SynthesisPloS one2022
Vitamin D and SARS-CoV2 infection, severity and mortality: A systematic review and meta-analysis.
Synthesis in PloS one, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 46 papers, 8 of them syntheses that pooled it.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
46 citing papers in PubMed, 8 syntheses or guidelines pooled it, 83 citations in OpenAlex.
- Vitamin D Deficiency Meets Hill's Criteria for Causation in SARS-CoV-2 Susceptibility, Complications, and Mortality: A Systematic Review.Nutrients · 2025Pooled it
- Pooled it
- Effect of vitamin D supplementation on COVID-19 outcomes: an umbrella review of systematic reviews.Frontiers in nutrition · 2025Pooled it
- Pharmacological evaluation of vitamin D in COVID-19 and long COVID-19: recent studies confirm clinical validation and highlight metformin to improve VDR sensitivity and efficacy.Inflammopharmacology · 2024Pooled it
- The impact of supplementing vitamin D through different methods on the prognosis of COVID-19 patients: a systematic review and meta-analysis.Frontiers in nutrition · 2024Pooled it
- Pooled it
- Effect of vitamin D supplementation on COVID-19 patients: A systematic review and meta-analysis.Frontiers in nutrition · 2023Pooled it
- Vitamin D supplementation for the treatment of COVID-19: A systematic review and meta-analysis of randomized controlled trials.Frontiers in immunology · 2022Pooled it
- Vitamin D Supplementation and Clinical Outcomes in Severe COVID-19 Patients-Randomized Controlled Trial.Nutrients · 2023Trial
- Vitamin D and Health: Establishing Causal Relationships Through Observational Evidence and Hill's Criteria in a Biological Framework.Nutrients · 2026Review
- COVID-19 and long-term risk of incident laboratory-defined micronutrient deficiency in patients with type 2 diabetes: a multicenter propensity score-matched cohort study.Frontiers in nutrition · 2026Article
- Association between 25(OH)D levels and clinical outcomes in patients infected with SARS-CoV-2: a cross-sectional study.Scientific reports · 2025Article
- Identification of Priority Nutrients in the US: Targeting Malnutrition to Address Diet-Related Disease Across the Lifespan.Nutrients · 2025Article
- Review
- Cholecalciferol (vitamin D3): efficacy, safety, and implications in public health.Frontiers in nutrition · 2025Review
- Do serum vitamins, carotenoids, and retinyl esters influence mortality in osteoarthritis? Insights from a nationally representative study.Frontiers in nutrition · 2025Article
- Impact of vitamin D on COVID-19 and other viral diseases.World journal of virology · 2024Article
- Efficacy of vitamin D supplementation in the treatment of patients with COVID-19: a systematic review and meta-analysis of randomized controlled trials.Annals of medicine and surgery (2012) · 2024Review
- Impact of the COVID-19 lockdown on the vitamin D status of people in the West of Ireland.Irish journal of medical science · 2024Article
- High-dose vitamin D supplementation in patients with COVID-19: A meta-analysis of randomized controlled trials.Food science & nutrition · 2024Article
Corrections and comments
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Authors and funding
19 authors at 4 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
To assess the evidence on SARS-CoV2 infection and Covid-19 in relation to deficiency and supplementation of vitamin D, we conducted a systematic review up to April 2021. We summarised data from 38 eligible studies, which presented risk estimates for at least one endpoint, including two RCT and 27 cohort-studies: 205565 patients with information on 25OHD status and 2022 taking vitamin D supplementation with a total of 1197 admitted to the ICU or who needed invasive mechanical ventilation or intubation and hospital stay, and more than 910 Covid-19 deaths. Primary outcomes were severity and mortality and the main aim was to evaluate the association with vitamin D supplementation. Random effects models showed that supplementation was associated with a significant lower risk of both Covid-19 severe disease (SRR 0.38, 95% CI 0.20-0.72, 6 studies) and mortality (SRR 0.35, 95% CI 0.17-0.70, 8 studies). There were no statistically significant dose differences between studies: summary estimates with regular doses remain statistically significant, suggesting that higher doses are not necessary. For patients on vitamin D supplementation, a greater reduction in mortality risk emerged in older individuals and at higher latitudes. Regarding the quality of studies, assessed using the New Castle-Ottawa quality scale, the analysis revealed in most cases no statistically significant differences between low, medium or high quality studies. We found significant associations of vitamin D supplementation with Covid-19, encompassing risks of disease worsening and mortality, especially in seasons characterized by 25OHD deficiency and with not severe patients. Dedicated randomized clinical studies are encouraged to confirm these results.
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