Higher levels of vitamin D than traditionally thought could be enough to help prevent COVID-19 infection – especially in Black patients, a new single-center, retrospective study looks on the role of vitamin D in preventing infection.
The study, recently published in JAMA Open Network, noting that experts’ views on “adequate” levels of vitamin D are changing, some define this as 30 ng / mL, while others cite 40 ng / mL or greater.
In their discussion, the authors also note that their results show: “The risk of positive COVID-19 test results is significantly reduced by an increase in vitamin D level of 30 ng / mL or more when measured as a continuous variable. “
“These new results tell us that vitamin D levels above those normally considered appropriate are associated with a lower risk for testing for COVID-19, at least. in blacks, “lead author David Meltzer, MD, head of hospital medicine at the University of Chicago Medicine in Illinois, said in a press release from his institute.
“These findings suggest randomized clinical trials to determine whether increasing vitamin D levels to more than 30 to 40 ng / mL affects the risk of COVID-19, particularly in black people, “he and his coauthors say.
Vit D at the time of the test is most strongly associated with COVID risk
An earlier study by the same researchers found that vitamin D deficiency (less than 20 ng / ml) may increase the risk of testing positive for COVID-19 in people of different races, as reported by Medscape.
Data for this latest study were extracted from electronic health records for 4638 individuals at the University of Chicago University of Medicine and were used to examine whether the appearance of a positive COVID-19 test was related to a person’s latest vitamin D level. (within the previous year)), and whether racism had any effect on this outcome.
The average age was 52.8 years; 69% were women; 49% were black; 43% white; and 8% were of other races / ethnicities.
27% of all people were deficient in vitamin D (less than 20 ng / mL), 27% did not have sufficient levels (20 to less than 30 ng / mL), had adequate levels 22% (30 to less than 40 ng / mL), while the remaining 24% had levels of 40 ng / mL or greater.
In total, 333 (7%) people tested positive for COVID-19, including 102 (5%) whites and 211 (9%) Blacks. And 36% of black people who tested positive for COVID-19 were classified as vitamin D deficient, compared to 16% of white people.
A positive test result for COVID-19 was not significantly associated with vitamin D levels in white people but it was in black people.
Thus in black people, compared with ≥40 ng / mL levels, vitamin D levels of 30 to <40 ng / mL were associated with a frequency ratio (IRR) ratio of 2.64 for COVID-19 sensitivity (P. = 0.01). For levels 20 to <30 ng / mL, the IRR was 1.69 (P. = 0.21); and for <20 ng / mL the IRR was 2.55 (P. = .009).
The researchers also found that the risk from positive test results increased with lower vitamin D levels when those levels were lower just before the COVID-19 positive test, providing a “supportive” loan. [to] the idea that vitamin D level at the time of the test is strongly linked to the risk of COVID-19, ”they write.
Try Upping Vitamin D Levels to 40 ng / mL or more to prevent COVID?
In their discussion, the authors note that vitamin D levels may be significantly associated with COVID-19 risk in Blacks but not in white people, “revealing a higher COVID-19 risk , to which socio-economic factors and structural inequality clearly contribute. “
“Biological susceptibility to vitamin D deficiency may also be less common in whites than blacks, as lighter skin increases vitamin D production in response to sunlight, and vitamin D binding proteins can alter according to race and affect the bioavailability of vitamin D. “
With less than 10% of U.S. adults with a vitamin D level greater than 40 ng / mL, the study’s findings increase the urgency to consider whether increased sun exposure or sun exposure -is to reduce the risk of COVID-19, according to the authors.
“‘ When increased sun exposure is impractical, achieving vitamin D levels of 40 ng / mL or more usually requires more than currently recommended for most people individually 600-800 IU / d vitamin D3, “they add.
However, Meltzer also admits, “This is a speculative study. We see a link between vitamin D levels and the likelihood of a COVID-19 diagnosis, but we don’t know for sure why that is, or whether these results are due directly to vitamin D or other related biological factors. “
Overall, the authors suggest that randomized clinical trials are needed to understand whether vitamin D can reduce the risk of COVID-19, and therefore should be ingested. of medications that tend to increase vitamin D to at least 40 ng / mL, and possibly even higher, although they indicate that the latter must be safely achieved.
“Studies should also consider the role of vitamin D testing, loading doses, dose changes for obese or obese individuals, risks for hypercalcemia, and strategies to monitor for and alleviate hypercalcemia, and that numbers non – whites, such as blacks, may have greater needs for development, “they explain.
They are now recruiting participants for two separate clinical trials testing the efficacy of vitamin D products for the inhibition of COVID-19.
The authors did not disclose any material financial relationships.
JAMA Netw Open. 2021; 4: e214117. Full text
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