{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T04:46:27Z","timestamp":1782362787215,"version":"3.54.5"},"reference-count":41,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2022,12,16]],"date-time":"2022-12-16T00:00:00Z","timestamp":1671148800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Department of Public Health, Faculty of Medicine, University of Ljubljana research program","award":["No. P3-0360"],"award-info":[{"award-number":["No. P3-0360"]}]},{"name":"Slovenian research programme for comprehensive cancer control SLORApro and University Medical Centre Ljubljana, The Division of Gynaecology and Obstetrics, research program","award":["No. P3-0360 P3-0124"],"award-info":[{"award-number":["No. P3-0360 P3-0124"]}]}],"content-domain":{"domain":["www.mdpi.com"],"crossmark-restriction":true},"short-container-title":["Nutrients"],"abstract":"<jats:p>The objective of our study was to evaluate vitamin D status and its predictors in Slovenian premenopausal and postmenopausal women. A cross-sectional study was carried out between 1 March 2021 and 31 May 2021. A total of 319 healthy women from the Central Slovenian region aged between 44 and 65 were recruited; 176 were included in the final analysis. The vitamin D status was determined by measuring the total 25-Hydroxycholecalciferol (25(OH)D) concentration, vitamin D binding protein (DBP), and albumin and calculating the bioavailable 25(OH)D and free 25(OH)D. For the calculation of bioavailable and free 25(OH)D, we developed a new online calculator. The Endocrine Society\u2019s thresholds for vitamin D deficiency and insufficiency were used; 29.0% of premenopausal and 24.4% of postmenopausal subjects were found to be vitamin D deficient (total 25(OH)D &lt; 50 nmol\/L); 76.8% of the premenopausal and 61.7% of postmenopausal subjects were found to have insufficient levels (total 25(OH)D &lt; 75 nmol\/L). Premenopausal women had 11.8% lower total 25(OH)D, 32.2% lower bioavailable 25(OH)D, and 25.2% higher DBP than postmenopausal women. The most important predictors of vitamin D status were vitamin D supplementation and time spent in the sun. Contrary to similar studies, the vitamin D status in Slovenian postmenopausal women was significantly better than in premenopausal women. In postmenopausal women, the measurement of free or bioavailable 25(OH)D instead of the total 25(OH)D could be advantageous.<\/jats:p>","DOI":"10.3390\/nu14245349","type":"journal-article","created":{"date-parts":[[2022,12,19]],"date-time":"2022-12-19T07:59:21Z","timestamp":1671436761000},"page":"5349","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Assessment of Vitamin D Status in Slovenian Premenopausal and Postmenopausal Women, Using Total, Free, and Bioavailable 25-Hydroxyvitamin D (25(OH)D)"],"prefix":"10.3390","volume":"14","author":[{"given":"Vid","family":"Vi\u010di\u010d","sequence":"first","affiliation":[{"name":"Faculty of Health Sciences, Chair of Biomedicine in Healthcare, University of Ljubljana, Zdravstvena pot 5, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andreja","family":"Kukec","sequence":"additional","affiliation":[{"name":"National Institute of Public Health, Trubarjeva 2, 1000 Ljubljana, Slovenia"},{"name":"Faculty of Medicine, Chair of Public Health, University of Ljubljana, Zalo\u0161ka 4, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sa\u0161a","family":"Kugler","sequence":"additional","affiliation":[{"name":"National Institute of Public Health, Trubarjeva 2, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9088-2382","authenticated-orcid":false,"given":"Ksenija","family":"Ger\u0161ak","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, Division of Obstetrics and Gynaecology, University of Ljubljana, \u0160lajmerjeva 3, 1000 Ljubljana, Slovenia"},{"name":"Clinic of Gynaecology and Obstetrics, University Medical Centre Ljubljana, \u0160lajmerjeva 3, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1839-2415","authenticated-orcid":false,"given":"Jo\u0161ko","family":"Osredkar","sequence":"additional","affiliation":[{"name":"Institute of Clinical Chemistry and Biochemistry, University