title: Validity of a self-administered food frequency questionnaire for middle-aged urban cancer screenees: comparison with 4-day weighed dietary records.
abstract: BACKGROUND
  The validity of estimates of dietary intake calculated using a food frequency questionnaire (FFQ) depends on the specific population. The 138-item FFQ used in the 5-year follow-up survey for the Japan Public Health Center-based Prospective Study was initially developed for and validated in rural residents. However, the validity of estimates based on this FFQ for urban residents, whose diet and lifestyle differ from those of rural residents, has not been clarified. We examined the validity of ranking individuals according to level of dietary consumption, as estimated by this FFQ, among an urban population in Japan.
  
  
  METHODS
  Among 896 candidates randomly selected from examinees of cancer screening provided by the National Cancer Center, Japan, 144 participated in the study. In 2007-2008, at an average 2.7 years after cancer screening, participants were asked to respond to the questionnaire and to provide 4-day weighed diet records (4d-DRs) for use as the reference intake. Spearman correlation coefficients (CCs) between the FFQ and 4d-DR estimates were calculated, after correction for intraindividual variation of 4d-DRs.
  
  
  RESULTS
  The median (range) deattenuated CC for men and women was 0.57 (0.23 to 0.89) and 0.47 (0.08 to 0.94), respectively, across 45 nutrients and 0.51 (0.10 to 0.98) and 0.51 (-0.36 to 0.88) for 43 food groups.
  
  
  CONCLUSIONS
  Although the FFQ was developed for a rural population, it provided reasonably valid measures of consumption for many nutrients and food groups in middle-aged screenees living in urban areas in Japan.
authors.affiliation: Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan.
authors.forename: Ribeka
authors.initials: R
authors.lastname: Takachi
authors.forename: Junko
authors.initials: J
authors.lastname: Ishihara
authors.forename: Motoki
authors.initials: M
authors.lastname: Iwasaki
authors.forename: Satoko
authors.initials: S
authors.lastname: Hosoi
authors.forename: Yuri
authors.initials: Y
authors.lastname: Ishii
authors.forename: Shizuka
authors.initials: S
authors.lastname: Sasazuki
authors.forename: Norie
authors.initials: N
authors.lastname: Sawada
authors.forename: Taiki
authors.initials: T
authors.lastname: Yamaji
authors.forename: Taichi
authors.initials: T
authors.lastname: Shimazu
authors.forename: Manami
authors.initials: M
authors.lastname: Inoue
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Tsugane
mesh_terms: D000328:Adult; D000368:Aged; D004032:Diet / Q000706:statistics & numerical data*; D015930:Diet Records; D004034:Diet Surveys; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009369:Neoplasms / Q000175:diagnosis; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D014505:Urban Population