Researchers have been puzzled by differences in COVID-19 mortality rates from country to country, suspecting healthcare quality, age variations in populations, testing rates and different strains of the coronavirus might be responsible.
However, a new study based on global data, has discovered a strong correlation between severe vitamin D deficiency and mortality rates.
Led by Northwestern University in the US, the research team conducted a statistical analysis of data from hospitals and clinics across China, France, Germany, Italy, Iran, South Korea, Spain, Switzerland, the UK and the US.
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.
They cautioned that this did not mean that everyone – especially those without a known deficiency – needed to start buying and hoarding supplements.
“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 Professor 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.”
Prof. Backman explained how researchers first investigated many other factors in countries with wildly different mortality rates, such as healthcare standards and the age of populations.
“None of these factors appears to play a significant role,” he 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.”
The research team analysed publicly available patient data from around the globe, and 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,” the team reported. “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.”
Prof. Backman said that was where vitamin D played a major role, explaining that not only did vitamin D enhance our innate immune systems, it also prevented our immune systems from becoming dangerously overactive. Healthy levels of vitamin D could protect patients against severe complications, including death, from COVID-19, he said.
“Our analysis shows that it might be as high as cutting the mortality rate in half. It will not prevent a patient from contracting the virus, but it may reduce complications and prevent death in those who are infected.”
He said the correlation might also help to explain some of the mysteries surrounding COVID-19, including why children were less likely to die. Children did not have a fully developed acquired immune system, which was the immune system’s second line of defence and more likely to overreact.
Prof. Backman cautioned that people should not take excessive doses of vitamin D, which might come with negative side effects. He said the subject needed more research to know how vitamin D could be used most effectively to protect against COVID-19 complications.
MindBodyGreen reports a similar independent study that reached the same conclusions about vitamin D and COVID-19 mortality rates.
It added that vitamin D deficiency was extremely common in older people, with up to 75 per cent of residents in aged care or assisted living facilities aged 70-plus having a deficiency.
Do you have regular general check-ups with your doctor? Does he or she monitor such things as vitamin D?
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