title: Validation of a food frequency questionnaire for children and adolescents aged 4 to 11 years living in Salvador, Bahia.
abstract: OBJECTIVE
  To assess the validity of a food frequency questionnaire (FFQ) by applying it to children and adolescents living in Salvador, Bahia.
  
  
  METHODS
  The validity of this FFQ with 98 food items was investigated among 108 children and adolescents who were selected from a sample of 1445 that had been planned for a study on the risk factors for asthma and other allergic diseases. The adults responsible for these children and adolescents gave responses for a 24-hour recall (R24h) and an FFQ. The average energy and nutrient values from the FFQ were compared with those from the R24h by means of the paired t test and Pearson correlation coefficients. The concordance was evaluated using the Bland-Altman method and kappa statistics.
  
  
  RESULTS
  The energy and nutrient intake estimated using the FFQ was significantly higher than what was obtained using the R24h. The correlation coefficients adjusted for energy were statistically significant for protein, fat, vitamin C and zinc. The weighted kappa values ranged from 0.06 for vitamin A (p = 0.24) to 0.34 for energy (p < 0.00). The results from the Bland-Altman plots for lipid, protein and zinc showed the most significant validity parameters, and zinc was found to show the best concordance.
  
  
  CONCLUSIONS
  The results suggest that the FFQ showed satisfactory validity for use in studies involving children and adolescents.
authors.affiliation: Instituto da Saúde Coletiva, Universidade Federal da Bahia, Salvador, Bahia, Brazil. sheilaalvim@hotmail.com
authors.forename: S M A
authors.initials: SM
authors.lastname: Matos
authors.forename: M S
authors.initials: MS
authors.lastname: Prado
authors.forename: C A S T
authors.initials: CA
authors.lastname: Santos
authors.forename: S
authors.initials: S
authors.lastname: D'Innocenzo
authors.forename: A M O
authors.initials: AM
authors.lastname: Assis
authors.forename: L S
authors.initials: LS
authors.lastname: Dourado
authors.forename: N S
authors.initials: NS
authors.lastname: Oliveira
authors.forename: L C
authors.initials: LC
authors.lastname: Rodrigues
authors.forename: M L
authors.initials: ML
authors.lastname: Barreto
mesh_terms: D000293:Adolescent; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003627:Data Interpretation, Statistical; D004034:Diet Surveys; D004435:Eating; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires