Vitamin D is a fat-soluble vitamin that plays key roles in several physiological processes, including immune function. Robust evidence demonstrates links between poor vitamin D status and severe outcomes following infection with SARS-CoV-2, the virus that causes COVID-19. Now, findings from a recent study suggest that poor vitamin D status prior to infection with SARS-CoV-2 increases the risk of severe disease and/or death from COVID-19.
During an infection, vitamin D deficiency can lead to over-expression of renin (an enzyme produced in the kidneys) and subsequent activation of the renin-angiotensin-system, a critical regulator of blood pressure, inflammation, and body fluid homeostasis. Disturbances in this system can drive poor outcomes, such as acute respiratory distress syndrome and death in COVID-19. Research suggests that supplemental vitamin D during hospitalization with COVID-19 improves outcomes. Vitamin D levels may drop during a viral infection, however, so measuring pre-infection status provides a more accurate assessment of the vitamin’s protective effects.
The authors of the study reviewed the medical records of 253 patients whose vitamin D levels had been measured two weeks to two years prior to testing positive for COVID-19. They categorized the patients according to disease severity (critical, severe, moderate, or mild). They classified the patients' vitamin D status as deficient, below 20 nanograms per milliliter (ng/ml); insufficient, 20 to 29.9 ng/ml; adequate, 30-39.9 ng/ml; or high-normal, above 40 ng/mL.
They found that patients categorized as having critical or severe COVID-19 disease were 14 times more likely to have pre-infection vitamin D deficiency than patients with moderate or mild disease. Patients with vitamin D deficiency were more likely to have coexisting illnesses, such as diabetes, high blood pressure, and chronic obstructive pulmonary disease and were 11 times more likely to die from COVID-19, compared with those who had vitamin D sufficiency.
These findings suggest that pre-infection vitamin D deficiency markedly increases the risk of critical or severe disease and death in patients with COVID-19. Learn more about the importance of vitamin D in COVID-19 in this episode featuring frontline physician Dr. Roger Seheult.
The science digest is a special email we send out just twice per month to members of our premium community. It covers in-depth science on familiar FoundMyFitness related topics.
If you're interested in trying out a few issues for free, enter your email below or click here to learn more about the benefits of premium membership here.