Review the Research
Get summaries of key research on vitamin D and COVID-19
Association of vitamin D deficiency with COVID‐19 infection severity: Systematic review and meta‐analysis
Take Home Message
Vitamin D deficiency leads to poorer outcomes in individuals diagnosed with COVID–19.
Results
- Seventeen observational studies with 2756 patients were included in the analyses.
- Vitamin D deficiency was associated with significantly higher mortality higher rates of hospital admissions and longer hospital stays as compared to nonvitamin D deficient status.

Who
Eligible studies (1) included patients with laboratory‐confirmed COVID‐19 diagnosis (polymerase chain reaction [PCR]); (2) documented evaluation of total serum 25‐hydroxyvitamin D (25(OH)D) level within 3 months of COVID‐19 diagnosis; (3) availability of a comparison group: comparing vitamin D deficiency to nondeficiency (includes normal vitamin D status and insufficiency); and (4) reported outcomes of interest (mortality, hospital admission, length of hospital stay and intensive care unit [ICU] admission).
Things to Keep in Mind
- Not all studies controlled for confounding
- Most studies only included older individuals
- The cut offs to define vitamin D deficiency were not consistent across studies
Author’s Conclusions
“Vitamin D deficiency is associated with greater COVID‐19 infection severity as measured by rates of mortality, hospital admission and duration of hospital stay. Longitudinal interventional studies are warranted to determine if vitamin D supplementation can decrease COVID‐19 infection severity.”
Study Design
- Multiple databases from January 1st, 2019 to December 3rd, 2020 were searched for observational studies evaluating the association between vitamin D deficiency and severity of COVID‐19 infection.
- The main outcomes of interest were mortality, hospital admission, length of hospital stay and intensive care unit admission.
Reference
Wang Z, Joshi A, Leopold K, Jackson S, Christensen S, Nayfeh T, Mohammed K, Creo A, Tebben P, Kumar S. Association of vitamin D deficiency with COVID-19 infection severity: Systematic review and meta-analysis. Clin Endocrinol (Oxf). 2022 Mar;96(3):281-287. doi: 10.1111/cen.14540. Epub 2021 Jul 12. PMID: 34160843; PMCID: PMC8444883.