Reduced Vitamin D Levels Associated with Increased COVID-19–Related Deaths

Lower levels of vitamin D are linked with a higher rate of deaths related to COVID-19, according to researchers from the Department of Respiratory Medicine at Princess Royal Hospital in Telford, United Kingdom. The findings of their study were presented at the American Thoracic Society 2021 International Conference.

“Vitamin D supports immunity and inflammation by inhibiting proinflammatory cytokine release from macrophages and up-regulating the expression of anti-microbial peptides exhibiting anti-viral activity,” the study authors noted. “Studies continue to investigate the therapeutic effects and establish the optimal serum levels of [inactive main circulating vitamin D] required to reduce the impact of respiratory tract infections whilst avoiding toxic hypercalcaemic high-dose ‘blind’ supplementation.” In this study, researchers analyzed clinical outcomes for 516 patients who were admitted with COVID-19 to a semi-rural hospital during the first four months of the pandemic in the UK, comparing those with reduced versus adequate vitamin D levels.

Historic and updated vitamin D levels were available for 163 patients (31.5%). Seventy-four patients (14.3%) were already on vitamin D supplements at the time of admission, and an additional 10 (1.9%) initiated supplementation during the admission.

Among the 163 patients, more than half (n=86; 52.7%) had reduced vitamin D levels (defined as either “deficient” or “insufficient”). These patients had higher rates of COVID-19–related mortality. Twenty-nine of these patients (33.7%) died during the admission, compared with 13 of the 74 patients (17.6%) with adequate vitamin D levels.

These data highlight that “less than a third of admitted COVID-19 patients have recorded vitamin D levels and, of these, more than half have reduced levels,” the authors concluded. “Very few [patients] get tested during the acute admission or get started on supplements, [despite] a statistical difference highlighting adverse outcome for those with reduced vitamin D levels.”