{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T16:47:24Z","timestamp":1783529244017,"version":"3.55.0"},"reference-count":45,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2025,12,11]],"date-time":"2025-12-11T00:00:00Z","timestamp":1765411200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Background\/Objectives: Vitamin D deficiency is recognized as a global public health concern due to its implications for bone health, immune regulation, and chronic disease risk. Despite its significance, comprehensive data on the prevalence of hypovitaminosis D in the Croatian population remain limited. This study aimed to determine the distribution of 25-hydroxyvitamin D (25-OH D) levels in a group of patients who underwent routine clinical examination, evaluate the prevalence of deficiency, and assess potential associations with demographic factors such as age and sex. Methods: This cross-sectional study included 829 individuals aged 19\u201385 years who underwent routine clinical testing at our institution. Serum 25-OH D concentrations were measured and classified as normal (\u226575 nmol\/L), deficient (&lt;75 nmol\/L, \u226550 nmol\/L), or severely deficient (&lt;50 nmol\/L). Data on age and sex were extracted, and statistical analyses included descriptive statistics, tests for normality (Kolmogorov\u2013Smirnov), comparisons (Mann\u2013Whitney U, Kruskal\u2013Wallis), and correlation testing (Spearman\u2019s rho). Significance was set at p &lt; 0.05. Results: The cohort consisted of 525 females (63.3%) and 304 males (36.7%), with a mean age of 49.2 \u00b1 15.8 years. The mean and median serum 25-OH D concentrations were 53.5 and 53.0 nmol\/L, respectively (IQR: 40.0\u201365.0). Severe deficiency (&lt;50 nmol\/L) was present in 43.7% of participants, while an additional 49.2% exhibited moderate deficiency, leaving only 7.1% with sufficient levels. No statistically significant differences in vitamin D levels were observed between sexes, nor was there a significant correlation between age and vitamin D concentration (p &gt; 0.05). Conclusions: Vitamin D deficiency is highly prevalent in the Croatian population, with more than 90% of individuals showing suboptimal serum levels. The absence of significant associations with age or sex suggests a widespread deficiency pattern, underscoring the need for nationwide preventive strategies, including dietary supplementation and public health education initiatives to improve vitamin D status.<\/jats:p>","DOI":"10.3390\/nu17243863","type":"journal-article","created":{"date-parts":[[2025,12,11]],"date-time":"2025-12-11T11:17:27Z","timestamp":1765451847000},"page":"3863","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Prevalence of Vitamin D Hypovitaminosis in Croatia: A Cross-Sectional Study Based on Routine Clinical Examinations"],"prefix":"10.3390","volume":"17","author":[{"given":"Jelena","family":"Kelemen","sequence":"first","affiliation":[{"name":"St. Catherine Specialty Hospital, 10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6522-891X","authenticated-orcid":false,"given":"Luka","family":"Buli\u0107","sequence":"additional","affiliation":[{"name":"St. Catherine Specialty Hospital, 10000 Zagreb, Croatia"},{"name":"School of Medicine, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8022-4095","authenticated-orcid":false,"given":"Petar","family":"Brlek","sequence":"additional","affiliation":[{"name":"St. Catherine Specialty Hospital, 10000 Zagreb, Croatia"},{"name":"School of Medicine, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia"},{"name":"Department of Molecular Biology, Faculty of Science, University of Zagreb, 10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1590-0514","authenticated-orcid":false,"given":"Renata","family":"Zadro","sequence":"additional","affiliation":[{"name":"St. Catherine Specialty Hospital, 10000 Zagreb, Croatia"},{"name":"Faculty of Pharmacy and Biochemistry, University of Zagreb, 10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jelena","family":"Pavlovi\u0107","sequence":"additional","affiliation":[{"name":"St. Catherine Specialty Hospital, 10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marin","family":"Vu\u010di\u0107","sequence":"additional","affiliation":[{"name":"St. Catherine Specialty Hospital, 10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eva","family":"Brenner","sequence":"additional","affiliation":[{"name":"St. Catherine Specialty Hospital, 10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5565-080X","authenticated-orcid":false,"given":"Dragan","family":"Primorac","sequence":"additional","affiliation":[{"name":"St. Catherine Specialty Hospital, 10000 Zagreb, Croatia"},{"name":"School of Medicine, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia"},{"name":"Faculty of Dental Medicine and Health, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia"},{"name":"Forensic Science Program, Department of Biochemistry & Molecular Biology, The Pennsylvania State University, State College, PA 16802, USA"},{"name":"The Henry C. Lee College of Criminal Justice and Forensic Sciences, University of New Haven, West Haven, CT 06516, USA"},{"name":"Sana Kliniken Oberfranken, 96450 Coburg, Germany"},{"name":"School of Medicine, University of Split, 21000 Split, Croatia"},{"name":"Medical School, University of Rijeka, 51000 Rijeka, Croatia"},{"name":"Medical School, University of Mostar, 88000 Mostar, Bosnia and Herzegovina"},{"name":"National Forensic Sciences University, Gandhinagar 382007, India"},{"name":"School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1016\/j.chembiol.2013.12.016","article-title":"Vitamin D metabolism, mechanism of action, and clinical applications","volume":"21","author":"Bikle","year":"2014","journal-title":"Chem. 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