A recent study published in the Journal of Clinical Endocrinology & Metabolism has shown that patients with long COVID have lower levels of vitamin D than those who have recovered from COVID-19. The study, conducted by Luigi di Filippo, MD, and colleagues, suggests that taking vitamin D supplements may help prevent or ease the debilitating condition. The researchers from San Raffaele Hospital in Milan, Italy, highlighted the strength of the study, which included patients with multiple symptoms of long COVID and had a longer follow-up than most previous studies.
However, while the study establishes a likely link between vitamin D deficiency and long COVID, it is not yet known whether vitamin D supplements could improve symptoms or reduce the risk altogether. Amiel Dror, MD, PhD, who led a related study, agreed that further studies are needed to establish the optimal timing and dosage of supplementation.
Low levels of vitamin D have previously been associated with increased likelihood of needing mechanical ventilation and worse survival in patients hospitalized with COVID. The researchers in this study analyzed data from adults age 18 and older who had been hospitalized with a confirmed COVID diagnosis and then discharged during the first pandemic wave from March to May 2020, and seen 6 months later at a follow-up clinic. Patients were excluded if they had been admitted to the intensive care unit during their hospitalization or if they had missing medical data or blood samples available to determine vitamin D levels.
The researchers identified 50 patients with long COVID at the 6-month follow-up and matched them with 50 patients without long COVID at that same point in time based on age, sex, other medical conditions, and need for noninvasive mechanical ventilation. The patients had an average age of 61 and 56% were men; 28% had been on a ventilator during their hospitalization for COVID.
In conclusion, the study suggests that vitamin D levels should be evaluated in COVID-19 patients after hospital discharge. While it is not yet known whether vitamin D supplements could improve symptoms or reduce the risk altogether, 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, under medical supervision.