title: Comparability of dietary patterns assessed by multiple dietary assessment methods: results from the 1946 British Birth Cohort.
abstract: OBJECTIVE
  The aim of this study is to evaluate the consistency of dietary patterns assessed through the use of a dietary recall and a 5-day food diary.
  
  
  METHODS
  Participants (n = 2265) of a longitudinal study of health and development completed 48-h dietary recall at interview, followed by a 5-day food diary and with the 24 h immediately preceding the interview analysed separately as a 24-h recall. Mean intakes of foods and nutrients were calculated and dietary patterns were assessed using exploratory factor analysis, using the method of principal components. Paired t-tests and correlation coefficients were used to compare the three dietary assessment methods.
  
  
  RESULTS
  Five distinct dietary patterns were identified using the food diary and the 48-h recall but were less consistent on the 24-h recall. Correlations between factor scores on the 48-h recall and the food diary (r = 0.13-0.67) were higher than those between the 24-h recall and food diary (r = -0.01-0.59). The recall methods were effective at ranking subjects according to food and nutrient intakes, with the 48-h recall and food diary showing higher correlations in both males and females.
  
  
  CONCLUSIONS
  This study indicates that a 48-h recall effectively characterises dietary patterns in British adults when compared to a food diary and ranks participants appropriately with respect to most nutrients and foods and is superior to a single 24-h recall. These results have implications for longitudinal studies where maximising response rates to repeat dietary assessment tools is essential.
authors.affiliation: MRC Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, UK.
authors.forename: S A
authors.initials: SA
authors.lastname: McNaughton
authors.forename: G D
authors.initials: GD
authors.lastname: Mishra
authors.forename: G
authors.initials: G
authors.lastname: Bramwell
authors.forename: A A
authors.initials: AA
authors.lastname: Paul
authors.forename: M E J
authors.initials: ME
authors.lastname: Wadsworth
mesh_terms: D015331:Cohort Studies; D015930:Diet Records; D004034:Diet Surveys; D004435:Eating; D005163:Factor Analysis, Statistical; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D015596:Nutrition Assessment; D006113:United Kingdom