A low level of vitamin D in blood plasma appears to be an independent risk factor for Covid-19 infection and hospitalization, say scientists from Israeli HMO Leumit Health Services and the Azrieli Faculty of Medicine of Bar-Ilan University.
The researchers came to their conclusion using real-world data and an Israeli cohort of 782 Covid-19 positive patients and 7,025 Covid-19 negative patients.
“The main finding of our study was the significant association of low plasma vitamin D level with the likelihood of Covid-19 infection among patients who were tested for Covid-19, even after adjustment for age, gender, socio-economic status and chronic, mental and physical disorders,” said Dr. Eugene Merzon, head of Leumit’s Department of Managed Care.
“Furthermore, low vitamin D level was associated with the risk of hospitalization due to Covid-19 infection, although this association wasn’t significant after adjustment for other factors,” he added.
The scientists’ research follows a few worldwide studies that have shown the pronounced impact of vitamin D metabolites on the immune system response and on the development of Covid-19 infection by the novel SARS CoV-2 coronavirus.
“Our finding is in agreement with the results of previous studies in the field. Reduced risk of acute respiratory tract infection following vitamin D supplementation has been reported,” said Dr. Ilan Green, head of Leumit’s Research Institute.
As for the amount of vitamin D required, Merzon says it should be “personalized and take into account patients’ age, gender, race and ethnicity, nutritional status and health condition.”
Their report on the study was published in The FEBS Journal and is expected to make a wide impact because of the study’s size and population-based structure.
Dr. Milana Frenkel-Morgenstern, leader of the Azrieli Faculty of Medicine research group, added that the analysis showed people who were Covid-19 positive were older than non-infected people.
“Interestingly, the two-peak distributions for age groups were demonstrated to confer increased risk for Covid-19: around ages 25 and 50 years old,” she said.
“The first peak may be explained by high social gathering habits at the young age. The peak at age 50 years may be explained by continued social habits, in conjunction with various chronic diseases.”
Leumit Chief Medical Officer Dr. Shlomo Vinker said he was surprised to discover that “chronic medical conditions, like dementia, cardiovascular disease and chronic lung disease that were considered to be very risky in previous studies, were not found as increasing the rate of infection in our study.”
However, he added, “this finding is highly biased by the severe social contacts restrictions that were imposed on all the population during the Covid-19 outbreak. Therefore, we assume that following the Israeli Ministry of Health instructions, patients with chronic medical conditions significantly reduced their social contacts. This might indeed minimize the risk of Covid-19 infection in that group of patients.”
Now this joint Israeli research team is planning to evaluate factors associated with Covid-19 mortality in Israel.
“We are willing to find associations to the Covid-19 clinical outcomes — for example, pre-infection glycemic control of Covid-19 patients — to make the assessment of mortality risk due to Covid-19 infection in Israel,” said Merzon.