Vitamin D and SARS-CoV2 infection, severity and mortality: A systematic review and meta-analysis

Study answer

What this study found

Vitamin D supplementation was associated with lower COVID-19 severity and mortality, while low baseline vitamin D status was associated with higher infection, severity, and mortality risk. For severity, the pooled association was SRR 0.38 (95% CI 0.20-0.72; 6 studies), and for mortality it was SRR 0.35 (95% CI 0.17-0.70; 8 studies), both indicating reduced risk with supplementation. Low baseline vitamin D was associated with higher infection risk, SRR 2.18 (95% CI 1.55-3.06). The authors concluded that these findings are suggestive but not causal, and that randomized controlled trials are…

Study & population

Systematic review and meta-analysis of studies in individuals tested for SARS-CoV-2 or diagnosed with COVID-19, including hospitalized and non-hospitalized populations from multiple regions such as Asia, the United States, and Europe.

Intervention

Vitamin D supplementation was evaluated in heterogeneous regimens across included studies, including calcifediol and vitamin D3 (cholecalciferol).

Key limitation

The evidence was heterogeneous and relied heavily on observational data, limiting causal inference.

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Original abstract