Chicago, IL—Vitamin D deficiency may raise the risk of getting COVID-19, according to aretrospective studyperformed by researchers at the University of Chicago.

"Vitamin D is important to the function of the immune system and vitamin D supplements have previously been shown to lower the risk of viral respiratory tract infections," said David Meltzer, MD, PhD, Chief of Hospital Medicine at UChicago Medicine and lead author of the study, in a press release. "Our statistical analysis suggests this may be true for the COVID-19 infection."

The researchers looked at 489 UChicago Medicine patients whose vitamin D level had been measured within a year before being tested for COVID-19. Patients who had untreated vitamin D deficiency were almost twice as likely to test positive for the COVID-19 coronavirus compared to patients who had sufficient levels of vitamin D.
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The press release notes that half of Americans are deficient in vitamin D, with much higher rates seen in African Americans, Hispanics, and those who live in areas where it is difficult to get enough sun exposure in winter.

Meltzer and his team emphasized the importance of experimental studies to determine whether vitamin D supplementation could reduce risk and severity of COVID-19. They have initiated several clinical trials, at UChicago Medicine and with local partners.

"Understanding whether treating Vitamin D deficiency changes COVID-19 risk could be of great importance locally, nationally and globally," Meltzer said in the press release. "Vitamin D is inexpensive, generally very safe to take, and can be widely scaled."