ArticleBMC geriatrics2017
Vitamin D supplementation as a potential cause of U-shaped associations between vitamin D levels and negative health outcomes: a decision tree analysis for risk of frailty.
Article in BMC geriatrics, 2017. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 15 papers, 2 of them syntheses that pooled it.
What it found
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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
15 citing papers in PubMed, 2 syntheses or guidelines pooled it, 17 citations in OpenAlex.
- Vitamin D deficiency in nursing home residents: a systematic review.Nutrition reviews · 2023Pooled it
- Vitamin D as a Biomarker of Ill Health among the Over-50s: A Systematic Review of Cohort Studies.Nutrients · 2019Pooled it
- High-dose vitamin DRespiratory research · 2024Trial
- OralNutrients · 2026Article
- Vitamin D as a cellular endocrine system: Tissue-specific microcircuits, immune reprogramming, and metabolic resistance.iScience · 2026Review
- Joint association of serum 25-hydroxyvitamin D concentration and body mass index on the acceleration of clinical biomarker-based biological aging.The journals of gerontology. Series A, Biological sciences and medical sciences · 2026Article
- Vitamin D deficiency among apparently healthy adults in northern China: behavioral correlates and an indoor-lifestyle framework.Frontiers in public health · 2026Article
- Optimizing serum 25(OH)D levels to mitigate the risk of age-related ocular diseases: insights from a large-scale prospective cohort study.Nutrition journal · 2025Article
- The Co-Existence of Hypovitaminosis D and Diabetes Mellitus Triples the Incidence of Severe Coronary Artery Disease in Women.Journal of clinical medicine · 2024Article
- Very Low and High Levels of Vitamin D Are Associated with Shorter Leukocyte Telomere Length in 148,321 UK Biobank Participants.Nutrients · 2023Article
- Vitamin D and Bone Health of Older Adults within Care Homes: An Observational Study.Nutrients · 2022Observational
- Vitamin D Deficiency in Older Patients-Problems of Sarcopenia, Drug Interactions, Management in Deficiency.Nutrients · 2021Review
- Vitamin D supplementation: upper limit for safety revisited?Aging clinical and experimental research · 2021Review
- Simulation of Physicochemical and Pharmacokinetic Properties of Vitamin DPharmaceuticals (Basel, Switzerland) · 2020Article
- Prolonging healthy aging: Longevity vitamins and proteins.Proceedings of the National Academy of Sciences of the United States of America · 2018Review
Corrections and comments
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Authors and funding
3 authors at 2 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundA recent controversy in vitamin D research is a "U-shaped association", with elevated disease risks at both high and low 25-hydroxyvitamin D (25 (OH) D) levels.
methodsThis is a cross-sectional study of 238 male nursing home veterans in Hawaii. Classification and regression tree (CART) analysis identified groups based on 25 (OH) D and vitamin D supplementation for frailty risk. Characteristics were examined and compared across the groups using logistic regression and receiver operating characteristic (ROC) curve analyses.
resultsCART analysis identified three distinct groups: vitamin D supplement users (n = 86), non-users with low vitamin D (n = 55), and non-users with high vitamin D (n = 97). Supplement users were the most frail, but had high mean 25 (OH) D of 26.6 ng/mL, which was compatible with 27.1 ng/mL in non-users with high vitamin D, while mean 25 (OH) D of non-users with low vitamin D was 11.7 ng/mL. Supplement users and non-users with low vitamin D were significantly more likely to be frail (odds ratio (OR) = 9.90, 95% CI = 2.18-44.86, p = 0.003; OR = 4.28, 95% CI = 1.44-12.68, p = 0.009, respectively), compared with non-users with low vitamin D. ROC curve analysis showed the three groups significantly predicted frailty (area under the curve = 0.73), with sensitivity of 64.4% and specificity of 76.7%, while 25 (OH) D did not predict frailty.
conclusionsIn these nursing home veterans, vitamin D supplement users were the most frail but with high 25 (OH) D. This can potentially be a cause of U-shaped associations between vitamin D levels and negative health outcomes.
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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.