Trial reportPLoS medicine2021
Vitamin D levels and risk of type 1 diabetes: A Mendelian randomization study.
Trial report in PLoS medicine, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. Cited by 72 papers, 7 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
72 citing papers in PubMed, 7 syntheses or guidelines pooled it, 93 citations in OpenAlex.
- Causal insights into major risk factors for diabetic kidney disease: a comprehensive meta-analysis and Mendelian randomization study.Renal failure · 2025Pooled it
- Micronutrients, Vitamin D, and Inflammatory Biomarkers in COVID-19: A Systematic Review and Meta-analysis of Causal Inference Studies.Nutrition reviews · 2025Pooled it
- Vitamin D and human health: evidence from Mendelian randomization studies.European journal of epidemiology · 2024Pooled it
- Causal validation of the relationship between 35 blood and urine biomarkers and hyperthyroidism: a bidirectional Mendelian randomization study and meta-analysis.Frontiers in endocrinology · 2024Pooled it
- Association between psoriasis and lung cancer: two-sample Mendelian randomization analyses.BMC pulmonary medicine · 2023Pooled it
- Association between enterovirus infection and clinical type 1 diabetes mellitus: systematic review and meta-analysis of observational studies.Epidemiology and infection · 2021Pooled it
- Vitamin D and Type 1 Diabetes Risk: A Systematic Review and Meta-Analysis of Genetic Evidence.Nutrients · 2021Pooled it
- Article
- Neonatal vitamin D levels and autoimmune disorders: a Danish population-based cohort study.European journal of epidemiology · 2026Article
- Vitamin D as a cellular endocrine system: Tissue-specific microcircuits, immune reprogramming, and metabolic resistance.iScience · 2026Review
- Causal Relationship Between Vitamin D and Anxiety and Depression: A Bidirectional Mendelian Randomization Study.Actas espanolas de psiquiatria · 2026Article
- Observational epidemiological studies can mitigate genetic confounding with a genetic relatedness matrix.Proceedings of the National Academy of Sciences of the United States of America · 2026Article
- Increased Levels of the Vitamin D Metabolite Ratio Are Protective Against Progression From Islet Autoimmunity to T1D.The Journal of clinical endocrinology and metabolism · 2026Article
- Vitamin D and Health Outcomes: State-of-the-Art Review of Triangulated Evidence and Ongoing Controversies.Current nutrition reports · 2026Review
- Vitamin D and Mineral Ion Regulation.Advances in experimental medicine and biology · 2026Review
- Vitamin DFrontiers in immunology · 2026Review
- Vitamin D as an Immune Modulator in Systemic Lupus Erythematosus: A Narrative Review.Life (Basel, Switzerland) · 2025Review
- Exploration of the association between 91 inflammatory proteins and immune thrombocytopenia: a two-sample Mendelian randomization analysis.International journal of hematology · 2025Article
- The Role of Vitamin D Supplementation in Type 1, Type 2, and Gestational Diabetes: A Comprehensive Updated Narrative Review.Clinics and practice · 2025Review
- Bidirectional Causal Associations Between Endogenous/Exogenous Antioxidant Levels and Risks of Type 1 and Type 2 Diabetes Mellitus and Three Complications.Food science & nutrition · 2025Article
12 more citing papers are in PubMed but not listed here.
Corrections and comments
- Erratum issued
Authors and funding
9 authors at 7 institutions in 3 countries.
Funding
Abstract
backgroundVitamin D deficiency has been associated with type 1 diabetes in observational studies, but evidence from randomized controlled trials (RCTs) is lacking. The aim of this study was to test whether genetically decreased vitamin D levels are causally associated with type 1 diabetes using Mendelian randomization (MR). METHODS AND
findingsFor our two-sample MR study, we selected as instruments single nucleotide polymorphisms (SNPs) that are strongly associated with 25-hydroxyvitamin D (25OHD) levels in a large vitamin D genome-wide association study (GWAS) on 443,734 Europeans and obtained their corresponding effect estimates on type 1 diabetes risk from a large meta-analysis of 12 type 1 diabetes GWAS studies (Ntot = 24,063, 9,358 cases, and 15,705 controls). In addition to the main analysis using inverse variance weighted MR, we applied 3 additional methods to control for pleiotropy (MR-Egger, weighted median, and mode-based estimate) and compared the respective MR estimates. We also undertook sensitivity analyses excluding SNPs with potential pleiotropic effects. We identified 69 lead independent common SNPs to be genome-wide significant for 25OHD, explaining 3.1% of the variance in 25OHD levels. MR analyses suggested that a 1 standard deviation (SD) decrease in standardized natural log-transformed 25OHD (corresponding to a 29-nmol/l change in 25OHD levels in vitamin D-insufficient individuals) was not associated with an increase in type 1 diabetes risk (inverse-variance weighted (IVW) MR odds ratio (OR) = 1.09, 95% CI: 0.86 to 1.40, p = 0.48). We obtained similar results using the 3 pleiotropy robust MR methods and in sensitivity analyses excluding SNPs associated with serum lipid levels, body composition, blood traits, and type 2 diabetes. Our findings indicate that decreased vitamin D levels did not have a substantial impact on risk of type 1 diabetes in the populations studied. Study limitations include an inability to exclude the existence of smaller associations and a lack of evidence from non-European populations.
conclusionsOur findings suggest that 25OHD levels are unlikely to have a large effect on risk of type 1 diabetes, but larger MR studies or RCTs are needed to investigate small effects.
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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.