title: Bias in protein and potassium intake collected with 24-h recalls (EPIC-Soft) is rather comparable across European populations.
abstract: OBJECTIVE
  We investigated whether group-level bias of a 24-h recall estimate of protein and potassium intake, as compared to biomarkers, varied across European centers and whether this was influenced by characteristics of individuals or centers.
  
  
  METHODS
  The combined data from EFCOVAL and EPIC studies included 14 centers from 9 countries (n = 1,841). Dietary data were collected using a computerized 24-h recall (EPIC-Soft). Nitrogen and potassium in 24-h urine collections were used as reference method. Multilevel linear regression analysis was performed, including individual-level (e.g., BMI) and center-level (e.g., food pattern index) variables.
  
  
  RESULTS
  For protein intake, no between-center variation in bias was observed in men while it was 5.7% in women. For potassium intake, the between-center variation in bias was 8.9% in men and null in women. BMI was an important factor influencing the biases across centers (p < 0.01 in all analyses). In addition, mode of administration (p = 0.06 in women) and day of the week (p = 0.03 in men and p = 0.06 in women) may have influenced the bias in protein intake across centers. After inclusion of these individual variables, between-center variation in bias in protein intake disappeared for women, whereas for potassium, it increased slightly in men (to 9.5%). Center-level variables did not influence the results.
  
  
  CONCLUSIONS
  The results suggest that group-level bias in protein and potassium (for women) collected with 24-h recalls does not vary across centers and to a certain extent varies for potassium in men. BMI and study design aspects, rather than center-level characteristics, affected the biases across centers.
authors.affiliation: Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands. sandracrispim@gmail.com
authors.forename: Sandra P
authors.initials: SP
authors.lastname: Crispim
authors.forename: Anouk
authors.initials: A
authors.lastname: Geelen
authors.forename: Jeanne H M
authors.initials: JH
authors.lastname: de Vries
authors.forename: Heinz
authors.initials: H
authors.lastname: Freisling
authors.forename: Olga W
authors.initials: OW
authors.lastname: Souverein
authors.forename: Paul J M
authors.initials: PJ
authors.lastname: Hulshof
authors.forename: Marga C
authors.initials: MC
authors.lastname: Ocke
authors.forename: Hendriek
authors.initials: H
authors.lastname: Boshuizen
authors.forename: Lene F
authors.initials: LF
authors.lastname: Andersen
authors.forename: Jiri
authors.initials: J
authors.lastname: Ruprich
authors.forename: Willem
authors.initials: W
authors.lastname: De Keyzer
authors.forename: Willem
authors.initials: W
authors.lastname: De Keizer
authors.forename: Inge
authors.initials: I
authors.lastname: Huybrechts
authors.forename: Lionel
authors.initials: L
authors.lastname: Lafay
authors.forename: Maria S
authors.initials: MS
authors.lastname: de Magistris
authors.forename: Fulvio
authors.initials: F
authors.lastname: Ricceri
authors.forename: Rosario
authors.initials: R
authors.lastname: Tumino
authors.forename: Vittorio
authors.initials: V
authors.lastname: Krogh
authors.forename: H Bas
authors.initials: HB
authors.lastname: Bueno-de-Mesquita
authors.forename: Joline W J
authors.initials: JW
authors.lastname: Beulens
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Boutron-Ruault
authors.forename: Androniki
authors.initials: A
authors.lastname: Naska
authors.forename: Francesca L
authors.initials: FL
authors.lastname: Crowe
authors.forename: Heiner
authors.initials: H
authors.lastname: Boeing
authors.forename: Alison
authors.initials: A
authors.lastname: McTaggart
authors.forename: Rudolf
authors.initials: R
authors.lastname: Kaaks
authors.forename: Pieter
authors.initials: P
authors.lastname: Van't Veer
authors.forename: Nadia
authors.initials: N
authors.lastname: Slimani
mesh_terms: D000328:Adult; D000886:Anthropometry; D015415:Biomarkers / Q000652:urine; D002138:Calibration; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000652:urine; D002149:Energy Intake; D005060:Europe; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D011939:Mental Recall; D055361:Multilevel Analysis; D009749:Nutrition Surveys; D017419:Potassium, Dietary / Q000008:administration & dosage* / Q000652:urine; D011446:Prospective Studies; D012984:Software; D011795:Surveys and Questionnaires
chemical_list: D015415:Biomarkers; D004044:Dietary Proteins; D017419:Potassium, Dietary