Medical Centre Ljubljana, Njego\u0161eva 4, 1000 Ljubljana, Slovenia"},{"name":"Faculty of Pharmacy, University of Ljubljana, A\u0161ker\u010deva 7, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ru\u017ea","family":"Pandel Miku\u0161","sequence":"additional","affiliation":[{"name":"Faculty of Health Sciences, Chair of Biomedicine in Healthcare, University of Ljubljana, Zdravstvena pot 5, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,12,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"266","DOI":"10.1056\/NEJMra070553","article-title":"Vitamin D Deficiency","volume":"357","author":"Holick","year":"2007","journal-title":"N. Engl. J. Med."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"654","DOI":"10.3945\/jn.113.189811","article-title":"Including Food 25-Hydroxyvitamin D in Intake Estimates May Reduce the Discrepancy between Dietary and Serum Measures of Vitamin D Status","volume":"144","author":"Taylor","year":"2014","journal-title":"J. Nutr."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"nzz086","DOI":"10.1093\/cdn\/nzz086","article-title":"Challenges to Quantify Total Vitamin Activity: How to Combine the Contribution of Diverse Vitamers?","volume":"3","author":"Jakobsen","year":"2019","journal-title":"Curr. Dev. Nutr."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Vrani\u0107, L., Mikola\u0161evi\u0107, I., and Mili\u0107, S. (2019). Vitamin D Deficiency: Consequence or Cause of Obesity?. Medicina, 55.","DOI":"10.3390\/medicina55090541"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"901","DOI":"10.1016\/j.ecl.2017.07.013","article-title":"Current Controversies: Are Free Vitamin Metabolite Levels a More Accurate Assessment of Vitamin D Status than Total Levels?","volume":"46","author":"Bikle","year":"2017","journal-title":"Endocrinol. Metab. Clin. N. Am."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1016\/j.jsbmb.2017.11.014","article-title":"Why Should We Measure Free 25(OH) Vitamin D?","volume":"180","author":"Tsuprykov","year":"2018","journal-title":"J. Steroid Biochem. Mol. Biol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"259","DOI":"10.3389\/fendo.2018.00259","article-title":"Deconvoluting the Biological Roles of Vitamin D-Binding Protein During Pregnancy: A Both Clinical and Theoretical Challenge","volume":"9","author":"Karras","year":"2018","journal-title":"Front. Endocrinol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2159","DOI":"10.1172\/JCI106710","article-title":"The Turnover and Transport of Vitamin D and of a Polar Metabolite with the Properties of 25-Hydroxycholecalciferol in Human Plasma","volume":"50","author":"Smith","year":"1971","journal-title":"J. Clin. Investig."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"317","DOI":"10.3389\/fendo.2019.00317","article-title":"Vitamin D Binding Protein, Total and Free Vitamin D Levels in Different Physiological and Pathophysiological Conditions","volume":"10","author":"Bikle","year":"2019","journal-title":"Front. Endocrinol."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Hribar, M., Hristov, H., Gregori\u010d, M., Blaznik, U., Zaletel, K., Oblak, A., Osredkar, J., Ku\u0161ar, A., \u017dmitek, K., and Rogelj, I. (2020). Nutrihealth Study: Seasonal Variation in Vitamin D Status Among the Slovenian Adult and Elderly Population. Nutrients, 12.","DOI":"10.3390\/nu12061838"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/j.maturitas.2014.06.003","article-title":"Vitamin D and Menopause\u2014A Narrative Review","volume":"79","author":"Lerchbaum","year":"2014","journal-title":"Maturitas"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"693","DOI":"10.1359\/jbmr.081209","article-title":"Vitamin D Status, Parathyroid Function, Bone Turnover, and BMD in Postmenopausal Women with Osteoporosis: Global Perspective","volume":"24","author":"Kuchuk","year":"2009","journal-title":"J. Bone Miner. Res."