Trial reportEuropean journal of endocrinology2016
Effects of vitamin D binding protein phenotypes and vitamin D supplementation on serum total 25(OH)D and directly measured free 25(OH)D.
Trial report in European journal of endocrinology, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 42 papers, 1 of them a synthesis 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
42 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Guideline
- Trial
- Serum Vitamin D: Correlates of Baseline Concentration and Response to Supplementation in VITAL-DKD.The Journal of clinical endocrinology and metabolism · 2022Trial
- Total, Bioavailable, and Free 25(OH)D Relationship with Indices of Bone Health in Elderly: A Randomized Controlled Trial.The Journal of clinical endocrinology and metabolism · 2021Trial
- Vitamin D related genetic polymorphisms affect serological response to high-dose vitamin D supplementation in multiple sclerosis.PloS one · 2021Trial
- Effects of High-Dose Vitamin D2 Versus D3 on Total and Free 25-Hydroxyvitamin D and Markers of Calcium Balance.The Journal of clinical endocrinology and metabolism · 2016Trial
- Vitamin D as a cellular endocrine system: Tissue-specific microcircuits, immune reprogramming, and metabolic resistance.iScience · 2026Review
- Disrupted Vitamin D Metabolism in Hepatocellular Carcinoma: Free and Bioavailable 25(OH)D as Novel Biomarkers of Hepatic Reserve and Clinical Risk.Molecules (Basel, Switzerland) · 2026Article
- Genetic determinants of response to vitamin D supplementation.Frontiers in nutrition · 2026Article
- The Quantification of Vitamin D in Humans: A Promising, Non-Invasive and Cost-Effective Method to Measure 25-Hydroxyvitamin D.Biomolecules · 2025Article
- Prediagnostic Vitamin D Status and Colorectal Cancer Survival by Vitamin D Binding Protein Isoforms in US Cohorts.The Journal of clinical endocrinology and metabolism · 2023Article
- Efficacy and safety of high-dose intramuscular vitamin DFrontiers in endocrinology · 2023Article
- Prediagnostic Serum Vitamin D, Vitamin D Binding Protein Isoforms, and Cancer Survival.JNCI cancer spectrum · 2022Article
- Article
- Article
- When Mendelian randomisation fails.BMJ nutrition, prevention & health · 2021Article
- The importance of maternal pregnancy vitamin D for offspring bone health: learnings from the MAVIDOS trial.Therapeutic advances in musculoskeletal disease · 2021Review
- Vitamin D status and disability among patients with multiple sclerosis: a systematic review and meta-analysis.AIMS neuroscience · 2021Review
- Review
- Total, bioavailable and free 25-hydroxyvitamin D levels as functional indicators for bone parameters in healthy children.PloS one · 2021Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
7 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectiveTo determine the relationship between serum total 25-hydroxyvitamin D (25(OH)D), directly measured free 25(OH)D and calculated free 25(OH)D with regard to vitamin D-binding protein (DBP) phenotypes, sex, BMI, age and season, and their interrelationship to vitamin D supplementation. DESIGN, PATIENTS AND
interventionsA randomized controlled trial with 20 000 IU of vitamin D3 per week or placebo for 12 months was designed. A total of 472 subjects, 236 in each of the intervention groups, were included in the analyses.
main outcome measuresBaseline serum concentrations and increases in serum total 25(OH)D, directly measured free 25(OH)D, calculated free 25(OH)D and DBP.
resultsSerum total 25(OH)D and DBP concentrations were significantly lower in subjects with the phenotype Gc2/Gc2 compared to phenotypes with the Gc1S allele, and lower in males compared to females. When using directly measured free 25(OH)D, the differences related to DBP phenotypes and sexes were clearly diminished. All calculated free 25(OH)D concentrations were overestimated compared to the directly measured free 25(OH)D. Serum parathyroid hormone showed an inverse correlation with all vitamin D parameters analyzed. The increases after 12 months of vitamin D supplementation were not significantly different for any of the vitamin D parameters regardless of DBP phenotype, sex or age. Supplementation with vitamin D did not affect serum DBP.
conclusionDirect measurements of free 25(OH)D reduce the differences seen in total 25(OH)D between DBP phenotype groups and sexes, probably caused by differences in DBP concentrations. With conditions affecting serum DBP concentrations, direct measurements of free 25(OH)D should be considered.
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