Try upping vitamin D levels to 40 ng/mL or greater to prevent COVID?
In their discussion, the authors noted that significant association of vitamin D levels with COVID-19 risk in Blacks but not in Whites, “could reflect their higher COVID-19 risk, to which socioeconomic factors and structural inequities clearly contribute.
“Biological susceptibility to vitamin D deficiency may also be less frequent in White than Black individuals, since lighter skin increases vitamin D production in response to sunlight, and vitamin D binding proteins may vary by race and affect vitamin D bioavailability.”
Given less than 10% of U.S. adults have a vitamin D level greater than 40 ng/mL, the study findings increase the urgency to consider whether increased sun exposure or supplementation could reduce COVID-19 risk, according to the authors.
“When increased sun exposure is impractical, achieving vitamin D levels of 40 ng/mL or greater typically requires greater supplementation than currently recommended for most individuals of 600-800 IU/d vitamin D3,” they added.
However, Dr. Meltzer also acknowledged that “this is an observational study. We can see that there’s an association between vitamin D levels and likelihood of a COVID-19 diagnosis, but we don’t know exactly why that is, or whether these results are due to the vitamin D directly or other related biological factors.”
All in all, the authors suggested that randomized clinical trials are needed to understand if vitamin D can reduce COVID-19 risk, and as such they should include doses of supplements likely to increase vitamin D to at least 40 ng/mL, and perhaps even higher, although they pointed out that the latter must be achieved safely.
“Studies should also consider the role of vitamin D testing, loading doses, dose adjustments for individuals who are obese or overweight, risks for hypercalcemia, and strategies to monitor for and mitigate hypercalcemia, and that non-White populations, such as Black individuals, may have greater needs for supplementation,” they outlined.
They are now recruiting participants for two separate clinical trials testing the efficacy of vitamin D supplements for preventing COVID-19.
The authors disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.