{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T14:35:20Z","timestamp":1787668520076,"version":"build-2736575974"},"reference-count":32,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2022,1,24]],"date-time":"2022-01-24T00:00:00Z","timestamp":1642982400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"The Swedish Society for Dermatology and Venereology","award":["Application year 2016"],"award-info":[{"award-number":["Application year 2016"]}]},{"name":"The G\u00f6teborg Medical Society","award":["59029, 884701 and 935700"],"award-info":[{"award-number":["59029, 884701 and 935700"]}]},{"name":"The Welander-Finsen Foundation","award":["2238, 2810, 3302"],"award-info":[{"award-number":["2238, 2810, 3302"]}]},{"name":"The Swedish Psoriasis Association","award":["Application year 2018"],"award-info":[{"award-number":["Application year 2018"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>High levels of vitamin D-binding protein (DBP) have been reported in patients with psoriasis and the possibility of DBP as a marker of inflammation has been discussed. Furthermore, high DBP levels might negatively affect free 25(OH)D concentrations. According to the free hormone hypothesis, only the free fraction of a steroid hormone is capable of exerting biological action. Thus, free 25(OH)D level could be a better biomarker of vitamin D status than total 25(OH)D level. The objectives of this study were to identify the strongest determinants for DBP levels and to test the free hormone hypothesis for vitamin D in psoriasis. Additionally, we also aimed to investigate correlations between directly measured free 25(OH)D levels in serum and psoriasis disease severity compared to total 25(OH)D levels. This was a retrospective cross-sectional study including 40 bio-na\u00efve patients with mild to severe plaque psoriasis. Psoriasis disease severity was evaluated using high sensitivity C-reactive protein (hsCRP), Psoriasis Area Severity Index (PASI) and visual analogue scale (VAS). Vitamin D metabolites including directly measured free 25(OH)D and serum DBP levels were measured. DBP levels were higher in patients with self-reported arthropathy than those without irrespective of confounding factors like sex, age and body weight. Total and free 25(OH)D levels correlated well (\u03c1 = 0.77, p &lt; 0.0001) and both were inversely correlated to intact parathyroid hormone (iPTH) (\u03c1 = \u22120.33, p = 0.038 for total 25(OH)D and \u03c1 = \u22120.40, p = 0.010 for free 25(OH)D). Only total 25(OH)D correlated to serum calcium levels (\u03c1 = 0.32, p = 0.047). No correlations between any of the vitamin D metabolites and psoriasis disease severity were observed. In conclusion, DBP might be a new inflammatory biomarker in psoriasis, especially in psoriatic arthritis. Total 25(OH)D was a reliable measure for vitamin D status in this psoriasis cohort. However, evaluation of free 25(OH)D in patients with psoriatic disease and multiple co-morbidities and\/or ongoing biologic treatment should be considered.<\/jats:p>","DOI":"10.3390\/ijms23031302","type":"journal-article","created":{"date-parts":[[2022,1,25]],"date-time":"2022-01-25T20:38:58Z","timestamp":1643143138000},"page":"1302","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Vitamin D-Binding Protein and the Free Hormone Hypothesis for Vitamin D in Bio-Na\u00efve Patients with Psoriasis"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5899-5958","authenticated-orcid":false,"given":"Maria Siekkeri","family":"Vandikas","sequence":"first","affiliation":[{"name":"Department of Dermatology and Venereology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE-413 45 Gothenburg, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kerstin","family":"Landin-Wilhelmsen","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, SE-413 45 Gothenburg, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martin","family":"Gillstedt","sequence":"additional","affiliation":[{"name":"Department of Dermatology and Venereology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE-413 45 Gothenburg, Sweden"},{"name":"Department of Dermatology and Venereology, Sahlgrenska University Hospital, Region V\u00e4stra G\u00f6taland, SE-413 45 Gothenburg, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Amra","family":"Osmancevic","sequence":"additional","affiliation":[{"name":"Department of Dermatology and Venereology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE-413 45 Gothenburg, Sweden"},{"name":"Department of Dermatology and Venereology, Sahlgrenska University Hospital, Region V\u00e4stra G\u00f6taland, SE-413 45 Gothenburg, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,1,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"383","DOI":"10.1111\/ijd.12790","article-title":"The role of vitamin D in psoriasis: A review","volume":"54","author":"Soleymani","year":"2015","journal-title":"Int. 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