Laboratory evidence provides a biological rationale for the benefits of vitamin D in COVID-19, and vitamin D supplementation is associated with reduced risk of respiratory infections. Most of the clinical studies of vitamin D in COVID-19 have been observational, and the most serious problem with observational study design is that of confounding. Observational studies typically assess the relationship of 25(OH)D values with COVID-19 outcomes. Many conditions associated with low vitamin D status are also associated with worse COVID-19 outcomes. Randomized controlled trials (RCTs) overcome the problem of confounding, typically comparing outcomes between groups receiving vitamin D supplementation or placebo. However, any benefit of vitamin D in COVID-19 may be related to the dose, duration, daily vs. bolus administration, interaction with other treatments, and timing of administration prior to or during the illness. Serum 25(OH)D values >50 nmol/L have been associated with reduced infection rates, severity of COVID-19, and mortality in observational studies. Few RCTs of vitamin D supplementation have been completed, and they have shown no benefit of vitamin D in hospitalized patients. Vitamin D may benefit those with mild or asymptomatic COVID-19, and those with greater 25(OH)D values may have lower risk of acquiring infection. Because those at greatest risk of COVID-19 are also at greatest risk of vitamin D deficiency, it is reasonable to recommend vitamin D supplementation 15–20 mcg (600–800 IU) daily for the general population during the COVID-19 pandemic. Vitamin D doses greater than 100 mcg (4000 IU) daily should not be used without monitoring serum 25(OH)D and calcium.
【저자키워드】 Epidemiology, cholecalciferol, 25-hydroxyvitamin D, nutrition, Infection, clinical trials, Study design, 【초록키워드】 COVID-19, respiratory infections, Mortality, Vitamin D, COVID-19 pandemic, risk, outcome, hospitalized patients, observational studies, RCT, observational study, outcomes, serum, severity of COVID-19, Controlled trial, Mild, Placebo, General population, group, RCTs, Vitamin D status, clinical study, Evidence, Interaction, administration, dose, Asymptomatic COVID-19, deficiency, Vitamin D supplementation, reduced risk, infection rates, lower risk, other treatments, MOST, risk of COVID-19, benefit, greater, shown, receiving, reduced, provide, condition, overcome, with COVID-19, 【제목키워드】 COVID-19, Vitamin D, clinical, Evaluating,