title: Reproducibility and validity of the food frequency questionnaire for estimating habitual dietary intake in children and adolescents.
abstract: BACKGROUND
  A previous study reported the development a 75-item food frequency questionnaire for Japanese children (CFFQ). The first aim was to examine the reproducibility and validity of the CFFQ in order to assess dietary intake among two groups; 3-11 year old children (YC group) and 12-16 year old children (AD group). The second aim was to use the CFFQ and the FFQ for adults (AFFQ), and to determine which was better suited for assessing the intake of children in each group.
  
  
  METHODS
  A total of the 103 children participated in this study. The interval between the first CFFQ and AFFQ and the second CFFQ and AFFQ was one month. Four weighted dietary records (WDRs) were conducted once a week. Pearson's correlation coefficients between the first and second FFQs were calculated to test the reproducibility of each FFQ. Pearson's correlation coefficients between WDRs and the second FFQ were calculated for the unadjusted value and sex-, age-, and energy-adjusted values to determine the validity of each FFQ.
  
  
  RESULTS
  The final number of subjects participating in the analysis was 89. The median correlation coefficients between the first and second CFFQs and AFFQs were 0.76 and 0.73, respectively. There was some over/underestimation of nutrients in the CFFQ of the YC group and in the AFFQ of the AD group. The medians of the sex-, age-, and energy-adjusted correlation coefficients were not different between the YC and AD groups for each FFQ. The correlation coefficient in sex-, age-, and energy-adjusted value revealed that the largest number of subject with high (0.50 or more) value was obtained by the CFFQ in the YC group.
  
  
  CONCLUSIONS
  This study indicated that the CFFQ might be a useful tool for assessing habitual dietary intake of children in the YC group. Although the CFFQ agreed moderately with habitual intake, it was found to underestimate intake in theAD group. However, for the AFFQ, the ability to rank habitual intake was low. Therefore, it is necessary to develop a new FFQ or modify an existing FFQ to accurately assess the habitual diet of children in the AD group.
authors.affiliation: Department of Food and Nutritional Sciences, School of Natural Science and Ecological Awareness, Graduate School of Humanities and Sciences, Nara Women's University, Kitauoya-nishimachi, Nara, 630-8506, Japan. yataka@giga.ocn.ne.jp
authors.forename: Tomomi
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Miharu
authors.initials: M
authors.lastname: Kamimura
authors.forename: Shino
authors.initials: S
authors.lastname: Imai
authors.forename: Chihiro
authors.initials: C
authors.lastname: Toji
authors.forename: Naoko
authors.initials: N
authors.lastname: Okamoto
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Fukui
authors.forename: Chigusa
authors.initials: C
authors.lastname: Date
mesh_terms: D000293:Adolescent; D044466:Asian People; D002648:Child; D002675:Child, Preschool; D015930:Diet Records; D004034:Diet Surveys; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D005502:Food; D006801:Humans; D007564:Japan; D008297:Male; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires