ArticleNutrients2021
Distribution and Determinants of Vitamin D-Binding Protein, Total, "Non-Bioavailable", Bioavailable, and Free 25-Hydroxyvitamin D Concentrations among Older Adults.
Article in Nutrients, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 8 papers, 2 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
8 citing papers in PubMed, 2 syntheses or guidelines pooled it, 11 citations in OpenAlex.
- Association of vitamin D in individuals with periodontitis: an updated systematic review and meta-analysis.BMC oral health · 2023Pooled it
- Vitamin D-Binding Protein, Bioavailable, and Free 25(OH)D, and Mortality: A Systematic Review and Meta-Analysis.Nutrients · 2022Pooled it
- Target trial emulation of preconception serum vitamin D status on fertility outcomes: a couples-based approach.Fertility and sterility · 2025Trial
- Impact of COVID-19 Pandemic and Associated Restrictions on Vitamin D Status in a Large Cohort of Italian Children and Adolescents.Medicina (Kaunas, Lithuania) · 2023Article
- The Role of Vitamin D for Human Health: The Challenge of the Right Study Designs and Interpretation.Nutrients · 2023Article
- Article
- Association of circulating serum free bioavailable and total vitamin D with cathelicidin levels among active TB patients and household contacts.Scientific reports · 2023Article
- Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors at 2 institutions in 1 country.
Funding
Abstract
backgroundserum 25-hydroxyvitamin D (25(OH)D) ("total 25 OH(D)") is the most commonly used indicator of vitamin D status. However, 25(OH)D is mostly bound to the vitamin D binding protein (VDBP) or albumin in blood, and it has been suggested that the remaining bioavailable or free 25(OH)D may be more relevant for vitamin D associated health outcomes. We aimed to explore distributions and determinants of VDBP, total, bioavailable, complementary "non-bioavailable", and free 25(OH)D in a large cohort of older adults in Germany.
methodstotal 25(OH)D, VDBP, and albumin concentrations were measured in blood samples of 5899 men and women aged 50-75 years and used to calculate bioavailable (and complementary "non-bioavailable") and free 25(OH)D concentrations. Linear regression models were used to evaluate associations of potential determinants of the various vitamin D biomarkers.
resultsmean concentrations of VDBP, total, non-bioavailable, bioavailable, and free 25(OH)D were 323.6 µg/mL, 49.8 nmol/L, 43.4 nmol/L, 2.5 ng/mL, and 5.7 pg/mL, respectively. Seasonal variations were observed for all markers, with peak values in spring for VDBP and in summer for total, non-bioavailable, bioavailable, and free 25(OH)D. Consistent inverse associations were seen with age and body mass index for all markers, but divergent associations were seen with C-reactive protein. Strong variations by VDBP genotypes were seen for bioavailable and free 25(OH)D, and, in opposite direction for non-bioavailable 25(OH)D.
conclusioncommonalities and differences in determinants of various markers of vitamin D status were observed, which may help to enable a better understanding of their potential role for various vitamin D related health outcomes.
Indexed as
Identifiers
What OpenQuestion 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 OpenQuestion graph.