title: Development and validation of a semi-quantitative food frequency questionnaire to assess dietary intake in Turkish adults.
abstract: OBJECTIVE
  To validate the original food frequency questionnaire in Turkish adult population.
  
  
  METHODS
  The cross-sectional study was conducted in June and December 2008 and 2009, and comprised adults of either gender aged 30-70 years. All subjects were Caucasians and were native Turkish speakers. The food frequency questionnaire containing 229 most frequently consumed foods under 7 topics was used for data collection. It was completed twice and the 24-hour dietary recall four times in a year. In order to assess the validity of the questionnaire, Pearson correlation, attenuation coefficient, measures of agreement between the two methods, weighted kappa statistics and Bland-Altman plots were employed. SPSS 16 was used for statistical analysis.
  
  
  RESULTS
  Of the 120 subjects in the study, 71(59%) were males and 49(41%) were females with an overall mean age of 50.16±9.76 years. The correlation of estimated nutrient intake between the food frequency questionnaire and 24-hour dietary recall varied between 0.200 and 0.468, energy-adjusted regression was between 0.044 and 0.611 and attenuation coefficients of regression were between 0.339 and 0.658 for the selected macro and micro nutrients. Bland-Altman plots showed an acceptable agreement between the two methods. When nutrient intake was categorised in quartiles, proportions of the same or adjacent quartiles were 98.3%, 98.4%, 98.3%, 96.7% and 95% for energy, fat, protein, carbohydrates and fibre, respectively.
  
  
  CONCLUSIONS
  The first food frequency questionnaire developed in Turkish language was an adequate and valid tool to assess the nutritional habits of the local population.
authors.affiliation: Department of Nutrition and Dietetic, Faculty of Health Sciences, Marmara University, Istanbul, Turkey.
authors.forename: Fatma Esra
authors.initials: FE
authors.lastname: Gunes
authors.affiliation: Department of Gastroenterology, Faculty of Medicine, Gastroenterology Institute, Marmara University, Istanbul, Turkey.
authors.forename: Nese
authors.initials: N
authors.lastname: Imeryuz
authors.affiliation: Department of Family Medicine, Faculty of Medicine, Yeditepe University, Istanbul, Turkey.
authors.forename: Arzu
authors.initials: A
authors.lastname: Akalin
authors.affiliation: Department of Biostatics and Bioinformatics, Faculty of Medicine, Marmara University, Istanbul, Turkey.
authors.forename: Nural
authors.initials: N
authors.lastname: Bekiroglu
authors.affiliation: Department of Nutrition and Dietetic, Faculty of Health Science, Okan University, Istanbul, Turkey.
authors.forename: Emel
authors.initials: E
authors.lastname: Alphan
authors.affiliation: Department of Internal Medicine, Goztepe Training and Research Hospital, Medeniyet University, Istanbul, Turkey.
authors.forename: Aytekin
authors.initials: A
authors.lastname: Oguz
authors.affiliation: Department of Medicine, Population Health Research Institute, McMaster University, Hamilton, Canada.
authors.forename: Mahshid
authors.initials: M
authors.lastname: Dehghan
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D004032:Diet / Q000706:statistics & numerical data*; D004034:Diet Surveys; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004043:Dietary Fiber; D004044:Dietary Proteins; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D014421:Turkey
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004043:Dietary Fiber; D004044:Dietary Proteins
keywords: Food frequency questionnaire (FFQ), 24-hour dietary recall (24HR), Dietary assessment, Validation.