, in a retrospective, case-matched study.
The lower levels of vitamin D in patients with long COVID were most notable in those with brain fog.
These findings, by Luigi di Filippo, MD, and colleagues, were recently presented at the European Congress of Endocrinology and published in the Journal of Clinical Endocrinology & Metabolism.
“Our data suggest that vitamin D levels should be evaluated in COVID-19 patients after hospital discharge,” wrote the researchers, from San Raffaele Hospital, Milan.
“The role of vitamin D supplementation as a preventive strategy of COVID-19 sequelae should be tested in randomized controlled trials,” they urged.
The researchers also stressed that this was a controlled study in a homogeneous population, it included multiple signs and symptoms of long COVID, and it had a longer follow-up than most previous studies (6 vs. 3 months).
“The highly controlled nature of our study helps us better understand the role of vitamin D deficiency in long COVID and establish that there is likely a link between vitamin D deficiency and long COVID,” senior author Andrea Giustina, MD, said in a press release from the ECE.
“Our study shows that COVID-19 patients with low vitamin D levels are more likely to develop long COVID, but it is not yet known whether vitamin D supplements could improve the symptoms or reduce this risk altogether,” he cautioned.
“If confirmed in large, interventional, randomized controlled trials, [our data suggest] that vitamin D supplementation could represent a possible preventive strategy in reducing the burden of COVID-19 sequelae,” Dr. Giustina and colleagues wrote.
Reasonable to test vitamin D levels, consider supplementation
Invited to comment, Amiel Dror, MD, PhD, who led a related study that showed that people with a vitamin D deficiency were more likely to have severe COVID-19, agreed.
“The novelty and significance of this [new] study lie in the fact that it expands on our current understanding of the interplay between vitamin D and COVID-19, taking it beyond the acute phase of the disease,” said Dr. Dror, from Bar-Ilan University, Safed, Israel.
“It’s striking to see how vitamin D levels continue to influence patients’ health even after recovery from the initial infection,” he noted.
“The findings certainly add weight to the argument for conducting a randomized control trial [RCT],” he continued, which “would enable us to conclusively determine whether vitamin D supplementation can effectively reduce the risk or severity of long COVID.”
“In the interim,” Dr. Dror said, “given the safety profile of vitamin D and its broad health benefits, it could be reasonable to test for vitamin D levels in patients admitted with COVID-19. If levels are found to be low, supplementation could be considered.”
“However, it’s important to note that this should be done under medical supervision,” he cautioned, “and further studies are needed to establish the optimal timing and dosage of supplementation.”
“I anticipate that we’ll see more RCTs [of this] in the future,” he speculated.