title: Application of dried blood spots to determine vitamin D status in a large nutritional study with unsupervised sampling: the Food4Me project.
abstract: An efficient and robust method to measure vitamin D (25-hydroxy vitamin D3 (25(OH)D3) and 25-hydroxy vitamin D2 in dried blood spots (DBS) has been developed and applied in the pan-European multi-centre, internet-based, personalised nutrition intervention study Food4Me. The method includes calibration with blood containing endogenous 25(OH)D3, spotted as DBS and corrected for haematocrit content. The methodology was validated following international standards. The performance characteristics did not reach those of the current gold standard liquid chromatography-MS/MS in plasma for all parameters, but were found to be very suitable for status-level determination under field conditions. DBS sample quality was very high, and 3778 measurements of 25(OH)D3 were obtained from 1465 participants. The study centre and the season within the study centre were very good predictors of 25(OH)D3 levels (P<0·001 for each case). Seasonal effects were modelled by fitting a sine function with a minimum 25(OH)D3 level on 20 January and a maximum on 21 July. The seasonal amplitude varied from centre to centre. The largest difference between winter and summer levels was found in Germany and the smallest in Poland. The model was cross-validated to determine the consistency of the predictions and the performance of the DBS method. The Pearson's correlation between the measured values and the predicted values was r 0·65, and the sd of their differences was 21·2 nmol/l. This includes the analytical variation and the biological variation within subjects. Overall, DBS obtained by unsupervised sampling of the participants at home was a viable methodology for obtaining vitamin D status information in a large nutritional study.
authors.affiliation: 1DSM Nutritional Products,Analytical Research Centre and Human Nutrition & Health,4002 Basel,Switzerland.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hoeller
authors.affiliation: 1DSM Nutritional Products,Analytical Research Centre and Human Nutrition & Health,4002 Basel,Switzerland.
authors.forename: Manuela
authors.initials: M
authors.lastname: Baur
authors.affiliation: 1DSM Nutritional Products,Analytical Research Centre and Human Nutrition & Health,4002 Basel,Switzerland.
authors.forename: Franz F
authors.initials: FF
authors.lastname: Roos
authors.affiliation: 2UCD Institute of Food and Health,University College Dublin,Belfield,Dublin 4,Republic of Ireland.
authors.forename: Lorraine
authors.initials: L
authors.lastname: Brennan
authors.affiliation: 3ZIEL Research Center of Nutrition and Food Sciences,Biochemistry Unit,Technische Universität München,85435 Freising,Germany.
authors.forename: Hannelore
authors.initials: H
authors.lastname: Daniel
authors.affiliation: 4Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research,University of Reading,Reading RG6 6AP,UK.
authors.forename: Rosalind
authors.initials: R
authors.lastname: Fallaize
authors.affiliation: 2UCD Institute of Food and Health,University College Dublin,Belfield,Dublin 4,Republic of Ireland.
authors.forename: Hannah
authors.initials: H
authors.lastname: Forster
authors.affiliation: 2UCD Institute of Food and Health,University College Dublin,Belfield,Dublin 4,Republic of Ireland.
authors.forename: Eileen R
authors.initials: ER
authors.lastname: Gibney
authors.affiliation: 2UCD Institute of Food and Health,University College Dublin,Belfield,Dublin 4,Republic of Ireland.
authors.forename: Mike
authors.initials: M
authors.lastname: Gibney
authors.affiliation: 5National Food & Nutrition Institute,Warsaw 02903,Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Godlewska
authors.affiliation: 3ZIEL Research Center of Nutrition and Food Sciences,Biochemistry Unit,Technische Universität München,85435 Freising,Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Hartwig
authors.affiliation: 3ZIEL Research Center of Nutrition and Food Sciences,Biochemistry Unit,Technische Universität München,85435 Freising,Germany.
authors.forename: Silvia
authors.initials: S
authors.lastname: Kolossa
authors.affiliation: 6Department of Nutrition and Dietetics,Harokopio University,Kallithea 17671,Athens,Greece.
authors.forename: Christina P
authors.initials: CP
authors.lastname: Lambrinou
authors.affiliation: 7Human Nutrition Research Centre,Institute of Cellular Medicine,Newcastle University,Newcastle Upon Tyne NE1 7RU,UK.
