WEDNESDAY, July 28, 2021 (HealthDay News) -- Unlocking a clue to why Black women might be more susceptible to COVID-19, a new study shows that low levels of vitamin D may increase their risk of infection.
That doesn't mean that people should rely on vitamin D supplements to protect themselves against COVID-19, however, because vaccines are the only proven protection against the disease.
For the study, researchers assessed vitamin D levels among women who had been tested for COVID-19. The investigators analyzed data from the Black Women's Health Study that was launched in 1995 and enrolled 59,000 Black women aged 21 to 69.
The researchers concluded that Black women with deficient levels of vitamin D had a 69% higher risk of COVID-19 infection than those with sufficient vitamin D levels.
"Nearly one out of four people have vitamin D blood levels that are too low or inadequate for bone and overall health," said study lead author Yvette Cozier, an associate professor of epidemiology at Boston University School of Public Health and an investigator on the Black Women's Health Study at the university's Slone Epidemiology Center. "Our study provides another reason why adequate levels of vitamin D are important — the possibility of lowering risk of COVID-19 infection."
This association was strongest among obese women, which is an important finding given the higher rate of obesity among Black women compared to other women, according to the authors of the study published online July 27 in the journal PLOS ONE.
The team noted that some previous studies have found links between vitamin D levels and COVID-19 risk, but they mainly included white people and didn't provide risk estimates based on either race or body fat.
Vitamin D deficiency is common among Black women, so these findings may help explain in part why they have an increased risk of COVID-19, the researchers said in a university news release.
The study also found that a number of major factors associated with COVID-19 risk — number of people in a household, years of education and neighborhood wealth — didn't account for the association between vitamin D levels and COVID-19 risk.
Vitamin D is obtained from supplements, from oily fish, red meat, liver and fortified foods. The body also produces it in response to exposure of skin to sunlight, leading to its nickname — the "sunshine" vitamin.
Clinical trials are now being conducted to determine whether vitamin D helps reduce COVID-19 risk or ease symptoms in people who have COVID-19.
Vitamin D deficiency and obesity are known to be linked with a risk of chronic diseases like osteoporosis, cancer, and heart disease.
The Harvard School of Public Health has more on vitamin D and health.
SOURCE: Boston University, news release, July 27, 2021