title: Validity of the self-administered food frequency questionnaire used in the 5-year follow-up survey of the JPHC Study Cohort I: comparison with dietary records for main nutrients.
abstract: We examined the validity of energy and 16 nutrient intake measurements from a self-administered food frequency questionnaire (FFQ) used in the 5-year follow-up survey of the JPHC study using 28- or 14-day dietary records (DR) as the gold standard. The median (range) correlation coefficients between 16 nutrients measured by FFQ and DR were 0.52 (0.31-0.81) for men and 0.41 (0.22-0.56) for women. The median (range) for energy-adjusted correlation coefficients was 0.40 (0.22-0.82) for men and 0.39 (0.15-0.48) for women. With further adjustment for area, it was 0.41 and 0.35, respectively. The mean percentage of classification into the same categories between the two methods was 33% in men and 30% in women. Only 2% of subjects were classified into the extreme opposite categories. In conclusion, the results suggest that the FFQ can be used in the JPHC Study Cohort I to rank individuals according to the intakes for most of the nutrients examined.
authors.affiliation: Epidemiology and Biostatistics Division, National Cancer Center Research Institute East, Kashiwa, Chiba, Japan.
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Tsugane
authors.forename: Minatsu
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sasaki
mesh_terms: D015930:Diet Records; D004034:Diet Surveys; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D015203:Reproducibility of Results; D012737:Sex Factors; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires