Vitamin D appears to play a role in COVID-19 mortality rate

Patients with severe vitamin D deficiency are twice as likely to have serious complications up to death

After studying global data on the pandemic of the novel coronavirus (COVID-19), researchers have discovered a strong correlation between severe vitamin D deficiency and mortality rates.

Led by Northwestern University, a research team conducted a statistical analysis of data from hospitals and clinics in China, France, Germany, Italy, Iran, South Korea, Spain, Switzerland, the United Kingdom (UK) and the United States.

The researchers found that patients from countries with a high COVID-19 mortality rate, such as Italy, Spain, and the United Kingdom, had lower levels of vitamin D than patients in countries that were not as affected.

That doesn’t mean everyone – especially those who don’t have a known deficiency – will have to start hoarding supplements, the researchers warn.

“While I think it’s important that people know that vitamin D deficiency could play a role in mortality, we don’t have to impose vitamin D on everyone,” said Vadim Backman of Northwestern, who led the research. “This needs to be further investigated and I hope that our work will arouse interest in this area. The data could also shed light on the mortality mechanism which, if proven, could lead to new therapeutic objectives”.

Backman and his team were encouraged to study vitamin D levels after finding unexplained differences in the COVID-19 mortality rate from country to country. Some people hypothesized that differences in the quality of health care, population age distribution, test rates, or different ancestry of the coronavirus could be responsible. Backman, however, remained skeptical.

“None of these factors seem to play a significant role,” Backman said. “The health system in northern Italy is one of the best in the world. Even if you look at the same age group, there are differences in mortality. And while the limitations of testing are indeed different, the differences in mortality persist even when looking at countries or populations that have similar test rates.”

“Instead, we saw a significant association with vitamin D deficiency,” he explains.

By analyzing publicly available patient data from around the world, Backman and his team discovered a strong correlation between vitamin D levels and the cytokine storm – a hyper-inflammatory condition caused by an overactive immune system – as well as a correlation between vitamin D deficiency and mortality.

“A cytokine storm can severely damage the lungs and lead to acute respiratory distress syndrome and death in patients,” said Daneshkhah, co-author of the study. “The majority of COVID-19 patients seem to die from this, not from the destruction of the lungs by the virus itself. It is the complications of the misguided fire of the immune system”.

This is where vitamin D plays an important role, according to Backman. Vitamin D not only strengthens our innate immune system, but also prevents our immune system from becoming dangerously overactive. This means that a healthy vitamin D level could protect patients from serious complications, including death, from COVID-19.”

“Our analysis shows that adequate vitamin D supply could lead to a halving of the rate of slackness,” Backman said. “Vitamin D will not protect a patient from getting infected with the virus, but it can avoid complications and prevent the death of those infected.”

Backman said this connection could help explain the many mysteries surrounding COVID-19, such as why children die less often. Children do not yet have a fully developed immune system, which means that it cannot overreact to the virus.

“Children are primarily dependent on their innate immune system,” Backman said. “That could explain why their mortality rate is lower.”

Backman carefully points out that people should not take excessive doses of vitamin D, which could be associated with negative side effects. He said much more research needs to be done to know how vitamin D can be most effectively used to protect against COVID-19 complications.

“It’s hard to tell which dose is most beneficial for COVID-19,” Backman said. “However, it is clear that a vitamin D deficiency is harmful and can be easily corrected by appropriate supplementation. This could be another key to protecting vulnerable populations, such as African-Americans and older patients, who often have vitamin D deficiency.