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Chalcraft, J.R., Cardinal, L.M., Wechsler, P.J., Hollis, B.W., Gerow, K.G., Alexander, B.M., Keith, J.F., and Larson-Meyer, D.E. (2020). Vitamin D Synthesis Following a Single Bout of Sun Exposure in Older and Younger Men and Women. Nutrients, 12.","DOI":"10.3390\/nu12082237"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"537","DOI":"10.1172\/JCI113915","article-title":"Effects of Estrogen on Circulating \u201cFree\u201d and Total 1,25-Dihydroxyvitamin D and on the Parathyroid-Vitamin D Axis in Postmenopausal Women","volume":"83","author":"Cheema","year":"1989","journal-title":"J. Clin. Investig."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"3370","DOI":"10.1210\/jc.2016-1658","article-title":"Use of Estrogen-Containing Contraception Is Associated With Increased Concentrations of 25-Hydroxy Vitamin D","volume":"101","author":"Harmon","year":"2016","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"3470","DOI":"10.3390\/nu5093470","article-title":"Increased Plasma Concentrations of Vitamin D Metabolites and Vitamin D Binding Protein in Women Using Hormonal Contraceptives: A Cross-Sectional Study","volume":"5","author":"Moller","year":"2013","journal-title":"Nutrients"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"936","DOI":"10.4158\/EP15623.OR","article-title":"Vitamin D-Binding Protein In Healthy Pre- And Postmenopausal Women: Relationship With Estradiol Concentrations","volume":"21","author":"Pop","year":"2015","journal-title":"Endocr. Pract."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"232","DOI":"10.1210\/edrv-10-3-232","article-title":"The Free Hormone Hypothesis: A Physiologically Based Mathematical Model","volume":"10","author":"Mendel","year":"1989","journal-title":"Endocr. Rev."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Abidin, N.Z., and Mitra, S.R. (2020). Total vs. Bioavailable: Determining a Better 25(OH)D Index in Association with Bone Density and Muscle Mass in Postmenopausal Women. Metabolites, 11.","DOI":"10.3390\/metabo11010023"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1186\/s13690-018-0282-4","article-title":"European Health Examination Surveys\u2014A Tool for Collecting Objective Information about the Health of the Population","volume":"76","author":"Tolonen","year":"2018","journal-title":"Arch. Public Health"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"148","DOI":"10.1214\/aoms\/1177705148","article-title":"Snowball Sampling","volume":"32","author":"Goodman","year":"1961","journal-title":"Ann. Math. Statist."},{"key":"ref_22","unstructured":"WHO (1996). Research on the Menopause in the 1990s. Report of a WHO Scientific Group. World Health Organ. Tech. Rep. Ser., 866, 1\u2013107."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"S97","DOI":"10.1079\/BJN2001345","article-title":"Vitamin D Status and Its Adequacy in Healthy Danish Perimenopausal Women: Relationships to Dietary Intake, Sun Exposure and Serum Parathyroid Hormone","volume":"86","author":"Brot","year":"2001","journal-title":"Br. J. Nutr."},{"key":"ref_24","unstructured":"Jeretina, B. (2019). Dejavniki Vpliva Na Pojav Prezgodnje Menopavze: Magistrsko Delo, Zdravstvena Fakulteta v Ljubljani."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"49","DOI":"10.21315\/eimj2019.11.2.6","article-title":"ABC of Content Validation and Content Validity Index Calculation","volume":"11","author":"Yusoff","year":"2019","journal-title":"Educ. Med. J."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"3666","DOI":"10.1210\/jcem.84.10.6079","article-title":"A Critical Evaluation of Simple Methods for the Estimation of Free Testosterone in Serum","volume":"84","author":"Vermeulen","year":"1999","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1153","DOI":"10.1210\/jc.2011-2601","article-title":"Guidelines for Preventing and Treating Vitamin D Deficiency and Insufficiency Revisited","volume":"97","author":"Holick","year":"2012","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_28","unstructured":"Feldman, D. (2018). Chapter 57B\u2014The IOM\u2014Endocrine Society Controversy on Recommended Vitamin D Targets: In Support of the Endocrine Society Position. Vitamin D, Academic Press. [4th ed.]."},{"key":"ref_29","first-page":"69","article-title":"Statistics Corner: A Guide to Appropriate Use of Correlation Coefficient in Medical Research","volume":"24","author":"Mukaka","year":"2012","journal-title":"Malawi Med. J."