Validation of a food-frequency questionnaire for cohort studies in rural Japan.
OBJECTIVE
To examine the validity and reproducibility of a self-administered food-frequency questionnaire (FFQ) used for two cohort studies in Japan.


METHODS
Cross-sectional study.


METHODS
Two rural towns in the Miyagi Prefecture, in north-eastern Japan.


METHODS
Fifty-five men and 58 women.


RESULTS
A 40-item FFQ was administered twice, 1 year apart. In the mean time, four 3-day diet records (DRs) were collected in four seasons within the year. We calculated daily consumption of total energy and 15 nutrients, 40 food items and nine food groups from the FFQs and the DRs. We computed Spearman correlation coefficients between the FFQs and the DRs. With adjustment for age, total energy and deattenuation for measurement error with the DRs, the correlation coefficients for nutrient intakes ranged from 0.25 to 0.58 in men and from 0.30 to 0.69 in women, with median of 0.43 and 0.43, respectively. Median (range) of the correlation coefficients was 0.35 (-0.30 to 0.72) in men and 0.34 (-0.06 to 0.75) in women for food items and 0.60 (-0.10 to 0.76) and 0.51 (0.28-0.70) for food groups, respectively. Median (range) of the correlation coefficients for the two FFQs administered 1 year apart was 0.49 (0.31-0.71) in men and 0.50 (0.40-0.64) in women for nutrients, 0.43 (0.14-0.76) and 0.45 (0.06-0.74) respectively for food items, and 0.50 (0.30-0.70) and 0.57 (0.39-0.66) respectively for food groups. Relatively higher agreement percentages for intakes of nutrients and food groups with high validity were obtained together with lower complete disagreement percentages.


CONCLUSIONS
The FFQ has a high reproducibility and a reasonably good validity, and is useful in assessing the usual intakes of nutrients, foods and food groups among a rural Japanese population.
Ogawa
Keiko
K
Division of Epidemiology, Department of Public Health, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan.
Tsubono
Yoshitaka
Y
Nishino
Yoshikazu
Y
Watanabe
Yoko
Y
Ohkubo
Takayoshi
T
Watanabe
Takao
T
Nakatsuka
Haruo
H
Takahashi
Nobuko
N
Kawamura
Mieko
M
Tsuji
Ichiro
I
Hisamichi
Shigeru
S
D000368:Aged; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D015930:Diet Records; D004034:Diet Surveys; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012424:Rural Population; D012621:Seasons; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires / Q000592:standards*