title: Reproducibility and validity of a self-administered food frequency questionnaire used in the JACC study.
abstract: BACKGROUND
  A self-administered questionnaire on dietary habits used in the JACC Study contained a 40-item food frequency questionnaire (FFQ). Although more than 110 thousand subjects enrolled in JACC Study and responded to the FFQ, no validation study has been conducted to date.
  
  
  METHODS
  Eighty-five volunteers among the cohort members completed 2 FFQs (FFQs 1&2) and 12-day weighed dietary records (WDR). The interval between the two FFQs was one year. During the one year, the subjects carried out a 3-consecutive-day WDR in each season. We tested the reproducibility by using two FFQs. Also, we tested the validity of the FFQ by using the 12-day WDR as a gold standard.
  
  
  RESULTS
  The intake frequencies of the 2 FFQs often agreed, showing the Spearman correlation coefficients ranging from 0.42 (edible wild plants) to 0.86 (coffee). The Spearman correlation coefficients of the energy and nutrient intakes from FFQ2, and that of the 12-day WDR were 0.20(energy) to 0.46 (animal protein, potassium). After adjusting the energy intake, the correlation coefficients showed 0.21(fish fat) to 0.51(animal fat). When classifying the FFQ2 and WDR by quartiles and examining the degree of agreement between the two methods, we obtained its median 30%.
  
  
  CONCLUSIONS
  The FFQ is suitable to deal with a large group of subjects. However, since the energy and the amount of nutrient intake from this FFQ can not show the overall dietary intake situation, the subjects' dietary intake should be assessed by categories.
authors.affiliation: Department of Nutrition and Food Sciences, Faculty of Human Environmental Sciences, Mukogawa Women's University, Japan. chigusa@cc.nara-wu.ac.jp
authors.forename: Chigusa
authors.initials: C
authors.lastname: Date
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Fukui
authors.forename: Akio
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Kenji
authors.initials: K
authors.lastname: Wakai
authors.forename: Azusa
authors.initials: A
authors.lastname: Ozeki
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Motohashi
authors.forename: Chieko
authors.initials: C
authors.lastname: Adachi
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Okamoto
authors.forename: Michiko
authors.initials: M
authors.lastname: Kurosawa
authors.forename: Yuko
authors.initials: Y
authors.lastname: Tokudome
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kurisu
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Kotaro
authors.initials: K
authors.lastname: Ozasa
authors.forename: Shuichi
authors.initials: S
authors.lastname: Nakagawa
authors.forename: Noritaka
authors.initials: N
authors.lastname: Tokui
authors.forename: Takesumi
authors.initials: T
authors.lastname: Yoshimura
authors.forename: Akiko
authors.initials: A
authors.lastname: Tamakoshi
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D015930:Diet Records; D004034:Diet Surveys; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008019:Life Style; D008297:Male; D009369:Neoplasms / Q000453:epidemiology*; D015203:Reproducibility of Results; D012307:Risk Factors; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires / Q000592:standards*