title: Relative validity of the pre-coded food diary used in the Danish National Survey of Diet and Physical Activity.
abstract: OBJECTIVE
  To determine the relative validity of the pre-coded food diary applied in the Danish National Survey of Dietary Habits and Physical Activity.
  
  
  METHODS
  A cross-over study among seventy-two adults (aged 20 to 69 years) recording diet by means of a pre-coded food diary over 4 d and a 4 d weighed food record. Intakes of foods and drinks were estimated, and nutrient intakes were calculated. Means and medians of intake were compared, and cross-classification of individuals according to intake was performed. To assess agreement between the two methods, Pearson and Spearman's correlation coefficients and weighted kappa coefficients were calculated.
  
  
  METHODS
  Validation study of the pre-coded food diary against a 4 d weighed food record.
  
  
  METHODS
  Seventy-two volunteer, healthy free-living adults (thirty-five males, thirty-seven females).
  
  
  RESULTS
  Intakes of cereals and vegetables were higher, and intakes of fruit, coffee and tea were lower, in the weighed food record compared with the food diary. Intakes of nutrients were grossly the same in the two methods, except for protein, where a higher intake was recorded in the weighed record. In general, moderate agreement between the two methods was found.
  
  
  CONCLUSIONS
  Participants were classified moderately correct according to food and nutrient intakes assessed in the pre-coded food diary; however values of absolute food intakes should be used and interpreted with caution. Improvement of the methods to estimate portion size may increase the accuracy of the dietary intake estimates.
authors.affiliation: Division of Nutrition, National Food Institute, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark. vkkn@food.dtu.dk
authors.forename: Vibeke K
authors.initials: VK
authors.lastname: Knudsen
authors.forename: Maj-Britt
authors.initials: MB
authors.lastname: Gille
authors.forename: Trine H
authors.initials: TH
authors.lastname: Nielsen
authors.forename: Tue
authors.initials: T
authors.lastname: Christensen
authors.forename: Sisse
authors.initials: S
authors.lastname: Fagt
authors.forename: Anja
authors.initials: A
authors.lastname: Biltoft-Jensen
mesh_terms: D000328:Adult; D000368:Aged; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D003069:Coffee; D018592:Cross-Over Studies; D003718:Denmark; D004032:Diet; D015930:Diet Records; D004034:Diet Surveys; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D005638:Fruit; D006801:Humans; D008297:Male; D018977:Micronutrients / Q000008:administration & dosage; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D011446:Prospective Studies; D012189:Retrospective Studies; D014675:Vegetables; D055815:Young Adult
chemical_list: D003069:Coffee; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D018977:Micronutrients