University of Oulu

Palaniswamy S, Hyppönen E, Williams DM, et al. Potential determinants of vitamin D in Finnish adults: a cross-sectional study from the Northern Finland birth cohort 1966. BMJ Open 2017;7:e013161. doi:10.1136/bmjopen-2016-013161

Potential determinants of vitamin D in Finnish adults : a cross-sectional study from the Northern Finland birth cohort 1966

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Author: Palaniswamy, Saranya1,2; Hyppönen, Elina3,4; Williams, Dylan M5;
Organizations: 1Biocenter Oulu, University of Oulu, Oulu, Finland
2Faculty of Medicine, Center for Life Course Health Research, University of Oulu, Oulu, Finland
3Centre for Population Health Research, School of Health Sciences and Sansom Institute, University of South Australia, South Australian Health and Medical Research Institute, Adelaide, Australia
4Population, Policy and Practice, Institute of Child Health, University College London, London, UK
5Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
6MRC and Unit of Primary Care, Oulu University Hospital, Oulu, Finland
7Department of Physiology, Institute of Biomedicine, University of Oulu, Oulu, Finland
8Department of Gastroenterology and Metabolism, Poznan University of Medical Sciences, Poznan, Poland
9CEU Cardenal Herrera University, Valencia, Spain
10Department of Epidemiology and Biostatistics, School of Public health, Imperial College London, London, UK
11MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College London, London, UK
12Department of Genomics of Complex Diseases, School of Public Health, Imperial College London, London, UK
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.1 MB)
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Language: English
Published: BMJ, 2017
Publish Date: 2017-05-19


Objective: Evidence from randomised controlled trials suggests that vitamin D may reduce multimorbidity, but very few studies have investigated specific determinants of vitamin D2 and D3 (two isoforms of 25-hydroxyvitamin D). The aim of the study was to investigate the determinants of vitamin D2 and D3 and to identify the risk factors associated with hypovitaminosis D.

Design: Cross-sectional study.

Setting: Northern Finland Birth Cohort 1966.

Participants: 2374 male and 2384 female participants with data on serum 25(OH)D₂ and 25(OH)D₃ concentrations measured at 31 years of age (1997), together with comprehensive measures of daylight, anthropometric, social, lifestyle and contraceptive cofactors.

Methods: We assessed a wide range of potential determinants prior to a nationwide fortification programme introduced in Finland. The determinants of 25(OH)D₂, 25(OH)D₃ and 25(OH)D concentrations were analysed by linear regression and risk factors for being in lower tertile of 25(OH)D concentration by ordinal logistic regression.

Results: At the time of sampling, 72% of the participants were vitamin D sufficient (≥50 nmol/L). Low sunlight exposure period (vs high) was associated positively with 25(OH)D₂ and negatively with 25(OH)D₃ concentrations. Use of oral contraceptives (vs nonusers) was associated with an increase of 0.17 nmol/L (95% CI 0.08 to 0.27) and 0.48 nmol/L (95% CI 0.41 to 0.56) in 25(OH)D₂ and 25(OH)D₃ concentrations. Sex, season, latitude, alcohol consumption and physical activity were the factors most strongly associated with 25(OH)D concentration. Risk factors for low vitamin D status were low sunlight exposure defined by time of sampling, residing in northern latitudes, obesity, higher waist circumference, low physical activity and unhealthy diet.

Conclusions: We demonstrate some differential associations of environmental and lifestyle factors with 25(OH)D₂ and 25(OH)D₃ raising important questions related to personalised healthcare. Future strategies could implement lifestyle modification and supplementation to improve vitamin D2 and D3 status, accounting for seasonal, lifestyle, metabolic and endocrine status.

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Series: BMJ open
ISSN: 2044-6055
ISSN-E: 2044-6055
ISSN-L: 2044-6055
Volume: 7
Issue: 3
Article number: e013161
DOI: 10.1136/bmjopen-2016-013161
Type of Publication: A1 Journal article – refereed
Field of Science: 3142 Public health care science, environmental and occupational health
Funding: This work was financially supported by the Academy of Finland (MRJ, grant number 24300796); Medical Research Council, UK (EH, grant number G0601653); Biocenter Oulu Doctoral Programme (SP); European Union’s Horizon 2020 research and innovation programme (MRJ, SS, DMW, grant number 633595) for the DynaHEALTH action.
EU Grant Number: (633595) DYNAHEALTH - Understanding the dynamic determinants of glucose homeostasis and social capability to promote Healthy and active aging
Copyright information: Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: