Led by David Meltzer, MD, PhD, Chief of Hospital Medicine at UChicago Medicine, the research team found that patients who had vitamin D deficiency (less than 20ng/ml) that was not treated were almost twice as likely to test positive for the COVID-19 coronavirus compared to patients who had sufficient levels of the vitamin.
“Vitamin D is important to the function of the immune system and vitamin D supplements have previously been shown to lower the risk of viral respiratory tract infections,” said Dr Meltzer. “Our statistical analysis suggests this may be true for the COVID-19 infection.”
A wave of scientific publications has suggested that vitamin D3 supplementation could be a potentially promising and safe approach to reduce risk of COVID-19 infections and deaths. Meta-analyses of randomized clinical trials (RCTs) have shown that vitamin D3 supplementation reduces the risk of acute respiratory tract infections.
And with half of Americans deficient in Vitamin D, understanding whether treating Vitamin D deficiency changes COVID-19 risk could be of great importance locally, nationally and globally, said Dr Meltzer.
“Vitamin D is inexpensive, generally very safe to take, and can be widely scaled,” he said.
The sunshine vitamin
Vitamin D refers to two biologically inactive precursors - D3, also known as cholecalciferol, and D2, also known as ergocalciferol. Both D3 and D2 precursors are transformed in the liver and kidneys into 25- hydroxyvitamin D (25(OH)D), the non-active 'storage' form, and the active form 1,25-dihydroxyvitamin D (1,25(OH)2D).
While our bodies do manufacture vitamin D on exposure to sunshine, the levels in some northern countries are so weak during the winter months that our body makes no vitamin D at all, meaning that dietary supplements and fortified foods are seen by many as the best way to boost intakes of vitamin D.
Dr Meltzer and his co-workers analyzed data from 489 UChicago Medicine patients whose vitamin D level was measured within a year before being tested for COVID-19.
Data published in JAMA Network Open indicated that the relative risk of testing positive for COVID-19 was 1.77 times greater for people with vitamin D deficiency compared with people with sufficient levels. This result was statistically significant, stated the researchers.
“The findings of this study suggest a role of vitamin D status, based on deficiency of levels and treatment, in risk of COVID-19 infection,” wrote the researchers.
“Randomized clinical trials of interventions to reduce vitamin D deficiency are needed to determine if those interventions could reduce COVID-19 incidence, including both broad population interventions and interventions among groups at increased risk of vitamin D deficiency and/or COVID-19.”
Also in the literature
Recently, a team of researchers from Germany Cancer Research Center analyzed data from almost 10,000 people and found that vitamin D insufficiency and deficiency (25-hydroxyvitamin D blood levels of 30–50 and <30 nmol/L, respectively) were found to be common (44% and 15%, respectively), and compared to those with sufficient status, participants with vitamin D insufficiency and deficiency had strongly increased respiratory mortality.
In addition, researchers from Trinity College in Dublin, Ireland stated earlier this year that vitamin D deficiency is suggested to play an important role in the severity of COVID-19 infections.
Writing in Alimentary Pharmacology and Therapeutics, the Trinity College scientists stated: “… the evidence supporting a protective effect of vitamin D against severe COVID‐19 disease is very suggestive, a substantial proportion of the population in the Northern Hemisphere will currently be vitamin D deficient, and supplements, for example, 1000 international units (25 micrograms) per day are very safe.
“It is time for governments to strengthen recommendations for vitamin D intake and supplementation, particularly when under lock‐down.”
Source: JAMA Network Open
2020;3(9):e2019722. doi: 10.1001/jamanetworkopen.2020.19722
“Association of Vitamin D Status and Other Clinical Characteristics With COVID-19 Test Results”
Authors: D.O. Meltzer, et al.