Is there an association between vitamin D levels and COVID-19 mortality? Original paper

Low vitamin D levels have recently been associated with greater COVID-19 severity and mortality.

This retrospective cohort study enrolled 144 COVID-19 patients hospitalized in two different hospitals (one in Boston, the other in New York) between February 1 and May 15, 2020. It looked for associations between serum levels of 25(OH)D (25-hydroxyvitamin D) and two outcomes: mortality and invasive mechanical ventilation.

Higher 25(OH)D was associated with lower mortality: ≥30 ng/mL (≥75 nmol/L) with 9.2% mortality; <30 ng/mL with 25.3% mortality.

This association persisted after adjustment for the following covariates: gender, smoking status, COPD, diabetes, hypertension, malignant disease, coronary artery disease, heart failure, CRP levels, use of azithromycin, use of corticosteroids, and hospital .

Higher 25(OH)D was nonsignificantly associated with less need for mechanical ventilation. This association became statistically significant after adjustment for the following covariates: gender, smoking status, diabetes, hypertension, coronary artery disease, heart failure, CRP levels, use of azithromycin, use of any other antibiotics, and use of corticosteroids.

In the final models for mechanical ventilation, the authors adjusted for CRP levels, which is really a marker for disease severity, and the decision to mechanically ventilate would have been at least partially based on CRP levels. However, this doesn’t change the findings in any notable way.

The role of vitamin D in COVID-19 has been reviewed in previous issues of Examine Personalized:

A meta-analysis associated vitamin D levels under 30 ng/mL with a 43% increase in odds of COVID-19 infection.

A narrative review reported that vitamin D supplementation may benefit patients with COVID-19 by reducing the macrophage-driven hyperinflammatory response in the lungs.

A systematic review and meta-analysis found that, while vitamin D deficiency was not associated with the risk of COVID-19 infection, people who had COVID-19 had lower vitamin D levels than those who did not have COVID-19.

A review reported a notable correlation between lower vitamin D levels and both COVID-19 infection rate and poor COVID-19 outcomes. It hypothesized that vitamin D might reduce the risk of COVID-19 infection and death by improving innate immunity, maintaining cell junctions, modifying gene expression, and acting as an antimicrobial.

A retrospective cohort study found a strong, inverse correlation between vitamin D levels and COVID-19 infection rate.

A cohort study found that COVID-19 patients taking a supplement containing 150 mg of magnesium, 500 μg of B₁₂, and 25 μg (1,000 IU) of D₃ were less likely to require supplemental oxygen or ICU support than a control group.

A pilot randomized controlled trial found that ICU admission was needed by 50% of the COVID-19 patients not taking vitamin D, but by only 2% of those taking vitamin D.

One systematic review found that COVID-19 patients with a poor prognosis had lower levels of vitamin D than those with a good prognosis.

A retrospective cohort study found that people with vitamin D deficiency were more likely to die from COVID-19.