{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,22]],"date-time":"2026-07-22T21:13:49Z","timestamp":1784754829925,"version":"3.55.0"},"reference-count":28,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2024,3,14]],"date-time":"2024-03-14T00:00:00Z","timestamp":1710374400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Austrian National Bank","award":["13878"],"award-info":[{"award-number":["13878"]}]},{"name":"Austrian National Bank","award":["13905"],"award-info":[{"award-number":["13905"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Circulating 25-hydroxyvitamin D (25(OH)D) is the generally accepted indicator of vitamin D status. Since hydroxylation of 25(OH)D to 24-25-dihydroxyvitamin D (24,25(OH)2D) is the first step of its catabolism, it has been suggested that a low 24,25(OH)D level and a low vitamin D metabolite ratio (VMR), i.e., 24,25(OH)2D divided by 25(OH)D, may indicate high vitamin D requirements and provide additional diagnostic information beyond serum 25(OH)D. We, therefore, evaluated whether the classification of \u201cfunctional vitamin D deficiency\u201d, i.e., 25(OH)D below 50 nmol\/L, 24,25(OH)2D below 3 nmol\/L and a VMR of less than 4%, identifies individuals who benefit from vitamin D supplementation. In participants of the Styrian Vitamin D Hypertension trial, a randomized controlled trial (RCT) in 200 hypertensive patients with serum 25(OH)D below 75 nmol\/L, who received either 2.800 international units of vitamin D per day or placebo over 8 weeks, 51 participants had functional vitamin D deficiency. In these individuals, there was no treatment effect of vitamin D supplementation on various parameters of bone metabolism and cardiovascular risk except for a significant effect on parathyroid hormone (PTH) and expected changes in vitamin D metabolites. In conclusion, a low vitamin D metabolite profile did not identify individuals who significantly benefit from vitamin D supplementation with regard to bone markers and cardiovascular risk factors. The clinical significance of functional vitamin D deficiency requires further evaluation in large vitamin D RCTs.<\/jats:p>","DOI":"10.3390\/nu16060839","type":"journal-article","created":{"date-parts":[[2024,3,15]],"date-time":"2024-03-15T14:05:25Z","timestamp":1710511525000},"page":"839","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Classification of Vitamin D Status Based on Vitamin D Metabolism: A Randomized Controlled Trial in Hypertensive Patients"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8653-0779","authenticated-orcid":false,"given":"Sieglinde","family":"Zelzer","sequence":"first","affiliation":[{"name":"Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, 8036 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andreas","family":"Meinitzer","sequence":"additional","affiliation":[{"name":"Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, 8036 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1173-0928","authenticated-orcid":false,"given":"Dietmar","family":"Enko","sequence":"additional","affiliation":[{"name":"Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, 8036 Graz, Austria"},{"name":"Institute of Clinical Chemistry and Laboratory Medicine, Hospital Hochsteiermark, Vordernberger Stra\u00dfe 42, 8700 Leoben, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martin H.","family":"Keppel","sequence":"additional","affiliation":[{"name":"Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, 8036 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Markus","family":"Herrmann","sequence":"additional","affiliation":[{"name":"Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, 8036 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Verena","family":"Theiler-Schwetz","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, Division of Endocrinology and Diabetology, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christian","family":"Trummer","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, Division of Endocrinology and Diabetology, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lisa","family":"Schmitt","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, Division of Endocrinology and Diabetology, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andreas","family":"Tomaschitz","sequence":"additional","affiliation":[{"name":"Health Center Trofaiach-G\u00f6ssgrabenstrasse, 8793 Trofaiach, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1767-555X","authenticated-orcid":false,"given":"Patrick","family":"Sadoghi","sequence":"additional","affiliation":[{"name":"Department of Orthopedics and Trauma, Medical University of Graz, Auenbruggerplatz 5, 8036 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jutta","family":"Dierkes","sequence":"additional","affiliation":[{"name":"Mohn Nutrition Research Laboratory, Centre for Nutrition, Department of Clinical Medicine, University of Bergen, 5020 Bergen, Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8475-7112","authenticated-orcid":false,"given":"Pawel","family":"Pludowski","sequence":"additional","affiliation":[{"name":"Department of Biochemistry, Radioimmunology and Experimental Medicine, The Children\u2019s Memorial Health Institute, 04-730 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6085-6554","authenticated-orcid":false,"given":"Armin","family":"Zittermann","sequence":"additional","affiliation":[{"name":"Clinic for Thoracic and Cardiovascular Surgery, Herz- und Diabeteszentrum Nordrhein-Westfalen (NRW), Ruhr University Bochum, 32545 Bad Oeynhausen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Winfried","family":"M\u00e4rz","sequence":"additional","affiliation":[{"name":"Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, 8036 Graz, Austria"},{"name":"SYNLAB Academy, Synlab Holding Deutschland GmbH, 68159 Mannheim, Germany"},{"name":"Vth Department of Medicine (Nephrology, Hypertensiology, Rheumatology, Endocrinology, Diabetology, Lipidology), Medical Faculty Mannheim, University of Heidelberg, 68167 Mannheim, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stefan","family":"Pilz","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, Division of Endocrinology and Diabetology, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,3,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"466","DOI":"10.1038\/nrendo.2017.31","article-title":"Comparative analysis of nutritional guidelines for vitamin D","volume":"13","author":"Bouillon","year":"2017","journal-title":"Nat. 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