ArticleEuropean journal of clinical nutrition2016
Cosinor modelling of seasonal variation in 25-hydroxyvitamin D concentrations in cardiovascular patients in Norway.
Article in European journal of clinical nutrition, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 29 papers.
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Who cites it
29 citing papers in PubMed.
- Seasonal fluctuations of cardiovascular risk markers in patients referred to coronary angiography.Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology · 2026Article
- Season-adjusted longitudinal changes in serum 25-hydroxyvitamin D during pegylated interferon add-on to ongoing tenofovir alafenamide therapy in chronic hepatitis B: a real-world cohort study.Frontiers in medicine · 2026Article
- Gaps in Vitamin D Intake and Status in Moroccan Women.Epidemiologia (Basel, Switzerland) · 2025Article
- Serum vitamin D, blood pressure and hypertension risk in the HUNT study using observational and Mendelian randomization approaches.Scientific reports · 2024Observational
- Associations of Serum Vitamin D With Dental Caries and Periodontitis: The HUNT Study.International dental journal · 2024Article
- Exploratory analyses on the effect of time since last meal on concentrations of amino acids, lipids, one-carbon metabolites, and vitamins in the Hordaland Health Study.European journal of nutrition · 2023Article
- Association of serum 25-hydroxyvitamin D with the incidence of 16 cancers, cancer mortality, and all-cause mortality among individuals with metabolic syndrome: a prospective cohort study.European journal of nutrition · 2023Article
- Vitamin D Status Over Time and Cognitive Function in Norwegian Older Adults: A Prospective Cohort of the HUNT Study.The journal of nutrition, health & aging · 2023Article
- Article
- Seasonality of Deaths Due to Heart Diseases among Cancer Patients.Medicina (Kaunas, Lithuania) · 2022Article
- Response to Analysis of serum 25-hydroxyvitamin D levels involves taking into account several confounding factors.European journal of clinical nutrition · 2022Article
- Analysis of serum 25-hydroxyvitamin D levels involves taking into account several confounding factors.European journal of clinical nutrition · 2022Article
- Measurement of Plasma 25-Hydroxyvitamin D Levels Requires Consideration of Ultraviolet Exposure From Sunlight.The oncologist · 2022Article
- Pre-infection 25-hydroxyvitamin D3 levels and association with severity of COVID-19 illness.PloS one · 2022Article
- Seasonal variation of serum 25-hydroxyvitamin D level in hemodialysis patients in the northernmost island of Japan.Clinical and experimental nephrology · 2021Observational
- Growth, body composition, and cardiovascular and nutritional risk of 5- to 10-y-old children consuming vegetarian, vegan, or omnivore diets.The American journal of clinical nutrition · 2021Article
- Power determination in vitamin D randomised control trials and characterising factors affecting it through a novel simulation-based tool.Scientific reports · 2021Article
- Global Dieting Trends and Seasonality: Social Big-Data Analysis May Be a Useful Tool.Nutrients · 2021Article
- Vitamin D status and risk of type 2 diabetes in the Norwegian HUNT cohort study: does family history or genetic predisposition modify the association?BMJ open diabetes research & care · 2021Article
- Lipid status association with 25-hydroxy vitamin D: Cross sectional study of end stage renal disease patients.Journal of medical biochemistry · 2020Article
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Authors and funding
10 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
BACKGROUND/
objectivesSeasonal variation may reduce the validity of 25-hydroxyvitamin D (25OHD) as a biomarker of vitamin D status. Here we aimed to identify potential determinants of seasonal variation in 25OHD concentrations and to evaluate cosinor modelling as a method to adjust single 25OHD measurements for seasonal variation. SUBJECTS/
methodsIn Caucasian cardiovascular patients (1999-2004), we measured 25OHD by liquid chromatography tandem mass spectrometry in 4116 baseline and 528 follow-up samples. To baseline values, we fitted a cosinor model for monthly concentrations of 25OHD. Using the model, we estimated each patient's adjusted annual 25OHD value. Further, we studied how covariates affected the annual mean 25OHD concentration and seasonal variation of the study cohort. To evaluate the model, we predicted follow-up measurements with and without covariates and compared accuracy with carrying forward baseline values and linear regression adjusting for season, common approaches in research and clinical practice, respectively.
resultsThe annual mean (59.6 nmol/l) was associated with participants' age, gender, smoking status, body mass, physical activity level, diabetes diagnosis, vitamin D supplement use and study site (adjusted models, P<0.05). Seasonal 25OHD variation was 15.8 nmol/l, and older age (>62 years) was associated with less variation (adjusted model, P=0.025). Prediction of follow-up measurements was more accurate with the cosinor model compared with the other approaches (P<0.05). Adding covariates to cosinor models did not improve prediction (P>0.05).
conclusionsWe find cosinor models suitable and flexible for analysing and adjusting for seasonal variation in 25OHD concentrations, which is influenced by age.
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