ReviewEndocrine connections2020
Why do so many trials of vitamin D supplementation fail?
Review in Endocrine connections, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 36 papers, 4 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
36 citing papers in PubMed, 4 syntheses or guidelines pooled it, 65 citations in OpenAlex.
- High-dose oral vitamin D supplementation for prevention of infections in children aged 0 to 59 months: a systematic review and meta-analysis.Nutrition reviews · 2024Pooled it
- Associations of Prenatal Vitamin D status with Oral Health in Offspring: A Systematic Review.Oral health & preventive dentistry · 2022Pooled it
- Pooled it
- Perspective: Vitamin D supplementation prevents rickets and acute respiratory infections when given as daily maintenance but not as intermittent bolus: implications for COVID-19.Clinical medicine (London, England) · 2021Pooled it
- Vitamin D and Health: Establishing Causal Relationships Through Observational Evidence and Hill's Criteria in a Biological Framework.Nutrients · 2026Review
- Genomic profiling of active vitamin D colonic responses in African- and European-Americans identifies an ancestry-related regulatory variant of POLB.PLoS genetics · 2026Article
- Review
- Review
- Article
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- Vitamin D beyond the blood: Tissue distribution of vitamin D metabolites after supplementation.Life sciences · 2024Review
- Clinical characteristics and serum 25-hydroxyvitamin D levels in children with febrile seizures in China.Scientific reports · 2024Article
- Sex differences in the association between vitamin D and prediabetes in adults: A cross-sectional study.Nutrition & diabetes · 2024Article
- Review
- Discordant Health Implications and Molecular Mechanisms of Vitamin D in Clinical and Preclinical Studies of Prostate Cancer: A Critical Appraisal of the Literature Data.International journal of molecular sciences · 2024Review
- Article
- Effects of vitamin D and L-cysteine cosupplementation on circulating bioavailable and total 25-hydroxy-vitamin D, the free/total testosterone ratio and inflammatory biomarkers in healthy vitamin D-deficient African Americans: a placebo-controlled double-blind clinical trial.BMJ nutrition, prevention & health · 2024Article
- Vitamin D and COVID-19: where are we now?Postgraduate medicine · 2023Review
- Psoriasis immunometabolism: progress on metabolic biomarkers and targeted therapy.Frontiers in molecular biosciences · 2023Review
- Rapidly Increasing Serum 25(OH)D Boosts the Immune System, against Infections-Sepsis and COVID-19.Nutrients · 2022Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
1 author at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Our knowledge of vitamin D has come a long way since the 100 years it took for doctors to accept, between 1860 and 1890, that both sunlight and cod liver oil (a well-known folk remedy) cured and prevented rickets. Vitamins D2/D3 were discovered exactly a hundred years ago, and over the last 50 years vitamin D has been found to have many effects on virtually all human tissues and not just on bone health, while mechanisms affecting the actions of vitamin D at the cellular level are increasingly understood, but deficiency persists globally. Observational studies in humans have shown that better provision of vitamin D is strongly associated, dose-wise, with reductions in current and future health risks in line with the known actions of vitamin D. Randomised controlled trials, commonly accepted as providing a 'gold standard' for assessing the efficacy of new forms of treatment, have frequently failed to provide supportive evidence for the expected health benefits of supplementation. Such RCTs, however, have used designs evolved for testing drugs while vitamin D is a nutrient; the appreciation of this difference is critical to identifying health benefits from existing RCT data and for improving future RCT design. This report aims, therefore, to provide a brief overview of the evidence for a range of non-bony health benefits of vitamin D repletion; to discuss specific aspects of vitamin D biology that can confound RCT design and how to allow for them.
Indexed as
Identifiers
What Socratic holds
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 Socratic graph.