ArticleEndocrine2015
Seasonal variations in serum 25-hydroxy vitamin D levels in a Swedish cohort.
Article in Endocrine, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 114 papers, 3 of them syntheses that pooled it.
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Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
114 citing papers in PubMed, 3 syntheses or guidelines pooled it.
- Vitamin D status and supplementation in Antarctica: a systematic review and meta- analysis.International journal of circumpolar health · 2021Pooled it
- Pooled it
- Guideline
- Vitamin D Supplementation and Testosterone Levels in Breast Cancer Survivors.International journal of molecular sciences · 2025Trial
- Serum 25-hydroxyvitamin D response to vitamin D supplementation using different lipid delivery systems in middle-aged and older adults: a randomised controlled trial.The British journal of nutrition · 2023Trial
- 25-Hydroxyvitamin D in Cancer Patients Admitted to Palliative Care: A Post-Hoc Analysis of the Swedish Trial 'Palliative-D'.Nutrients · 2022Trial
- Trial
- Vitamin DJournal of cachexia, sarcopenia and muscle · 2021Trial
- Vitamin D Supplementation during Winter: Effects on Stress Resilience in a Randomized Control Trial.Nutrients · 2020Trial
- Safety and tolerability of 6-month supplementation with a vitamin D, calcium and leucine-enriched whey protein medical nutrition drink in sarcopenic older adults.Aging clinical and experimental research · 2020Trial
- Winter Exercise Reduces Allergic Airway Inflammation: A Randomized Controlled Study.International journal of environmental research and public health · 2019Trial
- 25-hydroxyvitamin D serum levels in patients with high risk resected melanoma treated in an adjuvant bevacizumab trial.British journal of cancer · 2018Trial
- Vitamin D and vitamin B12 deficiencies are common in patients with midgut carcinoid (SI-NET).European journal of clinical nutrition · 2016Trial
- Letter to the editor: "Is vitamin D the missing link in recurrent urinary tract infections in children? A prospective study".World journal of urology · 2026Article
- Impact of vitamin D deficiency on 6-month culture conversion in nontuberculous mycobacterial pulmonary disease.Scientific reports · 2026Article
- Vitamin D in Cardiovascular Medicine: From Molecular Mechanisms to Clinical Translation.Nutrients · 2026Review
- Disrupted Vitamin D Signaling and Metabolism in Neurodevelopmental and Neurodegenerative Disorders.ASN neuro · 2026Review
- Comparing mortality burdens attributable to ambient temperature and seasonal variation across major causes of death in Spain.Environmental epidemiology (Philadelphia, Pa.) · 2025Article
- High Prevalence of Vitamin D Deficiency in Patients Undergoing Total Shoulder or Elbow Arthroplasty.Nutrients · 2025Article
- Prolonged Effects of COVID-19-Related Behavioral Restrictions on Neonatal Bone Metabolism: A Retrospective Study.Cureus · 2025Article
54 more citing papers are in PubMed but not listed here.
Corrections and comments
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Authors and funding
5 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
To study seasonal inter-individual and intra-individual variations in serum 25-hydroxy vitamin D (25(OH)D) and to explore parameters associated with 25(OH)D in a healthy Swedish adult population. 540 blood donors (60 % men; mean age 41 ± 13 years) and 75 thrombocyte donors (92 % men, aged 46 ± 11 years) were included. Serum was collected during 12 months and analyzed for 25(OH)D and parathyroid hormone (S-iPTH). The blood donors answered questionnaires concerning vitamin D supplements, smoking, physical activity, sunbed use and sun holidays. Repeated serum samples were collected from the thrombocyte donors to study the intra-individual variations in S-25(OH)D. S-25(OH)D varied greatly over the year correlating with the intensity of the UV-B irradiation (r S = 0.326; p < 0.001). During January-March, a S-25(OH)D level below the thresholds of 50 and 75 nmol/L was observed in 58 and 88 %, respectively, and during July-September in 11 and 50 % (p < 0.001). S-25(OH)D was negatively correlated with body mass index and S-iPTH, but was significantly higher in holiday makers in sunny destinations, sunbed users, non-smokers, and in the physically active. The intra-individual analyses showed a mean increase in S-25(OH)D by 8 nmol/L/month between April and August. Approximately 75 % had serum 25(OH)D values <75 nmol/L during 75 % of the year and 50 % had serum 25(OH)D <50 nmol/L during 50 % of the year. Serum 25(OH)D was strongly associated with parameters related to sun exposure, but only weakly with intake of vitamin D supplements.
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