TORONTO -- More than 80 per cent of COVID-19 patients at a hospital in Spain had a vitamin D deficiency, .
Researchers at the University Hospital Marques de Valdecilla in Santander, Spain looked at the vitamin D levels of 216 patients admitted to hospital for coronavirus treatment between March 10 and March 31.
For the study, the 216 hospitalized patients鈥� vitamin D levels were compared to those of a control group of 197 people of similar age and sex from a population-based cohort in the same geographical area.
Of the 216 hospitalized patients, 19 who had been taking oral vitamin D supplements for more than three months before their admissions were analyzed as a separate group.
The researchers found that 82 per cent of the hospitalized COVID-19 patients (who were not taking supplements) were vitamin D deficient, while 47 per cent of the control group had the same deficiency.
The study also noted that vitamin D levels were 鈥渆specially lower鈥� in men with COVID-19 compared to women.
Dr. Jose Hernandez, a co-author of the study and an associate professor of neurophysiology at the University of Cantabria in Spain, said there are many factors that could explain why men with COVID-19 had lower vitamin D levels than women, including lifestyle or dietary habits and different comorbidities.
The study鈥檚 authors were particularly interested in studying vitamin D because they said there鈥檚 evidence to suggest it plays a role in COVID-19 infection. Vitamin D is a hormone produced by the kidneys, which controls blood calcium concentration and affects the function of the immune system.
Vitamin D deficiency has also been linked to health concerns including heart disease, diabetes, cancer, and multiple sclerosis.
According to the study, there is also 鈥渃ompelling evidence鈥� for an epidemiological association between low levels of vitamin D and infections such as influenza, HIV, and the hepatitis C virus.
鈥淭here are numerous pieces of evidence in the literature that support the beneficial effect of vitamin D on the immune system, especially regarding protection against infections, including viral infections,鈥� Hernandez said in an email to CTVNews.ca on Sunday.
While the researchers reported a higher prevalence of vitamin D deficiency in hospitalized COVID-19 patients compared to the control group, they did not find an association between vitamin D levels and the severity of the disease, such as the need for ICU admission, mechanical ventilation, or even death.
And, although they didn鈥檛 establish an association between vitamin D deficiency and the severity of COVID-19, the study鈥檚 authors noted that the group of hospitalized patients who had been taking oral supplements prior to admission had slightly more favourable outcomes than those who didn鈥檛 take supplements before they were admitted to hospital, including lower ferritin levels, a decreased need for the immunosuppressive drug tocilizumab, and lower ICU admissions.
The study found that patients with a vitamin D deficiency also had raised serum levels of inflammatory markers, such as ferritin and D-dimer.
鈥淭he most severe forms of COVID-19 are characterized by a hyperinflammatory state, the so-called 鈥榗ytokine storm,鈥� that occurs over the first week of symptoms鈥� onset, and led to acute respiratory distress syndrome and other organ complications causing increased mortality,鈥� Hernandez explained.
鈥淲e found that COVID-19 patients with lower serum vitamin D levels had raised serum ferritin and D-dimer levels, which are markers of this hyperinflammatory response.鈥�
In addition to not establishing a relationship between low levels of vitamin D and the severity of COVID-19, including mortality, the study鈥檚 authors also acknowledged their research doesn鈥檛 show that vitamin D deficiency is a risk factor for contracting the disease.
鈥淲e must wait for the results of the ongoing large and properly designed studies to determine whether vitamin D can prevent SARS-COV-2 infection, or reduce its severity,鈥� Hernandez said.
Given the safety and low cost of vitamin D treatments, Hernandez said it would be reasonable to treat those who are most at risk of vitamin D deficiency, such as seniors and those with comorbidities, and who also happen to be the most at risk for developing severe outcomes from COVID-19.
in the Endocrine Society鈥檚 鈥淛ournal of Clinical Endocrinology & Metabolism鈥� on Tuesday.
