Vitamin D Levels Appear To Have A Role In COVID-19 Mortality

Patient data was analyzed from 10 countries which revealed a correlation between low levels of vitamin D and hyperactive immune systems; vitamin D strengthens innate immunity and prevents overactive immune responses and these findings may help to explain several mysteries including why children are unlikely to die from this disease. 

The research team led by Northwestern University conducted a statistical analysis of data from clinics and hospitals across America, Spain, Switzerland, France, Germany, Iran, Italy, South Korea, China, and the UK; patients residing in countries with high COVID-19 mortality rates were noted to have had lower levels of vitamin D compared to those in countries that were not as severely affected. 

"While I think it is important for people to know that vitamin D deficiency might play a role in mortality, we don't need to push vitamin D on everybody," said Northwestern's Vadim Backman, who led the research. "This needs further study, and I hope our work will stimulate interest in this area. The data also may illuminate the mechanism of mortality, which, if proven, could lead to new therapeutic targets."

Inspired to examine the unexplained differences in COVID-19 mortality rates from country to country with some suggesting it was due to age distributions, testing rates, different strains of the virus, or differences in healthcare the team remained skeptical of those hypotheses and looked for a common denominator. 

"None of these factors appears to play a significant role," Backman said. "The healthcare system in northern Italy is one of the best in the world. Differences in mortality exist even if one looks across the same age group. And, while the restrictions on testing do indeed vary, the disparities in mortality still exist even when we looked at countries or populations for which similar testing rates apply.” "Instead, we saw a significant correlation with vitamin D deficiency.”

Analyzing publicly available patient data from the various countries around the globe allowed the team to discover the strong correlation between vitamin D levels and the cytokine storm caused by the overactive immune system, as well as a correlation between vitamin D deficiency and the increased mortality rate. 

"Cytokine storm can severely damage lungs and lead to acute respiratory distress syndrome and death in patients," said first author Ali Daneshkhah. "This is what seems to kill a majority of COVID-19 patients, not the destruction of the lungs by the virus itself. It is the complications from the misdirected fire from the immune system."

This is where vitamin D is believed to play a key role, as not only does it boost the innate immune systems, it also prevents the immune system from becoming dangerously over active; meaning that maintaining healthy levels of vitamin D could protect patients from severe complications which may include death from COVID-19. 

"Our analysis shows that it might be as high as cutting the mortality rate in half," Backman said. "It will not prevent a patient from contracting the virus, but it may reduce complications and prevent death in those who are infected."

This correlation may explain why childrens are less likely to die from this disease, as they don’t have a fully developed acquired immune system which is the immune system’s second line of defense and is more likely to overreact. "Children primarily rely on their innate immune system," Backman said. "This may explain why their mortality rate is lower."

The researchers caution that this does not mean that everyone needs to start hoarding vitamin D supplements, especially those without a known deficiency. All one needs to do to boost vitamin D levels is to spend about 10 to 30 minutes a day in direct sunlight a few times per week, which is free. Also it is important not to take excessive doses of vitamin D supplements which could have some negative side effects. Backman suggests that more research is required to determine the protective effects of vitamin D against COVID-19. 

"It is hard to say which dose is most beneficial for COVID-19," Backman said. "However, it is clear that vitamin D deficiency is harmful, and it can be easily addressed with appropriate supplementation. This might be another key to helping protect vulnerable populations, such as African-American and elderly patients, who have a prevalence of vitamin D deficiency."