Researchers say people who are deficient in vitamin D are more likely to have severe or fatal cases of Covid-19. In a retrospective study published in the journal Plos One, scientists from Galilee Medical Center and Bar Ilan University in Israel examined the records of more than 1,176 patients treated between April 7, 2020 and February 4, 2021.
The note looked for vitamin D levels seen two weeks to two years before infection. Individuals are categorized according to vitamin D levels (characterized as deficient, insufficient, adequate, and normal high) and the severity of Covid-19 disease, which is determined using multivariable regression analysis.
More than 250 patients had record levels of vitamin D before Covid-19 infection, with the team finding that patients who were vitamin D deficient were 14 times more likely to have severe or critical cases of Covid-19. The mortality rate among patients with adequate vitamin D levels was 2.3 percent compared to 25.6 percent in the deficient group.
"Lower vitamin D status is more common in patients with severe or critical illness than in individuals with mild or moderate illness," the study concluded.
If adjusted for age, gender, season, and history of chronic disease, those differences remained true. According to Bar Ilan University, the study was one of the first to analyze vitamin D levels before infection, and the infection builds on results originally published in MedRxiv.
"Our results suggest that it is advisable to maintain normal vitamin D levels. This will benefit those who contract the virus," said Amiel Dror, lead author of the study from Galilee Medical Center and Azrieli Bar-Ilan University School of Medicine.
There is a clear consensus for regular vitamin D supplementation as suggested by local health authorities, as well as global health organizations. This study contributes to growing evidence suggesting that a patient's history of vitamin D deficiency is a predictive risk factor associated with the course of clinical illness and Covid-19 death.
Michael Edelstein, co-author of the study from the Azrieli School of Medicine at Bar-Ilan University, said it remains unclear why certain individuals suffer severe consequences from Covid-19 infection, while others do not.
The study is based on studies conducted before the coronavirus vaccine was widely available. Doctors stress that vitamin supplements are not a substitute for vaccines, but a way to help immunity levels. Dror said while the study was also conducted before the surge in omicron variants, the coronavirus did not change fundamentally enough among variants to negate the effectiveness of vitamin D.
Health officials in some countries have recommended vitamin D supplements during pandemics. According to the Cleveland Clinic, vitamin D helps keep bones strong, absorb calcium, and work with the parathyroid glands.
Symptoms of deficiency include fatigue, bone loss, mood swings, muscle cramps, and bone and joint pain. Negative health effects of vitamin D deficiency, including heart disease, high blood pressure, diabetes, immune system disorders, multiple sclerosis, falls in the elderly, and some cancers.