title: Assessing the accuracy of a food frequency questionnaire for estimating usual intake of phytoestrogens.
abstract: The primary objective of this study was to assess the accuracy of a modified Block food frequency questionnaire (FFQ) with respect to its ability to assess usual dietary intakes of daidzein and genistein. Participants were a convenience sample of 51 Japanese and 18 Caucasian women. All interviews were conducted between February 1997 and October 1997. At each of the four study visits, participants provided a 24-hour urine specimen and a 48-hour dietary recall. At the first visit, participants also completed an interviewer-administered modified Block FFQ. The daidzein and genistein intakes estimated using the FFQ were moderately correlated with the mean estimates of daidzein and genistein intake calculated from four 48-hour dietary recalls (correlation for daidzein = 0.49-0.58 and correlation for genistein = 0.45-0.54) and estimates of urinary concentrations of these compounds calculated from four collections (correlations for daidzein and genistein = 0.49 and 0.30, respectively). The accuracy of the modified Block FFQ for assessment of usual daidzein and genistein intakes is supported by this study. These results support the use of this instrument in epidemiological studies as an easy and low-cost method to assess the usual dietary daidzein or genistein intake.
authors.affiliation: Department of Epidemiology, Division of Geriatrics, School of Medicine, University of California, Los Angeles, CA 90095, USA. mhuang@ucla.edu
authors.forename: M H
authors.initials: MH
authors.lastname: Huang
authors.forename: G G
authors.initials: GG
authors.lastname: Harrison
authors.forename: M M
authors.initials: MM
authors.lastname: Mohamed
authors.forename: J A
authors.initials: JA
authors.lastname: Gornbein
authors.forename: S M
authors.initials: SM
authors.lastname: Henning
authors.forename: V L
authors.initials: VL
authors.lastname: Go
authors.forename: G A
authors.initials: GA
authors.lastname: Greendale
mesh_terms: D016588:Anticarcinogenic Agents / Q000008:administration & dosage* / Q000652:urine; D001213:Asian; D015930:Diet Records; D004968:Estrogens, Non-Steroidal / Q000008:administration & dosage* / Q000652:urine; D005260:Female; D019833:Genistein / Q000008:administration & dosage* / Q000652:urine; D006801:Humans; D007407:Interviews as Topic; D007529:Isoflavones / Q000008:administration & dosage* / Q000652:urine; D011939:Mental Recall; D048789:Phytoestrogens; D028321:Plant Preparations; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires; D016482:Urinalysis; D044465:White People
chemical_list: D016588:Anticarcinogenic Agents; D004968:Estrogens, Non-Steroidal; D007529:Isoflavones; D048789:Phytoestrogens; D028321:Plant Preparations; C004742:daidzein; D019833:Genistein