SynthesisNutrients2022
Effects of Vitamin D Supplementation on COVID-19 Related Outcomes: A Systematic Review and Meta-Analysis.
Synthesis in Nutrients, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 53 papers, 9 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
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.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
53 citing papers in PubMed, 9 syntheses or guidelines pooled it, 90 citations in OpenAlex.
- Effect of the vitamin D supplementation on clinical outcomes and inflammatory status in COVID-19 patients: an umbrella review.BMC nutrition · 2025Pooled it
- Vitamin D Deficiency Meets Hill's Criteria for Causation in SARS-CoV-2 Susceptibility, Complications, and Mortality: A Systematic Review.Nutrients · 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
- Therapeutic effects of vitamin D supplementation on COVID-19 aggravation: a systematic review and meta-analysis of randomized controlled trials.Frontiers in pharmacology · 2024Pooled it
- Pooled it
- Pooled it
- Comment on Hosseini et al. Effects of Vitamin D Supplementation on COVID-19 Related Outcomes: A Systematic Review and Meta-Analysis.Nutrients · 2022Pooled it
- Serum vitamin D levels and COVID-19 during pregnancy: A systematic review and meta-analysis.Clinical nutrition ESPEN · 2022Pooled it
- Trial
- Vitamin D and Health: Establishing Causal Relationships Through Observational Evidence and Hill's Criteria in a Biological Framework.Nutrients · 2026Review
- Vitamin D in Gut and Systemic Immune Tolerance and in Infections' Risk: An International Evidence-Based Consensus Statement.Reviews in endocrine & metabolic disorders · 2026Review
- Impact of a Research Integrity Assessment (RIA) of Randomized Controlled Trials Included in Interventional COVID-19 Systematic Reviews: A Meta-Epidemiological Study.Cochrane evidence synthesis and methods · 2026Article
- Integrative Vitamin D-Inflammatory-Coagulation Biomarker Index Predicts COVID-19 Severity: Development and Validation of the Vitamin D Inflammatory Burden Score (VDIBS).International journal of molecular sciences · 2026Article
- Vitamin D and COVID-19: Clinical Evidence and Immunological Insights.Life (Basel, Switzerland) · 2025Review
- Vitamin D Status and Incidence of SARS-CoV-2 Reinfections in the Borriana COVID-19 Cohort: A Population-Based Prospective Cohort Study.Tropical medicine and infectious disease · 2025Article
- Comparison of the role of vitamin D in normal organs and those affected by COVID-19.International journal of medical sciences · 2025Review
- Article
- The Role of Vitamins, Magnesium, and Trace Elements in COVID-19 Treatment and Post-COVID-19 Rehabilitation: An Updated Overview.Current medicinal chemistry · 2025Review
- Vitamin D Deficiency as a Contributing Factor to Chronic Rhinitis in Middle-Aged and Older Adults: An Epidemiological Study.Nutrients · 2024Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors at 1 institution in 1 country.
Funding
Abstract
The COVID-19 outbreak has rapidly expanded to a global pandemic; however, our knowledge is limited with regards to the protective factors against this infection. The aim of this systematic literature review and meta-analysis was to evaluate the impact of vitamin D supplementation on COVID-19 related outcomes. A systematic search of relevant papers published until January 2022 was conducted to identify randomized controlled trials (RCTs) and non-randomized studies of intervention (NRISs). The primary outcomes included the risk of COVID-19 infection (primary prevention studies on uninfected individuals), hospital admission (secondary prevention studies on mild COVID-19 cases), and ICU admission and mortality rate (tertiary prevention studies on hospitalized COVID-19 patients). We identified five studies (one RCT, four NRISs) on primary prevention, with five (two RCTs, three NRISs) on secondary prevention, and 13 (six RCTs, seven NRISs) on tertiary prevention. Pooled analysis showed no significant effect on the risk of COVID-19 infection. No meta-analysis was possible on hospitalization risk due to paucity of data. Vitamin D supplementation was significantly associated with a reduced risk of ICU admission (RR = 0.35, 95% CI: 0.20, 0.62) and mortality (RR = 0.46, 95% CI: 0.30, 0.70). Vitamin D supplementation had no significant impact on the risk of COVID-19 infection, whereas it showed protective effects against mortality and ICU admission in COVID-19 patients.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.