Vitamin
D appears to play role in COVID-19 mortality rates
After studying global
data from the novel coronavirus (COVID-19) pandemic, researchers have
discovered a strong correlation between severe vitamin D deficiency and
mortality rates.
Led by Northwestern
University, the research team conducted a statistical analysis of data from
hospitals and clinics across China, France, Germany, Italy, Iran, South Korea,
Spain, Switzerland, the United Kingdom (UK) and the United States.
The researchers noted
that patients from countries with high COVID-19 mortality rates, such as Italy,
Spain and the UK, had lower levels of vitamin D compared to
patients in countries that were not as severely affected.
This does not mean
that everyone—especially those without a known deficiency—needs to start
hoarding supplements, the researchers caution.
"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."
The research is
available on medRxiv, a preprint server for health sciences.
Backman is the Walter
Dill Scott Professor of Biomedical Engineering at Northwestern's McCormick
School of Engineering. Ali Daneshkhah, a postdoctoral research associate in
Backman's laboratory, is the paper's first author.
Backman and his team
were inspired to examine vitamin D levels after noticing unexplained
differences in COVID-19 mortality rates from
country to country.
Some people hypothesized that differences in healthcare quality, age distributions in population, testing rates or different strains of the coronavirus might be responsible. But Backman remained skeptical.
Some people hypothesized that differences in healthcare quality, age distributions in population, testing rates or different strains of the coronavirus might be responsible. But Backman remained skeptical.
"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.
"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," he said.
By analyzing publicly available
patient data from around the globe, Backman and his team discovered a strong
correlation between vitamin D levels and cytokine storm—a hyperinflammatory
condition caused by an overactive
immune system—as well as a correlation between vitamin D deficiency
and mortality.
"Cytokine storm
can severely damage lungs and lead to acute
respiratory distress syndrome and death in patients,"
Daneshkhah said. "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 exactly where
Backman believes vitamin D plays a major role. Not only does vitamin D enhance
our innate immune systems, it also prevents our immune systems from becoming
dangerously overactive.
This means that having healthy levels of vitamin D could protect patients against severe complications, including death, from COVID-19.
This means that having healthy levels of vitamin D could protect patients against severe complications, including 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."
Backman said this
correlation might help explain the many mysteries surrounding COVID-19, such as
why children are less likely to die. Children do not yet have a fully developed
acquired immune system, which is the immune system's second line of defense and
more likely to overreact.
"Children
primarily rely on their innate immune system," Backman said. "This
may explain why their mortality rate
is lower."
Backman is careful to
note that people should not take excessive doses of vitamin D, which might come
with negative side effects. He said the subject needs much more research to
know how vitamin D could be used most effectively to protect against COVID-19
complications.
"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."
Explore further
More information: Ali Daneshkhah et al. The Possible Role
of Vitamin D in Suppressing Cytokine Storm and Associated Mortality in COVID-19
Patients, MEDRXIV (2020). DOI:
10.1101/2020.04.08.20058578