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Livingstone
authors.affiliation: 4Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research,University of Reading,Reading RG6 6AP,UK.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Lovegrove
authors.affiliation: 4Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research,University of Reading,Reading RG6 6AP,UK.
authors.forename: Anna L
authors.initials: AL
authors.lastname: Macready
authors.affiliation: 6Department of Nutrition and Dietetics,Harokopio University,Kallithea 17671,Athens,Greece.
authors.forename: Yannis
authors.initials: Y
authors.lastname: Manios
authors.affiliation: 8Department of Human Biology,NUTRIM School of Nutrition and Translational Research in Metabolism,Maastricht University Medical Centre,6229 HX Maastricht,The Netherlands.
authors.forename: Cyril F M
authors.initials: CF
authors.lastname: Marsaux
authors.affiliation: 9Department of Nutrition, Food Science and Physiology,University of Navarra,31008 Pamplona,Spain.
authors.forename: J Alfredo
authors.initials: JA
authors.lastname: Martinez
authors.affiliation: 7Human Nutrition Research Centre,Institute of Cellular Medicine,Newcastle University,Newcastle Upon Tyne NE1 7RU,UK.
authors.forename: Carlos
authors.initials: C
authors.lastname: Celis-Morales
authors.affiliation: 6Department of Nutrition and Dietetics,Harokopio University,Kallithea 17671,Athens,Greece.
authors.forename: George
authors.initials: G
authors.lastname: Moschonis
authors.affiliation: 9Department of Nutrition, Food Science and Physiology,University of Navarra,31008 Pamplona,Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Navas-Carretero
authors.affiliation: 2UCD Institute of Food and Health,University College Dublin,Belfield,Dublin 4,Republic of Ireland.
authors.forename: Clare B
authors.initials: CB
authors.lastname: O'Donovan
authors.affiliation: 9Department of Nutrition, Food Science and Physiology,University of Navarra,31008 Pamplona,Spain.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: San-Cristobal
authors.affiliation: 8Department of Human Biology,NUTRIM School of Nutrition and Translational Research in Metabolism,Maastricht University Medical Centre,6229 HX Maastricht,The Netherlands.
authors.forename: Wim H M
authors.initials: WH
authors.lastname: Saris
authors.affiliation: 5National Food & Nutrition Institute,Warsaw 02903,Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Surwiłło
authors.affiliation: 5National Food & Nutrition Institute,Warsaw 02903,Poland.
authors.forename: Iwona
authors.initials: I
authors.lastname: Traczyk
authors.affiliation: 6Department of Nutrition and Dietetics,Harokopio University,Kallithea 17671,Athens,Greece.
authors.forename: Lydia
authors.initials: L
authors.lastname: Tsirigoti
authors.affiliation: 2UCD Institute of Food and Health,University College Dublin,Belfield,Dublin 4,Republic of Ireland.
authors.forename: Marianne C
authors.initials: MC
authors.lastname: Walsh
authors.affiliation: 2UCD Institute of Food and Health,University College Dublin,Belfield,Dublin 4,Republic of Ireland.
authors.forename: Clara
authors.initials: C
authors.lastname: Woolhead
authors.affiliation: 7Human Nutrition Research Centre,Institute of Cellular Medicine,Newcastle University,Newcastle Upon Tyne NE1 7RU,UK.
authors.forename: John C
authors.initials: JC
authors.lastname: Mathers
authors.affiliation: 1DSM Nutritional Products,Analytical Research Centre and Human Nutrition & Health,4002 Basel,Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Weber
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000097:blood; D000293:Adolescent; D000328:Adult; D000368:Aged; D002112:Calcifediol / Q000097:blood; D002138:Calibration; D003890:Desiccation; D004035:Diet Therapy / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015596:Nutrition Assessment; D009752:Nutritional Status; D010209:Paper; D011933:Reagent Kits, Diagnostic; D012016:Reference Values; D019114:Remote Consultation / Q000379:methods; D015203:Reproducibility of Results; D012621:Seasons; D012680:Sensitivity and Specificity; D014808:Vitamin D Deficiency / Q000097:blood*
chemical_list: D011933:Reagent Kits, Diagnostic; D015652:25-Hydroxyvitamin D 2; D002112:Calcifediol
keywords: 25(OH)D2
                  25-Hydroxy vitamin D2; 25(OH)D3
                  25-hydroxy vitamin D3; Analytical methods; DBS dried blood spots; Dried blood spot sampling; LOD limit of detection; LOQ limit of quantitation; MeOH methanol; Nutrition intervention study Food4Me; RT room temperature; Vitamin D status