphocytes, a type of immune cell to help fight infection.

For the study, a blood sample to measure vitamin D status was taken from 235 patients who were admitted to the hospital with COVID-19. These patients were followed for clinical outcomes including clinical severity of the infection, becoming unconscious, having difficulty in breathing resulting in hypoxia, and death. The blood was also analyzed for C-reactive protein and for numbers of lymphocytes. The researchers then compared all the parameters in patients who were vitamin D deficient to those who were vitamin D sufficient.

In patients older than 40 years, the researchers said they observed that those patients who were vitamin D sufficient were 51.5 percent less likely to die from the infection compared to patients who were vitamin D deficient or insufficient with a blood level of 25-hydroxyvitamin D less than 30 ng/mL, according to the study.

Michael Holick, PhD, MD, corresponding author and professor of medicine, physiology, and biophysics and molecular medicine at the Boston University School of Medicine, said the researchers believe being vitamin D sufficient helps to fight consequences from being infected not only with COVID-19, but also other viruses causing upper respiratory tract illnesses including influenza. 

Holick said this study provides a simple and cost-effective strategy to improve one's ability to fight and reduce COVID-19's adverse clinical outcomes, including requiring ventilator support, overactive immune response leading to cytokine storm, and death.

"Because vitamin D deficiency and insufficiency is so widespread in children and adults in the United States and worldwide, especially in the winter months,” he said in a statement, “it is prudent for everyone to take a vitamin D supplement to reduce risk of being infected and having complications from COVID-19."

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