A study funded in part by the National Center for Advancing Translational Sciences (NCATS) suggests that Black individuals with vitamin D levels on the low end of what is typically considered sufficient have a higher risk of COVID-19 than those with higher levels of vitamin D.
Vitamin D plays an important role in immune system functioning, and research points to a link between vitamin D supplementation and fewer viral respiratory infections. But it’s not clear if lower levels of vitamin D are linked to a greater risk of COVID-19, particularly among people in at-risk populations. If lower levels of vitamin D are tied to greater COVID-19 risk, then vitamin D supplementation might offer an easy, low-cost therapeutic option to help prevent COVID-19.
In a recent study in JAMA Network Open, researchers at the University of Chicago assessed whether a person’s risk of testing positive for COVID-19 was associated with their levels of vitamin D within the year prior to the test. The scientists, who were part of the NCATS-funded Clinical and Translational Science Awards (CTSA) Program, also examined vitamin D levels and COVID-19 risk separately among White people and among Black people.
Among all 4,638 people tested for COVID-19, those with the lowest levels of vitamin D were 53% more likely to test positive than those with the highest levels. Assessed separately, White individuals with lower vitamin D levels weren’t at significantly greater risk of COVID-19. However, Black individuals were at significantly greater risk of testing positive for COVID-19. Those with the lowest levels of vitamin D were 164% more likely to test positive than those with the highest levels.
Even among the Black individuals with vitamin D levels above 30 ng/ml - the level traditionally considered sufficient - the risk of having positive COVID-19 results was 2.64-fold greater with a vitamin D level of 30 to 39.9 ng/mL than a level of 40 ng/mL or greater. This difference was not seen in White individuals.
The researchers are now conducting a randomized, controlled trial to see what effect low, medium and high doses of vitamin D supplementation have on COVID-19 risk.