},{"key":"ref_30","first-page":"227","article-title":"Explaining Odds Ratios","volume":"19","author":"Szumilas","year":"2010","journal-title":"J. Can. Acad. Child Adolesc. Psychiatry"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1609","DOI":"10.1002\/jbmr.387","article-title":"Vitamin D-Binding Protein Modifies the Vitamin D-Bone Mineral Density Relationship","volume":"26","author":"Powe","year":"2011","journal-title":"J. Bone Miner. Res."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"3356","DOI":"10.1210\/JC.2015-2066","article-title":"Free 25(OH)D and the Vitamin D Paradox in African Americans","volume":"100","author":"Aloia","year":"2015","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"105877","DOI":"10.1016\/j.jsbmb.2021.105877","article-title":"Reference Values for Free 25-Hydroxy-Vitamin D Based on Established Total 25-Hydroxy-Vitamin D Reference Values","volume":"210","author":"Zeng","year":"2021","journal-title":"J. Steroid Biochem. Mol. Biol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1631","DOI":"10.1210\/jc.2013-3874","article-title":"A Comparison of Measured and Calculated Free 25(OH) Vitamin D Levels in Clinical Populations","volume":"99","author":"Schwartz","year":"2014","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1016\/j.jsbmb.2018.03.005","article-title":"Reference Intervals for Measured and Calculated Free 25-Hydroxyvitamin D in Normal Pregnancy","volume":"181","author":"Tsuprykov","year":"2018","journal-title":"J. Steroid Biochem. Mol. Biol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"928","DOI":"10.1017\/S0007114518000491","article-title":"Vitamin D Deficiency and Insufficiency among US Adults: Prevalence, Predictors and Clinical Implications","volume":"119","author":"Liu","year":"2018","journal-title":"Br. J. Nutr."},{"key":"ref_37","first-page":"3906306","article-title":"Vitamin D Deficiency and Its Determinants in Adults: A Sample from Community-Based Settings in the United Arab Emirates","volume":"2017","author":"Eldeirawi","year":"2017","journal-title":"Int. J. Endocrinol."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"T\u00f8nnesen, R., Hovind, P.H., Jensen, L.T., and Schwarz, P. (2016). Determinants of Vitamin D Status in Young Adults: Influence of Lifestyle, Sociodemographic and Anthropometric Factors. BMC Public Health, 16.","DOI":"10.1186\/s12889-016-3042-9"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"605","DOI":"10.1016\/j.bone.2011.12.016","article-title":"Determinants of Vitamin D Status in a General Population of Danish Adults","volume":"50","author":"Thuesen","year":"2012","journal-title":"Bone"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"3121","DOI":"10.1007\/s00394-018-1856-1","article-title":"Determinants of Vitamin D Status in Physically Active Elderly in the Netherlands","volume":"58","author":"Balvers","year":"2019","journal-title":"Eur. J. Nutr."},{"key":"ref_41","unstructured":"(2021, July 28). Socioekonomske Zna\u010dilnosti Prebivalstva, Slovenija, 1 January 2020. Available online: https:\/\/www.stat.si\/StatWeb\/News\/Index\/9263."}],"updated-by":[{"DOI":"10.3390\/nu15092103","type":"correction","label":"Correction","source":"publisher","updated":{"date-parts":[[2022,12,16]],"date-time":"2022-12-16T00:00:00Z","timestamp":1671148800000}}],"container-title":["Nutrients"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6643\/14\/24\/5349\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,8,3]],"date-time":"2025-08-03T22:24:59Z","timestamp":1754259899000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6643\/14\/24\/5349"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,12,16]]},"references-count":41,"journal-issue":{"issue":"24","published-online":{"date-parts":[[2022,12]]}},"alternative-id":["nu14245349"],"URL":"https:\/\/doi.org\/10.3390\/nu14245349","relation":{"correction":[{"id-type":"doi","id":"10.3390\/nu15092103","asserted-by":"object"}]},"ISSN":["2072-6643"],"issn-type":[{"value":"2072-6643","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,12,16]]}}}