The association between low vitamin D levels and more severe COVID-19 outcomes could be partially explained by the sunshine vitamin’s effect on underlying conditions that increase an individual’s risk of severe illness from the novel coronavirus, according to a study out of Germany.
The research examined 30 studies and 53,000 patients and showed the risk of severe outcomes is significantly higher in patients with low vitamin D levels. Vitamin D is known to “play an essential role in the immune system,” and deficiency has been specifically related to many conditions that are complicating factors for COVID-19 patients. These include cardiovascular diseases, high blood pressure, diabetes, chronic kidney disease and respiratory diseases.
“These diseases in particular are often associated with a vitamin D deficiency. This has consequences for the course of Covid 19 disease,” the study says (translated).
Because vitamin D levels tend to be lower in older individuals, deficiency could also play a role in worse outcomes for patients older than 60. “The most important source of vitamin D is the formation in the skin by sunlight, and it only works to a limited extent in old age,” explains study author Dr. Hans-Konrad Biesalski.
With these findings, the researchers also question the implications of measures put in place to limit the spread of COVID-19 that lead to people spending less time in the sun. “Much more attention should be paid to the importance of vitamin D status for the development and course of the disease. Particularly in the methods used to control the pandemic (lockdown), the skin’s natural vitamin D synthesis is reduced when people have few opportunities to be exposed to the sun,” the study says. “The short half-lives of the vitamin therefore make an increasing vitamin D deficiency more likely.”