title: Validity of an FFQ assessing the vitamin D intake of young Serbian women living in a region without food fortification: the method of triads model.
abstract: OBJECTIVE
  The objective of the present study was to examine the external validity of an FFQ designed to estimate dietary vitamin D intake compared with a plasma biomarker and three repeated 24 h dietary recalls in women of reproductive age in Serbia, where there is no exposure to food fortified with vitamin D. The method of triads was applied.
  
  
  METHODS
  In a cross-sectional study, 422 women completed the Women and Reproductive Health FFQ (WRH-FFQ) during the winter months. From a representative subgroup (n 44), three 24 h dietary recalls and anthropometric parameters were collected as well as a fasting blood sample for vitamin D biomarker analyses. Correlation coefficients were calculated between each of the dietary methods. Validity coefficients, as a correlation between the measured and estimated 'true' exposure, were calculated using the method of triads. Bland-Altman plots were also constructed.
  
  
  METHODS
  Three major universities in Serbia.
  
  
  METHODS
  Healthy young women (n 422) aged 18-35 years.
  
  
  RESULTS
  The WRH-FFQ estimate of vitamin D intake for all participants was 4.0 (sd 3.3) µg/d and 3.1 (sd 2.3) µg/d for the subgroup. Bland-Altman plots for these intakes showed high agreement. Validity coefficients for the FFQ, 24 h recall and biomarker were ρ QI=0.847 (95% CI 0.564, 0.928), ρ RI=0.810 (95% CI 0.537, 0.997) and ρ BI=0.499 (95% CI 0.190, 0.840), while the correlation coefficients were 0.686, 0.422 and 0.404.
  
  
  CONCLUSIONS
  The FFQ applied in the present study is a valid tool for assessing dietary vitamin D intake in women living in Serbia, a region without mandatory vitamin D food fortification.
authors.affiliation: 1Centre of Research Excellence in Nutrition and Metabolism,Institute for Medical Research,University of Belgrade,Tadeusa Koscuska 1,11000 Belgrade,Serbia.
authors.forename: Marija
authors.initials: M
authors.lastname: Djekic-Ivankovic
authors.affiliation: 2School of Dietetics and Human Nutrition,McGill University,Macdonald Campus,Ste. Anne-de-Bellevue,Québec,Canada.
authors.forename: Hope A
authors.initials: HA
authors.lastname: Weiler
authors.affiliation: 1Centre of Research Excellence in Nutrition and Metabolism,Institute for Medical Research,University of Belgrade,Tadeusa Koscuska 1,11000 Belgrade,Serbia.
authors.forename: Marina
authors.initials: M
authors.lastname: Nikolic
authors.affiliation: 1Centre of Research Excellence in Nutrition and Metabolism,Institute for Medical Research,University of Belgrade,Tadeusa Koscuska 1,11000 Belgrade,Serbia.
authors.forename: Agnes
authors.initials: A
authors.lastname: Kadvan
authors.affiliation: 1Centre of Research Excellence in Nutrition and Metabolism,Institute for Medical Research,University of Belgrade,Tadeusa Koscuska 1,11000 Belgrade,Serbia.
authors.forename: Mirjana
authors.initials: M
authors.lastname: Gurinovic
authors.affiliation: 3Faculty of Chemistry,University of Belgrade,Belgrade,Serbia.
authors.forename: Ljuba M
authors.initials: LM
authors.lastname: Mandic
authors.affiliation: 1Centre of Research Excellence in Nutrition and Metabolism,Institute for Medical Research,University of Belgrade,Tadeusa Koscuska 1,11000 Belgrade,Serbia.
authors.forename: Maria
authors.initials: M
authors.lastname: Glibetic
mesh_terms: D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D002149:Energy Intake; D005260:Female; D005527:Food, Fortified; D006801:Humans; D011939:Mental Recall; D015596:Nutrition Assessment; D009752:Nutritional Status; D012621:Seasons; D055771:Serbia; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000008:administration & dosage* / Q000097:blood; D055815:Young Adult
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D014807:Vitamin D
keywords: FFQ; Method of triads; Reproductive health; Validation; Vitamin D; Women