title: Validity of the Food Frequency Questionnaire Assessing the Folate Intake in Women of Reproductive Age Living in a Country without Food Fortification: Application of the Method of Triads.
abstract: The study aimed to examine the external validity of the Folate Food Frequency Questionnaire (F-FFQ) designed for assessing the folate intake in Serbian women of reproductive age. The F-FFQ was tested against repeated 24 h dietary recalls and correspondent nutritional biomarkers (red blood cells (RBC) and serum folate concentrations) using the method of triads. In a cross sectional study, 503 women aged 18-49 years completed dietary questionnaires and representative validation subsample (n= 50) provided fasting blood samples for biomarker analyses. Correlation coefficients were calculated between each of the dietary methods and three pair-wise correlations were applied for the calculation of validity coefficients. Correlation coefficients observed between F-FFQ and three 24 h recalls werer= 0.56 (p< 0.001) andr= 0.57 (p< 0.001) for total sample and validation group, respectively. Bland-Altman plot and cross-classification analyses indicated good agreement between methods. High validity coefficients were determined between the true intake (I) and dietary assessment methods, F-FFQ (Q) and 24 h dietary recalls (R) (ρQIrbc= 0.871 and ρQIser= 0.814; ρRIrbc= 0.652 and ρRIser= 0.698), and moderate ones for biomarkers (B) (ρBIrbc= 0.428 and ρBIser= 0.421). The F-FFQ is valid instrument for the assessment of dietary folate intake in women living in Serbia, a country without mandatory folic acid food fortification.
authors.affiliation: Centre of Research Excellence in Nutrition and Metabolism, Institute for Medical Research (IMR), University of Belgrade, Tadeusa Koscuska 1, 11158 Belgrade, Serbia. zekovicmilica@gmail.com.
authors.forename: Milica
authors.initials: M
authors.lastname: Zekovic
authors.affiliation: Centre of Research Excellence in Nutrition and Metabolism, Institute for Medical Research (IMR), University of Belgrade, Tadeusa Koscuska 1, 11158 Belgrade, Serbia. djekic.ivankovic@gmail.com.
authors.forename: Marija
authors.initials: M
authors.lastname: Djekic-Ivankovic
authors.affiliation: Centre of Research Excellence in Nutrition and Metabolism, Institute for Medical Research (IMR), University of Belgrade, Tadeusa Koscuska 1, 11158 Belgrade, Serbia. marina.nikolic12@yahoo.com.
authors.forename: Marina
authors.initials: M
authors.lastname: Nikolic
authors.affiliation: Centre of Research Excellence in Nutrition and Metabolism, Institute for Medical Research (IMR), University of Belgrade, Tadeusa Koscuska 1, 11158 Belgrade, Serbia. mirjana.gurinovic@gmail.com.
authors.forename: Mirjana
authors.initials: M
authors.lastname: Gurinovic
authors.affiliation: Department of Social Pharmacy and Pharmaceutical Legislation, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11000 Belgrade, Serbia. dusica.krajnovic@pharmacy.bg.ac.rs.
authors.forename: Dusanka
authors.initials: D
authors.lastname: Krajnovic
authors.affiliation: Centre of Research Excellence in Nutrition and Metabolism, Institute for Medical Research (IMR), University of Belgrade, Tadeusa Koscuska 1, 11158 Belgrade, Serbia. mglibetic@gmail.com.
authors.forename: Marija
authors.initials: M
authors.lastname: Glibetic
mesh_terms: D000293:Adolescent; D000328:Adult; D000886:Anthropometry; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D004032:Diet; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000097:blood; D005527:Food, Fortified; D006801:Humans; D011939:Mental Recall; D008875:Middle Aged; D015596:Nutrition Assessment; D015203:Reproducibility of Results; D012098:Reproduction; D055771:Serbia; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D015415:Biomarkers; D005492:Folic Acid
keywords: FFQ; folate; method of triads; validation; women