Ma. Cardoso et al., Reproducibility and validity of a food frequency questionnaire among womenof Japanese ancestry living in Brazil, NUTR RES, 21(5), 2001, pp. 725-733
A 120-item food frequency questionnaire (FFQ) was assessed among Female Reg
istered Dietitians of Japanese ancestry living in Sao Paulo, Brazil. The re
producibility of the FFQ was assessed by repeated administration at one-mon
th interval (n = 77). The relative validity was evaluated by comparison wit
h dietary intake obtained from 4 three-day weighed dietary records (DR), co
vering the same 12-month period assessed by the FFQ (n = 52). Reproducibili
ty: Pearson correlation coefficients for 24 energy-adjusted nutrients range
d from 0.52 for protein to 0.75 for retinol. Validity: Pearson correlation
coefficients between the mean energy-adjusted intakes from the DR and those
from the FFQ ranged from 0.27 for sodium to 0.68 for dietary fiber without
supplements. These correlations were higher after adjusting for day-to-day
variation in DR intakes. We conclude that this FFQ is reproducible and can
be used to classify persons according to their nutrient intake over a one-
year period. (C) 2001 Elsevier Science Inc. Ah rights reserved.