This goal of this study is to see if levels of Vitamin D affects case rate and mortality rate of COVID-19 in European countries. It was found that with higher levels of Vitamin D, the case rate and mortality rate were lower.
In many other respiratory tract infections, Vitamin D helps to prevent more serious complications. But COVID-19 may be different because the virus interacts with ACE2 to enter the cell. Calcitriol, which is a form of Vitamin D, increases the amount of ACE2. So, higher amounts of Vitamin D might suggest a higher risk of COVID-19 infection. Stil, the researchers think that Vitamin D will protect against COVID-19 since it has that effect in other respiratory infections.
Methods and Results
This study compared average Vitamin D levels with cases of COVID-19 and deaths caused by COVID-19 in European countries. High Vitamin D levels are associated with low case rate and low death rate.
Vitamin D deficiency is defined by a level lower than 30nmol/L. The average values for the elderly population in Spain, Switzerland, and Italy are all under 30nmol/L. These countries have a high death rate in their elderly populations. Anyone worldwide can have a Vitamin D deficiency, but the levels naturally lower with age. Lifestyle and genetics also play a role in Vitamin D deficiency. This is why low Vitamin D trends are seen in different countries who eat different foods, have different activities, and have different genetics.
To confirm that Vitamin D is protective against COVID-19, we can look at this relationship in other respiratory diseases. Though Vitamin D can increase ACE2 levels and could potentially increase the infection rate of COVID-19, Vitamin D plays a big role in the immune system. Vitamin D is necessary for some white blood cells to mature. It also plays a role in the body’s ability to detect infected cells. Finally, Vitamin D helps create some of the enzymes that are toxic and can help kill diseases.
Even though SARS-CoV-2 uses ACE2 to enter the cells, studies have shown that higher levels of ACE2 actually protects against serious COVID-19 issues. In studies done on rodents, ACE2 has decreased rapidly in elderly rats compared to young and middle aged rats. ACE2 also decreased more in male rats than female rats.
The data used in this study is limited because there are many other variables involved for every country like access to testing and social distancing measures. Future studies should be done to confirm that Vitamin D is protective against COVID-19.