Higher levels of vitamin D than traditionally considered adequate can help prevent COVID-19 infection – especially in black patients – or lead to less serious outcomes, two new US studies have suggested.
Deficiency and infection
In the first, a large single-center observational study conducted late last week in JAMA Network open, Researchers from the University of Chicago, retrospectively reviewed the electronic health records of patients who underwent a vitamin D test in the year before testing on COVID-19 from March 3 to April 10, 2020. coronavirus testing is excluded.
Of the 4638 patients, the risk of a positive coronavirus test result in black patients was 2.64 times greater if they had a vitamin D level of 30 to 39.9 nanograms per milliliter (ng / ml) than if they had concentrations of at least 40 ng / ml. ml. And the chance of infection decreased by 5% for every 1 ng / ml increase in patients with a vitamin D level of at least 30 ng / ml. The concentration is generally considered adequate. Similar associations were not found for white patients.
Among the 4,638 patients, 27% were deficient in vitamin D (less than 20 ng / ml), 27% had inadequate levels (20 to less than 30 ng / ml), 22% had concentrations of 30 to less than 40 ng / ml and 24% had levels of more than 40 ng / ml. Black patients tended to have lower vitamin D levels than their white counterparts (36% versus 16% at 20 ng / ml).
Seven percent of all participants tested positive for COVID-19, including 5% of Whites and 9% of Black patients. In multivariate analysis that has temporarily controlled since vitamin D level was last measured, positive COVID-19 test results were significantly linked to vitamin D levels in black but not white patients.
Compared to patients with a concentration of at least 40 ng / ml, those with less than 20 ng / ml were 2.55 times more likely to be diagnosed as COVID-19, while those with 30 to greater than 40 ng / ml 2.64 times was more likely. Estimated coronavirus infection rates in black patients, stratified according to vitamin D level, were 9.72% for a concentration of 20 ng / ml, 6.47% at 20 to 30 ng / ml, 10.10% at 30 to less than 40 ng / ml and 3.82% at 40 ng / ml or higher.
The mean patient age was 52.8 years, 69% were women, 49% were black, 43% were white, and 8% were of a different race or ethnicity. Vitamin D levels are affected by exposure to sunlight and by diet or supplements.
Lead study author David Meltzer, MD, PhD, said in a press release from the University of Chicago Medical Center that the current vitamin D guidelines come primarily from studies on bone health. “But there is also evidence that vitamin D can improve immune function and reduce inflammation,” he said.
“Based on these results, we think that previous studies may have given doses that were too low to have a major impact on the immune system, even if it was adequate for bone health. It could be that different levels of vitamin D is sufficient for different functions. “
The researchers are now recruiting for two clinical trials to test whether daily supplementation of vitamin D can reduce the risk and severity of COVID-19, especially for black people. “Currently, the recommended nutritional requirement for vitamin D for adults is 600 to 800 international units (IUs) per day,” Meltzer said in the release. The National Academy of Medicine said that ingesting up to 4000 IU per day is safe for the vast majority of people, and the risk of hypercalcemia [excessively high calcium levels] rises to levels above 10,000 IU per day. “
Chances of mechanical ventilation, death
The second study, presented virtually at the Endocrine Society’s annual meeting late last week, involved 124 adults with low vitamin D, measured up to 90 days before hospitalization for COVID-19, to measure the results of those taking at least 1,000 units of the a press release from society weekly vitamin with those who do not.
Patients who have taken supplements of at least 1,000 vitamin D units per week have a slightly lower chance of needing mechanical ventilation or dying of their infections (33.3% vs. 37.5%), although the finding does not was not statistically significant. More than half of the patients who had to take supplements due to a deficiency were not.
Study co-author Corrine Levitus, DO, of Montefiore Health System and Albert Einstein College of Medicine, said in the release that despite the lack of a definite link between insufficient vitamin D and severe COVID-19, a lack of patients receive supplements to protect against weak coronavirus. outcomes as well as against osteoporosis. “We hope this research will encourage clinicians to discuss this supplement with their patients on a low vitamin D dose, as it may reduce the chances of people developing severe COVID-19,” she said.