title: Validation and reproducibility of food frequency questionnaire for Korean genome epidemiologic study.
abstract: OBJECTIVE
  To evaluate validity and reliability of the food-frequency questionnaire (FFQ) developed for the Korean Genome Epidemiologic Study (KoGES).
  
  
  METHODS
  FFQ was administered twice at 1-year interval (first FFQ (FFQ1) at the beginning and second FFQ (FFQ2) at the end of the study) and diet records (DRs) were collected for 3 days during each of the four seasons from December 2002 to May 2004 for those who attended the health examination center. At the end of the study period, we collected the 12-day DRs of 124 participants. The nutrient intakes from the DRs were compared with both FFQ1 and FFQ2.
  
  
  RESULTS
  The intakes of energy and some nutrients estimated from FFQ1 and FFQ2 were different from those assessed by the DRs. Especially, the consumption of carbohydrates was higher in FFQ1 and FFQ2 than in the DRs. The de-attenuated, age, sex and energy intake adjusted correlation coefficients between the FFQ2 and the 12-day DRs in Korean population ranged between 0.23 (Vitamin A) and 0.64 (carbohydrate). The median for all nutrients was 0.39. The correlations were similar when we compared nutrient densities of both methods. Joint classification of calorie-adjusted nutrient intakes assessed by FFQ2 and 12-day DRs by quartile ranged from 25.8% (vitamin A) to 39.5% (carbohydrate, iron) for exact concordance. Except vitamin A, the proportion of subjects classified into distant quartile was less than 7% in all nutrients. The median of correlations between the two FFQs 1 year apart were 0.45 for all nutrient intakes and 0.39 for nutrient densities.
  
  
  CONCLUSIONS
  We conclude that the FFQ we have developed appears to be an acceptable tool for assessing the nutrient intakes in this population. Further studies for calibration of the FFQ collected from multicenters participating in the KoGES are needed.
  
  
  BACKGROUND
  This study was supported by the budget of the National Genome Research Institute, Korea National Institute of Health (2002-347-6111-221).
authors.affiliation: Center for Genomic Science, National Institute of Health, Center for Disease Control and Prevention, Seoul, Korea.
authors.forename: Y
authors.initials: Y
authors.lastname: Ahn
authors.forename: E
authors.initials: E
authors.lastname: Kwon
authors.forename: J E
authors.initials: JE
authors.lastname: Shim
authors.forename: M K
authors.initials: MK
authors.lastname: Park
authors.forename: Y
authors.initials: Y
authors.lastname: Joo
authors.forename: K
authors.initials: K
authors.lastname: Kimm
authors.forename: C
authors.initials: C
authors.lastname: Park
authors.forename: D H
authors.initials: DH
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D004032:Diet; D015930:Diet Records; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D002149:Energy Intake / Q000502:physiology*; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D007723:Korea; D008297:Male; D008875:Middle Aged; D008903:Minerals / Q000008:administration & dosage; D015203:Reproducibility of Results; D012621:Seasons; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires / Q000592:standards*; D014815:Vitamins / Q000008:administration & dosage
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D008903:Minerals; D014815:Vitamins