title: Race-specific validation of food intake obtained from a comprehensive FFQ: the Adventist Health Study-2.
abstract: OBJECTIVE
  To assess race-specific validity of food and food group intakes measured using an FFQ.
  
  
  METHODS
  Calibration study participants were randomly selected from the Adventist Health Study-2 (AHS-2) cohort by church, and then by subject-within-church. Intakes of forty-seven foods and food groups were assessed using an FFQ and then compared with intake estimates measured using six 24 h dietary recalls (24HDR). We used two approaches to assess the validity of the questionnaire: (i) cross-classification by quartile and (ii) de-attenuated correlation coefficients.
  
  
  METHODS
  Seventh-day Adventist church members geographically spread throughout the USA and Canada.
  
  
  METHODS
  Members of the AHS-2 calibration study (550 whites and 461 blacks).
  
  
  RESULTS
  The proportion of participants with exact quartile agreement in the FFQ and 24HDR averaged 46 % (range: 29-87 %) in whites and 44 % (range: 25-88 %) in blacks. The proportion of quartile gross misclassification ranged from 1 % to 11 % in whites and from 1 % to 15 % in blacks. De-attenuated validity correlations averaged 0·59 in whites and 0·48 in blacks. Of the forty-seven foods and food groups, forty-three in whites and thirty-three in blacks had validity correlations >0·4.
  
  
  CONCLUSIONS
  The AHS-2 questionnaire has good validity for most foods in both races; however, validity correlations tend to be higher in whites than in blacks.
authors.affiliation: Department of Nutrition, School of Public Health, Loma Linda University, 24785 Stewart Street, EH 203, Loma Linda, CA 92350, USA. kjaceldo@llu.edu
authors.forename: Karen
authors.initials: K
authors.lastname: Jaceldo-Siegl
authors.forename: Jing
authors.initials: J
authors.lastname: Fan
authors.forename: Joan
authors.initials: J
authors.lastname: Sabaté
authors.forename: Synnove F
authors.initials: SF
authors.lastname: Knutsen
authors.forename: Ella
authors.initials: E
authors.lastname: Haddad
authors.forename: W Lawrence
authors.initials: WL
authors.lastname: Beeson
authors.forename: R Patti
authors.initials: RP
authors.lastname: Herring
authors.forename: Terrence L
authors.initials: TL
authors.lastname: Butler
authors.forename: Hannelore
authors.initials: H
authors.lastname: Bennett
authors.forename: Gary E
authors.initials: GE
authors.lastname: Fraser
mesh_terms: D000328:Adult; D000368:Aged; D044383:Black People; D002138:Calibration; D002170:Canada; D015331:Cohort Studies; D004032:Diet; D004034:Diet Surveys; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D011795:Surveys and Questionnaires / Q000592:standards*; D014481:United States; D044465:White People; D001741:Black or African American