title: [Validity and reproducibility of a food frequency questionnaire to estimate folate intake in a Mexican population].
abstract: OBJECTIVE
  To evaluate the reproducibility and validity of folate intake (FI) estimated from a food frequency questionnaire (FFQ), taking into account the retention factor (RF) associated with meal preparation processes.
  
  
  METHODS
  A total of 497 healthy adult participants were interviewed with a FFQ. A second interview was performed one year later of a sample of 100 randomly selected individuals who had not modified their diet during the previous year. In addition,serum folate (SF) concentrations were measured by radioimmunoassay to evaluate the validity of FI.
  
  
  RESULTS
  Reproducibility of IF was 0.36 and 0.34 for folate without FR and with FR, respectively. SF concentration significantly correlated with FI (0.18 with RF; 0.21 without RF, p<0.05).
  
  
  CONCLUSIONS
  Incorporating the folate RF in estimates of FI does not improve the reproducibility and validity of those estimates.
authors.affiliation: Centro de Investigación en Salud Poblacional, Instituto Nacional de Salud Pública, México. mgalvan@insp.mx
authors.forename: Marcia
authors.initials: M
authors.lastname: Galván-Portillo
authors.forename: Luisa
authors.initials: L
authors.lastname: Torres-Sánchez
authors.forename: Raúl Ulises
authors.initials: RU
authors.lastname: Hernández-Ramírez
authors.forename: Miriam Aracely
authors.initials: MA
authors.lastname: Anaya-Loyola
mesh_terms: D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000453:epidemiology; D000465:Algorithms; D000886:Anthropometry; D004032:Diet / Q000706:statistics & numerical data*; D004522:Educational Status; D005247:Feeding Behavior; D005260:Female; D005492:Folic Acid / Q000097:blood; D005494:Folic Acid Deficiency / Q000453:epidemiology; D006801:Humans; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D015203:Reproducibility of Results; D012494:Sampling Studies; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology; D011795:Surveys and Questionnaires
chemical_list: D005492:Folic Acid