A study conducted by researchers from Bar Ilan University and the Galilee Medical Center showed that among hospitalized COVID-19 patients, pre-infection deficiency of vitamin D was associated with increased disease severity and mortality.
The study, published Thursday by Plos One (Pre-infection 25-hydroxyvitamin D3 levels and association with severity of COVID-19 illness), examined the records of individuals admitted between April 7, 2020, and February 4, 2021, to the Galilee Medical Center (GMC) in Nahariya, Israel, with positive PCR tests for COVID-19, and discovered that a lower vitamin D status was more common in patients with severe or critical disease than in individuals with mild or moderate disease.
Patients with vitamin D deficiency (less than 20 ng/mL) were 14 times more likely to have a severe or critical case of COVID than those with more than 40 ng/mL.
Vitamin D is most often recognized for its role in bone health, but low levels of the supplement have been associated with a range of autoimmune, cardiovascular, and infectious diseases. Early on in the pandemic health officials began to encourage people to take vitamin D, as it plays a role in promoting immune response and could protect against COVID-19.
The study is among the first to analyze vitamin D levels before infection, which facilitates a more accurate assessment than during hospitalization, when levels may be lower secondary to the viral illness. The findings reported today build upon results initially published on MedRxiv.
Strikingly, mortality among patients with sufficient vitamin D levels was 2.3%, in contrast to 25.6% in the vitamin D deficient group.
The study adjusted for age, gender, season (summer/winter), chronic diseases, and found similar results across the board highlighting that low vitamin D level contributes significantly to disease severity and mortality.
“Our results suggest that it is advisable to maintain normal levels of vitamin D. This will be beneficial to those who contract the virus,” says Dr. Amiel Dror, of the Galilee Medical Center and Azrieli Faculty of Medicine of Bar-Ilan University, who led the study. “There is a clear consensus for vitamin D supplementation on a regular basis as advised by local health authorities as well as global health organizations.”
Dr. Amir Bashkin, an endocrinologist who participated in the current study, adds that “This is especially true for the COVID-19 pandemic when adequate vitamin D has an added benefit for the proper immune response to respiratory illness.”
“This study contributes to a continually evolving body of evidence suggesting that a patient’s history of vitamin D deficiency is a predictive risk factor associated with poorer COVID-19 clinical disease course and mortality,” said study co-author Prof. Michael Edelstein, of the Azrieli Faculty of Medicine of Bar-Ilan University. “It is still unclear why certain individuals suffer severe consequences of COVID-19 infection while others don’t. Our finding adds a new dimension to solving this puzzle.”
According to Dr. Dror, the coronavirus doesn’t change fundamentally between variants to the point where vitamin D would be ineffective against the infection, and although the study was conducted before the spread of the Omicron variant, a sufficient presence of Vitamin D in one’s system would boost their immune systems to deal with any viral attack on the respiratory system.
In conclusion, the study authors said: “From the early stages of the COVID-19 pandemic, establishing vitamin D deficiency as a risk factor was the aim of many investigators. It was subject to much debate in the general public and multiple medical journals. Our study contributes to a continually evolving body of evidence that suggests a patient’s history of vitamin D deficiency is a predictive risk factor associated with poorer COVID-19 clinical disease course and mortality. The use of historical results obtained before the COVID-19 pandemic as part of a public health survey enabled us to suggest vitamin D deficiency contributes to the causal pathway of COVID-19 mortality risk and disease severity. Our study warrants further studies investigating if and when vitamin D supplementation among vitamin D deficient individuals in the community impacts the outcome of an eventual COVID-19 episode.”
