title: Reproducibility of the Online Food4Me Food-Frequency Questionnaire for Estimating Dietary Intakes across Europe.
abstract: Accurate dietary assessment is key to understanding nutrition-related outcomes and is essential for estimating dietary change in nutrition-based interventions.
  
  
  
  The objective of this study was to assess the pan-European reproducibility of the Food4Me food-frequency questionnaire (FFQ) in assessing the habitual diet of adults.
  
  
  
  Participants from the Food4Me study, a 6-mo, Internet-based, randomized controlled trial of personalized nutrition conducted in the United Kingdom, Ireland, Spain, Netherlands, Germany, Greece, and Poland, were included. Screening and baseline data (both collected before commencement of the intervention) were used in the present analyses, and participants were included only if they completed FFQs at screening and at baseline within a 1-mo timeframe before the commencement of the intervention. Sociodemographic (e.g., sex and country) and lifestyle [e.g., body mass index (BMI, in kg/m(2)) and physical activity] characteristics were collected. Linear regression, correlation coefficients, concordance (percentage) in quartile classification, and Bland-Altman plots for daily intakes were used to assess reproducibility.
  
  
  
  In total, 567 participants (59% female), with a mean ± SD age of 38.7 ± 13.4 y and BMI of 25.4 ± 4.8, completed both FFQs within 1 mo (mean ± SD: 19.2 ± 6.2 d). Exact plus adjacent classification of total energy intake in participants was highest in Ireland (94%) and lowest in Poland (81%). Spearman correlation coefficients (ρ) in total energy intake between FFQs ranged from 0.50 for obese participants to 0.68 and 0.60 in normal-weight and overweight participants, respectively. Bland-Altman plots showed a mean difference between FFQs of 210 kcal/d, with the agreement deteriorating as energy intakes increased. There was little variation in reproducibility of total energy intakes between sex and age groups.
  
  
  
  The online Food4Me FFQ was shown to be reproducible across 7 European countries when administered within a 1-mo period to a large number of participants. The results support the utility of the online Food4Me FFQ as a reproducible tool across multiple European populations. This trial was registered at clinicaltrials.gov as NCT01530139.
authors.affiliation: Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom;
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Marshall
authors.affiliation: Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom;
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Livingstone
authors.affiliation: Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom;
authors.forename: Carlos
authors.initials: C
authors.lastname: Celis-Morales
authors.affiliation: University College Dublin Institute of Food and Health, University College Dublin, Belfield, Dublin, Republic of Ireland;
authors.forename: Hannah
authors.initials: H
authors.lastname: Forster
authors.affiliation: Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, United Kingdom;
authors.forename: Rosalind
authors.initials: R
authors.lastname: Fallaize
authors.affiliation: University College Dublin Institute of Food and Health, University College Dublin, Belfield, Dublin, Republic of Ireland;
authors.forename: Clare B
authors.initials: CB
authors.lastname: O'Donovan
authors.affiliation: University College Dublin Institute of Food and Health, University College Dublin, Belfield, Dublin, Republic of Ireland;
authors.forename: Clara
authors.initials: C
authors.lastname: Woolhead
authors.affiliation: Department of Human Biology, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre, Maastricht, Netherlands;
authors.forename: Cyril Fm
authors.initials: CF
authors.lastname: Marsaux
authors.affiliation: Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, United Kingdom;
authors.forename: Anna L
authors.initials: AL
authors.lastname: Macready
authors.affiliation: Center for Nutrition Research, University of Navarra, Pamplona, Spain; Biomedical Research Center Network (CIBER) in Physiopathology of Obesity and Nutrition, Institute of Health Carlos III, Madrid, Spain;
authors.forename: Santiago
authors.initials: S
authors.lastname: Navas-Carretero
authors.affiliation: Center for Nutrition Research, University of Navarra, Pamplona, Spain; Biomedical Research Center Network (CIBER) in Physiopathology of Obesity and Nutrition, Institute of Health Carlos III, Madrid, Spain;
authors.forename: Rodrigo
authors.initials: R
authors.lastname: San-Cristobal
authors.affiliation: Research Center of Nutrition and Food Sciences (ZIEL), Biochemistry Unit, Technical University of Munich, Munich, Germany;
authors.forename: Silvia
authors.initials: S
authors.lastname: Kolossa
authors.affiliation: Department of Nutrition and Dietetics, Harokopio University, Athens, Greece;
authors.forename: Lydia
authors.initials: L
authors.lastname: Tsirigoti
authors.affiliation: Department of Nutrition and Dietetics, Harokopio University, Athens, Greece;
authors.forename: Christina P
authors.initials: CP
authors.lastname: Lambrinou
authors.affiliation: Department of Nutrition and Dietetics, Harokopio University, Athens, Greece;
authors.forename: George
authors.initials: G
authors.lastname: Moschonis
authors.affiliation: The National Food & Nutrition Institute (NFNI), Warsaw, Poland; and.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Godlewska
authors.affiliation: The National Food & Nutrition Institute (NFNI), Warsaw, Poland; and.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Surwiłło
authors.affiliation: Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway.
authors.forename: Christian A
authors.initials: CA
authors.lastname: Drevon
authors.affiliation: Department of Nutrition and Dietetics, Harokopio University, Athens, Greece;
authors.forename: Yannis
authors.initials: Y
authors.lastname: Manios
authors.affiliation: The National Food & Nutrition Institute (NFNI), Warsaw, Poland; and.
authors.forename: Iwona
authors.initials: I
authors.lastname: Traczyk
authors.affiliation: Center for Nutrition Research, University of Navarra, Pamplona, Spain; Biomedical Research Center Network (CIBER) in Physiopathology of Obesity and Nutrition, Institute of Health Carlos III, Madrid, Spain;
authors.forename: J Alfredo
authors.initials: JA
authors.lastname: Martínez
authors.affiliation: Department of Human Biology, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre, Maastricht, Netherlands;
authors.forename: Wim H
authors.initials: WH
authors.lastname: Saris
authors.affiliation: Research Center of Nutrition and Food Sciences (ZIEL), Biochemistry Unit, Technical University of Munich, Munich, Germany;
authors.forename: Hannelore
authors.initials: H
authors.lastname: Daniel
authors.affiliation: University College Dublin Institute of Food and Health, University College Dublin, Belfield, Dublin, Republic of Ireland;
authors.forename: Eileen R
authors.initials: ER
authors.lastname: Gibney
authors.affiliation: University College Dublin Institute of Food and Health, University College Dublin, Belfield, Dublin, Republic of Ireland;
authors.forename: Lorraine
authors.initials: L
authors.lastname: Brennan
authors.affiliation: University College Dublin Institute of Food and Health, University College Dublin, Belfield, Dublin, Republic of Ireland;
authors.forename: Marianne C
authors.initials: MC
authors.lastname: Walsh
authors.affiliation: Hugh Sinclair Unit of Human Nutrition and Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, United Kingdom;
authors.forename: Julie A
authors.initials: JA
authors.lastname: Lovegrove
authors.affiliation: University College Dublin Institute of Food and Health, University College Dublin, Belfield, Dublin, Republic of Ireland;
authors.forename: Mike
authors.initials: M
authors.lastname: Gibney
authors.affiliation: Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom; john.mathers@newcastle.ac.uk.
authors.forename: John C
authors.initials: JC
authors.lastname: Mathers
mesh_terms: D000328:Adult; D004032:Diet; D004034:Diet Surveys / Q000592:standards*; D002149:Energy Intake; D005060:Europe; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results
keywords: European; dietary intakes; food-frequency questionnaire; online; reproducibility