Evidence map›Paper›PMID 41978218›Full record

ArticleNutrients2026

Ten-Year Trends in Serum 25-Hydroxyvitamin D in Slovenia (2014-2023): Laboratory-Based Data from Tested Individuals and COVID-19-Period Changes.

Joško Osredkar, Darko Siuka, Aleš Jerin, Borut Štabuc, Uroš Godnov

Abstract read
In one paragraph

Article in Nutrients, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

What it found

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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

5 authors.

Joško OsredkarInstitute of Clinical Chemistry and Biochemistry, University Medical Centre Ljubljana, Zaloška Cesta 2, 1000 Ljubljana, Slovenia.ORCID 0000-0002-1839-2415
Darko SiukaDepartment of Gastroenterology, University Medical Centre Ljubljana, Zaloška Cesta 2, 1000 Ljubljana, Slovenia.
Aleš JerinInstitute of Clinical Chemistry and Biochemistry, University Medical Centre Ljubljana, Zaloška Cesta 2, 1000 Ljubljana, Slovenia.ORCID 0000-0002-6748-7082
Borut ŠtabucDepartment of Gastroenterology, University Medical Centre Ljubljana, Zaloška Cesta 2, 1000 Ljubljana, Slovenia.
Uroš GodnovFaculty of Mathematics, Natural Science and Information Technologies, University of Primorska, Glagoljaška Ulica 8, 6000 Koper, Slovenia.ORCID 0000-0003-4447-3435

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundVitamin D status is influenced by season, age, and public health messaging. The COVID-19 pandemic was accompanied by heightened interest in vitamin D, but long-term national data from Central/Eastern Europe remain limited. We aimed to characterize 10-year trends, seasonal variation, and demographic determinants of serum 25-hydroxyvitamin D [25(OH)D] in Slovenia, with particular focus on changes during the COVID-19 period.

methodsWe performed a retrospective cross-sectional analysis of all serum 25(OH)D measurements performed at the Slovenian national reference laboratory between January 2014 and December 2023. The core analytic cohort included 106,875 patients with valid 25(OH)D results, aged 0-100 years. Vitamin D status was classified as deficient (<30 nmol/L), insufficient (30-50 nmol/L), adequate (50-75 nmol/L), and optimal (>75 nmol/L). Temporal trends, seasonal patterns, and age- and sex-specific differences were assessed using non-parametric tests and Kendall's τ.

resultsMean 25(OH)D concentration over the study period was 61.9 ± 34.2 nmol/L; 16.0% of patients were deficient and 22.8% insufficient. Annual mean 25(OH)D increased from 57.0 nmol/L in 2014 to 67.2 nmol/L in 2023, with a significant upward temporal trend and a 14.6% higher mean level during 2020-2023 compared with 2014-2019. Seasonal variation was pronounced (≈20% higher summer-autumn vs. winter-spring), and vitamin D status declined progressively with age, with the highest deficiency prevalence in patients ≥ 70 years. Females had slightly higher 25(OH)D than males, although absolute differences were small.

conclusionsThis laboratory-based analysis of tested patients showed higher 25(OH)D concentrations during and after the COVID-19 period, superimposed on persistent seasonal and age-related gradients. These observations identify older adults and winter testing periods as important contexts for vitamin D optimization, but they should be interpreted as descriptive trends among tested individuals rather than as evidence of causal pandemic effects or population-wide prevalence changes.

Indexed as

COVID-19Vitamin DVitamin D DeficiencyAdolescentAdultAgedAged, 80 and overChildChild, PreschoolCross-Sectional StudiesFemaleHumansInfantInfant, NewbornMaleMiddle Aged25-hydroxyvitamin DVitamin D25-hydroxyvitamin Dage factorsCOVID-19 pandemicdeficiencyseasonal variation

Identifiers

PMID41978218
PMCPMC13074350

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.