title: Reproducibility and Validity of a Food Frequency Questionnaire Designed to Assess Diet in Children Aged 4-5 Years.
abstract: BACKGROUND
  The food frequency questionnaire (FFQ) is the most efficient and cost-effective method to investigate the relationship between usual diet and disease in epidemiologic studies. Although FFQs have been validated in many adult populations worldwide, the number of valid FFQ in preschool children is very scarce. The aim of this study was to evaluate the reproducibility and validity of a semi-quantitative FFQ designed for children aged 4 to 5 years.
  
  
  METHODS
  In this study, we have included 169 children aged 4-5 years from the INMA project in Valencia, a population-based prospective cohort study of mothers and children in Spain. The 105-items FFQ was administered twice to the parents or care-givers of children over a 9-month period. Reproducibility was explored by comparing intake of nutrients by the FFQs, while validity was examined by comparing the nutrient values from the FFQs with the average nutrient values of three 24 hour dietary recall (24hDR) taken in the period, and also, with the concentration in blood specimens for several vitamins (carotenoids, folate, vitamin B12, vitamin C and α-tocopherol). Pearson correlation coefficients and de-attenuated correlation coefficients were calculated and we also evaluated misclassification by quintile distribution.
  
  
  RESULTS
  All correlation coefficients for reproducibility for nutrients and major food groups were statistically significant; the average correlation coefficients for daily intake were 0.43 for food groups and 0.41 for nutrients. The average correlation coefficients for validity for daily intakes against 24hDR was r = 0.30, and the average for de-attenuated correlation coefficients was r = 0.44. When evaluating validity against the blood concentration of vitamins, statistically significant correlations were observed for vitamin C (0.35), lycopene (0.31), β-Cryptoxantin (0.40), and vitamin E (0.29); the average of correlation coefficients was r = 0.21.
  
  
  CONCLUSIONS
  Despite some low to moderate correlations for reproducibility and validity, overall this study suggests that the FFQ may be a good method for assessing a wide range of food groups and nutrients intake in children aged 4-5 years.
authors.affiliation: Unidad de Epidemiologia de la Nutrición. Universidad Miguel Hernández, Alicante, Spain. Institute for Health and Biomedical Research (ISABIAL-FISABIO Foundation), Alicante, Spain.|CIBER de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain.
authors.forename: Jesus
authors.initials: J
authors.lastname: Vioque
authors.affiliation: Unidad de Epidemiologia de la Nutrición. Universidad Miguel Hernández, Alicante, Spain. Institute for Health and Biomedical Research (ISABIAL-FISABIO Foundation), Alicante, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Gimenez-Monzo
authors.affiliation: Unidad de Epidemiologia de la Nutrición. Universidad Miguel Hernández, Alicante, Spain. Institute for Health and Biomedical Research (ISABIAL-FISABIO Foundation), Alicante, Spain.|CIBER de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain.
authors.forename: Eva Maria
authors.initials: EM
authors.lastname: Navarrete-Muñoz
authors.affiliation: Unidad de Epidemiologia de la Nutrición. Universidad Miguel Hernández, Alicante, Spain. Institute for Health and Biomedical Research (ISABIAL-FISABIO Foundation), Alicante, Spain.|CIBER de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain.
authors.forename: Manuela
authors.initials: M
authors.lastname: Garcia-de-la-Hera
authors.affiliation: Unidad de Epidemiologia de la Nutrición. Universidad Miguel Hernández, Alicante, Spain. Institute for Health and Biomedical Research (ISABIAL-FISABIO Foundation), Alicante, Spain.
authors.forename: Sandra
authors.initials: S
authors.lastname: Gonzalez-Palacios
authors.affiliation: CIBER de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain.|Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO/CSISP), Valencia, Spain.|Departamento de Medicina, Universitat Jaume I, Castellón de la Plana, Spain.
authors.forename: Marisa
authors.initials: M
authors.lastname: Rebagliato
authors.affiliation: CIBER de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain.|Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO/CSISP), Valencia, Spain.
authors.forename: Ferran
authors.initials: F
authors.lastname: Ballester
authors.affiliation: CIBER de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain.|Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO/CSISP), Valencia, Spain.
authors.forename: Mario
authors.initials: M
authors.lastname: Murcia
authors.affiliation: CIBER de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain.|Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO/CSISP), Valencia, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Iñiguez
authors.affiliation: Servicio Bioquímica Clínica, Hospital Universitario Puerta de Hierro-Majadahonda, Madrid, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Granado
mesh_terms: D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D017028:Caregivers / Q000523:psychology; D002675:Child, Preschool; D015331:Cohort Studies; D004034:Diet Surveys / Q000592:standards*; D002149:Energy Intake; D004812:Epidemiologic Methods; D004813:Epidemiology; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results; D014815:Vitamins / Q000097:blood
chemical_list: D015415:Biomarkers; D014815:Vitamins