Journals / Journal of Experimental and Clinical Medicine / 2026 / Volume: 43 Issue: 3

Hospital-based distribution of serum 25-hydroxyvitamin D levels by age, sex, and season: A retrospective cross-sectional study of 12,484 adult outpatients

Geniş Bir Hasta Popülasyonunda D Vitamini Düzeylerinin Yaş, Cinsiyet ve Mevsimsel Dağılımının Değerlendirilmesi

Fikriye Esra Gürses Ulubay(SAMSUN EĞİTİM VE ARAŞTIRMA HASTANESİ)0000-0001-5452-8052
Ayşegül Atmaca(ONDOKUZ MAYIS UNIVERSITY)0000-0001-6326-6365
Pages
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Publication Date
2026-09-30
DOI
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AI Summary & Key Takeaways

AI Insight
⚡ TL;DR(Too Long; Didn't Read)

Overall, 12,484 unique patients were included; 76.7% were women.

📌 3 Key Takeaways

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Objective & Hypothesis:This retrospective cross-sectional study described serum 25-hydroxyvitamin D [25(OH)D] levels according to age, sex, and season in a hospital-based, test-selected cohort of adult outpatients.
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Key Findings & Data:Adults tested for 25(OH)D at Ondokuz Mayıs University Faculty of Medicine Hospital during 2022 were included; for repeated measurements, only the first result was analyzed.
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Conclusion & Impact:Overall, 12,484 unique patients were included; 76.7% were women.
🔬Design:Research Article
📍Scope:2022 Verileri
⚙️Variables:Vitamin D · 25-hydroxyvitamin D · Age factors

Abstract

This retrospective cross-sectional study described serum 25-hydroxyvitamin D [25(OH)D] levels according to age, sex, and season in a hospital-based, test-selected cohort of adult outpatients. Adults tested for 25(OH)D at Ondokuz Mayıs University Faculty of Medicine Hospital during 2022 were included; for repeated measurements, only the first result was analyzed. Serum 25(OH)D was categorized as deficiency (<10 ng/mL), insufficiency (10–20 ng/mL), sufficient/study-defined target range (20–80 ng/mL), and elevated (≥80 ng/mL). Multivariable logistic regression assessed factors associated with suboptimal status (<20 ng/mL). Overall, 12,484 unique patients were included; 76.7% were women. Median 25(OH)D was 19.41 ng/mL (IQR, 10.95–28.47). Deficiency occurred in 22.1%, insufficiency in 29.6%, sufficient/study-defined target levels in 47.9%, and elevated levels in 0.5%. Median levels were similar in women and men (19.36 vs. 19.50 ng/mL; p=0.058) but differed by age group and season (both p<0.001). Compared with patients aged <65 years, the odds of suboptimal status were lower in those aged 65–74 years (OR, 0.63; 95% CI, 0.57–0.70) and ≥75 years (OR, 0.67; 95% CI, 0.57–0.78). Compared with summer, the odds were higher in spring (OR, 1.82), autumn (OR, 1.42), and winter (OR, 2.28; all p<0.001). Sex was not independently associated with suboptimal status. Serum 25(OH)D levels below 20 ng/mL were common among tested outpatients, with clear seasonal variation. Findings should not be generalized to the broader population because supplementation status, testing indication, and other potential confounders were unavailable.

Özet

Amaç: D vitamini, kemik sağlığı ve kalsiyum homeostazında kritik rol oynamakla birlikte birçok organ sistemi üzerinde de etkileri vardır. Takviye kullanımının yaygın olmasına rağmen D vitamini eksikliği dünya genelinde halen yaygındır. Bu çalışmanın amacı, geniş bir hasta popülasyonunda serum 25-hidroksivitamin D [25(OH)D] düzeylerinin yaş, cinsiyet ve mevsimlere göre dağılımını değerlendirmektir. Yöntemler: Bu retrospektif çalışmaya, Ocak–Aralık 2022 tarihleri arasında Ondokuz Mayıs Üniversitesi Tıp Fakültesi Hastanesi’ne başvuran ve serum 25(OH)D düzeyleri ölçülen 18 yaş ve üzeri 12.484 hasta dahil edildi. Hastalar, D vitamini düzeylerine göre (eksiklik 80 ng/mL), yaş grubuna (<65, 65–74, ≥75 yıl), cinsiyetine ve ölçüm mevsimine göre sınıflandırıldı. Serum 25(OH)D düzeyleri HPLC yöntemiyle analiz edildi. İstatistiksel analizlerde parametrik olmayan testler kullanıldı ve p <0,05 anlamlı kabul edildi. Bulgular: Katılımcıların %76,7’si kadın, %23,3’ü erkekti. Medyan serum 25(OH)D düzeyleri cinsiyetler arasında anlamlı farklılık göstermedi (p = 0,058). Hastaların %22,1’inde eksiklik, %29,6’sında yetersizlik, %47,9’unda optimal düzey, %0,5’inde ise hipervitaminoz saptandı. Mevsimsel analizde en düşük medyan düzeyler kışın (16,16 µg/mL), en yüksek düzeyler yazın (22,84 µg/mL) görüldü (p <0,001). Yaş gruplarına göre yapılan incelemede, <65 yaş grubunda D vitamini düzeyleri ileri yaş gruplarına kıyasla anlamlı derecede düşük bulundu (p <0,001). Sonuç: Hastaların yarısından azında optimal D vitamini düzeyi mevcuttu. D vitamini durumunun cinsiyete göre farklılık göstermediği, ancak mevsim ve yaşla ilişkili olduğu; kış aylarında ve genç yaş grubunda daha düşük olduğu belirlendi. Bu bulgular, D vitamini eksikliği konusunda farkındalığın artırılması gerektiğini vurgulamakta ve takviye ile yaşam tarzı düzenlemelerini içeren halk sağlığı stratejilerini desteklemektedir.

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Cite This Article

Ulubay, F. E. G., Atmaca, A. (2026). Hospital-based distribution of serum 25-hydroxyvitamin D levels by age, sex, and season: A retrospective cross-sectional study of 12,484 adult outpatients. Journal of Experimental and Clinical Medicine, Volume: 43 Issue: 3. https://ajindex.com/articles/1422490

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