Kojima, G;
Iliffe, S;
Tanabe, M;
(2017)
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.
BMC Geriatrics
, 17
, Article 236. 10.1186/s12877-017-0631-0.
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Abstract
Background: A 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. Methods: This 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. Results: CART 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. Conclusions: In 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.
| Type: | Article |
|---|---|
| Title: | 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 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1186/s12877-017-0631-0 |
| Publisher version: | http://doi.org/10.1186/s12877-017-0631-0 |
| Language: | English |
| Additional information: | © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. |
| Keywords: | Frailty, Vitamin D, Vitamin D deficiency, Vitamin D supplementation, Nursing home |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Epidemiology and Health UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Epidemiology and Health > Primary Care and Population Health |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10024307 |
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