title: Validation of a semi-quantitative food-frequency questionnaire for use among adults in Guatemala.
abstract: OBJECTIVE
  The purpose of the study was to assess the validity of a 52-item semi-quantitative food-frequency questionnaire (FFQ) by comparing it with multiple 24-hour dietary recalls.
  
  
  METHODS
  Three non-consecutive 24-hour dietary recalls and one FFQ were administered over a one-month period.
  
  
  METHODS
  Four communities of El Progreso, Guatemala.
  
  
  METHODS
  Seventy-three individuals aged 22-55 years.
  
  
  RESULTS
  : Intakes of energy and other nutrients as measured by the FFQ were higher than intakes measured by 24-hour recalls. Energy was overestimated by 361 kcal, and nutrient overestimates were particularly great for vitamin C and iron. Pearson correlation coefficients for crude energy and nutrients intakes ranged from 0.64 for energy to 0.12 for vitamin C. Exact agreement for both methods (measured by the concordance correlation coefficient) ranged from 0.59 (fat) to 0.06 (vitamin C). Pearson correlation coefficients for energy-adjusted nutrients ranged from 0.59 (carbohydrates) to 0.11 (thiamin). Pearson correlation coefficients for the proportion of total energy derived from specific foods ranged from 0.59 (tortillas) to 0.01 (sugared beverages). Cross-classification of quartiles of crude nutrient intakes for both methods indicated that <11% were grossly misclassified; after adjusting for energy intake, <13% were grossly misclassified.
  
  
  CONCLUSIONS
  This FFQ provides good measures of energy and macronutrient intakes and a reasonably reliable measure of micronutrient intake, indicating its suitability for comparing exposures within a study population in reference to heath-related endpoints. Our results highlight the need to adapt any FFQ to specific cultural needs - in this case, the Guatemalan 'core foods' (tortilla, bread and beans), for which inter-individual variability in intake is high.
authors.affiliation: Institute of Nutrition of Central America and Panama (INCAP), Guatemala City, Guatemala.
authors.forename: Monica M
authors.initials: MM
authors.lastname: Rodríguez
authors.forename: Humberto
authors.initials: H
authors.lastname: Méndez
authors.forename: Benjamín
authors.initials: B
authors.lastname: Torún
authors.forename: Dirk
authors.initials: D
authors.lastname: Schroeder
authors.forename: Aryeh D
authors.initials: AD
authors.lastname: Stein
mesh_terms: D000328:Adult; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004041:Dietary Fats / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage*; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D006166:Guatemala; D006801:Humans; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires / Q000592:standards*
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins