According to the study, 80% of 216 COVID-19 patients at the Hospital Universitario Marqués de Valdecilla had vitamin D deficiency. Out of that group of patients, men had lower vitamin D levels than women.
The study also found that patients with lower vitamin D levels had raised serum levels of inflammatory markers like ferritin, a blood protein that contains iron, and troponin, a complex of proteins found in skeletal and heart muscles. Troponin tests measure cardiac-specific troponin in the blood to identify heart injuries.
The findings also reveal that vitamin D-deficient COVID-19 patients had a “greater prevalence” of hypertension and cardiovascular disease and also ended up having longer hospital stays than patients not deficient in the vitamin.
However, the study did not find any link between vitamin D deficiency and COVID-19 severity.
"One approach is to identify and treat vitamin D deficiency, especially in high-risk individuals such as the elderly, patients with comorbidities and nursing home residents, who are the main target population for the COVID-19," study co-author José L. Hernández of the University of Cantabria in Santander, Spain, said in a news release.
"Vitamin D treatment should be recommended in COVID-19 patients with low levels of vitamin D circulating in the blood since this approach might have beneficial effects in both the musculoskeletal and the immune system,” Hernández added.
Several studies have pointed to the possible impact of vitamin D, which is produced by the body in response to sun exposure, in protecting against COVID-19.
A September retrospective study by the University of Chicago found a similar association after evaluating 489 patients whose vitamin D levels were measured a year before being tested for COVID-19.
The findings revealed that patients with untreated vitamin D deficiency were almost twice as likely to test positive for SARS-CoV-2, the virus that causes COVID-19, compared to patients who were not deficient in the vitamin.
Despite the promising studies, the US Centers for Disease Control and Prevention (CDC) has yet to make any declarative statement on the use of vitamin D for the prevention or treatment of COVID-19, stating that there is currently “insufficient data to recommend either for or against” the use of the vitamin.
“The role of vitamin D supplementation in the prevention or treatment of COVID-19 is not known. The rationale for using vitamin D is based largely on immunomodulatory effects that could potentially protect against COVID-19 infection or decrease the severity of illness. Ongoing observational studies are evaluating the role of vitamin D in preventing and treating COVID-19,” the CDC notes.
The CDC also warns on its website that “high levels of vitamin D may cause hypercalcemia and nephrocalcinosis.” Hypercalcemia occurs when calcium levels in the blood are above normal, weakening bones and causing kidney stones, while nephrocalcinosis refers to the deposition of calcium salts in the kidneys.