Does vitamin D supplementation reduce COVID-19 severity?: a systematic review

Area of Science:

• * Nutritional Immunology
• * Infectious Disease Management

Background:

• * Existing evidence on vitamin D's efficacy against COVID-19 severity is limited by insufficient robust trial data and study design heterogeneity.
• * The role of vitamin D in mitigating severe outcomes of coronavirus disease 2019 (COVID-19) requires further clarification.

Purpose of the Study:

• * To summarize the evidence on the impact of vitamin D supplementation on morbidity and mortality in hospitalized COVID-19 patients.
• * To evaluate the effectiveness of vitamin D in reducing the severity of COVID-19 outcomes.

Main Methods:

• * A systematic review of systematic reviews and meta-analyses published between December 2019 and January 2022 was conducted.
• * Searches were performed on PubMed and Google Scholar, identifying 10 eligible reviews.
• * Quality assessment of included reviews was performed using AMSTAR and GRADE tools, with an analysis of primary study overlap.

Main Results:

• * Meta-analysis of seven reviews demonstrated that vitamin D supplementation strongly reduces mortality risk (OR: 0.48, P < 0.001) in COVID-19 patients.
• * Supplementation was associated with reduced need for intensive care (OR: 0.35, P < 0.001) and mechanical ventilation (OR: 0.54, P < 0.001).
• * Findings were robust with low heterogeneity, and qualitative analysis indicated supplements are safe and effective, despite varied study quality.

Conclusions:

• * Vitamin D supplementation is effective in reducing COVID-19 severity, including mortality and critical care needs.
• * Vitamin D should be considered as an adjuvant therapy for COVID-19 management.
• * Further large-scale, robust clinical trials are recommended to solidify these findings.