title: Assessing lifetime diet: reproducibility of a self-administered, non-quantitative FFQ.
abstract: OBJECTIVE
  To demonstrate test-retest reliability (reproducibility) of a new self-administered lifetime diet questionnaire, with a focus on foods relevant to cognitive health in older age.
  
  
  METHODS
  The reproducibility of dietary recall over four or five life periods was assessed by administering the questionnaire at two time points to an older cohort. The period between questionnaire administrations was 7 weeks. Polychoric correlations measured the association between recall at time 1 and time 2 and the weighted κ statistic measured the level of recall agreement for food groups across the two administrations of the questionnaire.
  
  
  METHODS
  Adelaide, South Australia.
  
  
  METHODS
  Fifty-two cognitively healthy, older-age, community-dwelling adults completed the Lifetime Diet Questionnaire; mean age 81·8 (SD 4·4) years, range 70-90 years.
  
  
  RESULTS
  The questionnaire showed very good reproducibility in this sample with a mean polychoric correlation coefficient of 0·81 between administration at time 1 and time 2, and an average weighted κ of 0·49 for the level of recall agreement between food groups.
  
  
  CONCLUSIONS
  The demonstrated reliability of this lifetime diet questionnaire makes it a useful tool to assess potential relationships between long-term dietary intake and later-age cognitive outcomes.
authors.affiliation: School of Psychology, University of Adelaide, Adelaide, South Australia, Australia. Diane.Hosking@csiro.au
authors.forename: Diane
authors.initials: D
authors.lastname: Hosking
authors.forename: Vanessa
authors.initials: V
authors.lastname: Danthiir
authors.forename: Ted
authors.initials: T
authors.lastname: Nettelbeck
authors.forename: Carlene
authors.initials: C
authors.lastname: Wilson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology*; D004032:Diet / Q000706:statistics & numerical data*; D004034:Diet Surveys; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall; D015596:Nutrition Assessment; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013021:South Australia; D011795:Surveys and Questionnaires / Q000592:standards*