title: Reproducibility and comparative validity of a food frequency questionnaire for Australian adults.
abstract: BACKGROUND
  Food frequency questionnaires (FFQ) are used in epidemiological studies to investigate the relationship between diet and disease. There is a need for a valid and reliable adult FFQ with a contemporary food list in Australia.
  
  
  OBJECTIVE
  To evaluate the reproducibility and comparative validity of the Australian Eating Survey (AES) FFQ in adults compared to weighed food records (WFRs).
  
  
  METHODS
  Two rounds of AES and three-day WFRs were conducted in 97 adults (31 males, median age and BMI for males of 44.9 years, 26.2 kg/m(2), females 41.3 years, 24.0 kg/m(2). Reproducibility was assessed over six months using Wilcoxon signed-rank tests and comparative validity was assessed by intraclass correlation coefficients (ICC) estimated by fitting a mixed effects model for each nutrient to account for age, sex and BMI to allow estimation of between and within person variance.
  
  
  RESULTS
  Reproducibility was found to be good for both WFR and FFQ since there were no significant differences between round 1 and 2 administrations. For comparative validity, FFQ ICCs were at least as large as those for WFR. The ICC of the WFR-FFQ difference for total energy intake was 0.6 (95% CI 0.43, 0.77) and the median ICC for all nutrients was 0.47, with all ICCs between 0.15 (%E from saturated fat) and 0.7 (g/day sugars).
  
  
  CONCLUSIONS
  Compared to WFR the AES FFQ is suitable for reliably estimating the dietary intakes of Australian adults across a wide range of nutrients.
authors.affiliation: School of Health Sciences, Faculty of Health, University of Newcastle, Callaghan, NSW, Australia; Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, Australia. Electronic address: clare.collins@newcastle.edu.au.
authors.forename: Clare E
authors.initials: CE
authors.lastname: Collins
authors.affiliation: School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, USA.
authors.forename: May M
authors.initials: MM
authors.lastname: Boggess
authors.affiliation: School of Health Sciences, Faculty of Health, University of Newcastle, Callaghan, NSW, Australia; Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Jane F
authors.initials: JF
authors.lastname: Watson
authors.affiliation: School of Health Sciences, Faculty of Health, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Maya
authors.initials: M
authors.lastname: Guest
authors.affiliation: School of Health Sciences, Faculty of Health, University of Newcastle, Callaghan, NSW, Australia; Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Kerith
authors.initials: K
authors.lastname: Duncanson
authors.affiliation: School of Health Sciences, Faculty of Health, University of Newcastle, Callaghan, NSW, Australia; Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Kristine
authors.initials: K
authors.lastname: Pezdirc
authors.affiliation: School of Health Sciences, Faculty of Health, University of Newcastle, Callaghan, NSW, Australia; Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Megan
authors.initials: M
authors.lastname: Rollo
authors.affiliation: School of Health Sciences, Faculty of Health, University of Newcastle, Callaghan, NSW, Australia; Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Melinda J
authors.initials: MJ
authors.lastname: Hutchesson
authors.affiliation: School of Health Sciences, Faculty of Health, University of Newcastle, Callaghan, NSW, Australia; Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Tracy L
authors.initials: TL
authors.lastname: Burrows
mesh_terms: D000328:Adult; D000368:Aged; D001315:Australia; D015992:Body Mass Index; D002241:Carbohydrates / Q000032:analysis; D015930:Diet Records; D004040:Dietary Carbohydrates / Q000032:analysis; D004041:Dietary Fats / Q000032:analysis; D004043:Dietary Fiber / Q000032:analysis; D004044:Dietary Proteins / Q000032:analysis; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D018977:Micronutrients / Q000032:analysis; D008875:Middle Aged; D015596:Nutrition Assessment; D009749:Nutrition Surveys; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires
chemical_list: D002241:Carbohydrates; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004043:Dietary Fiber; D004044:Dietary Proteins; D018977:Micronutrients
keywords: Comparative validity; Dietary methods; Food frequency questionnaire; Intra-class correlation coefficient; Nutrition; Reproducibility