title: Some statistical aspects of food intake assessment.
abstract: OBJECTIVE
  To present the results of the statistical working group of the EFCOSUM project on estimating the minimum sample size for a pan-European dietary survey.
  
  
  METHODS
  Numerous statistical issues are involved when planning a nutritional survey aimed at evaluating various indicators, especially if it will be carried out in different countries. The plenary workshop of the EFCOSUM project has chosen four relevant statistical topics: the sample size estimation for dietary surveys, the number of repeated measurements needed to estimate usual intake for each individual; the statistical presentation of data; and the statistical procedures for estimating the usual intake distribution from a limited number of days of observation. This article deals with the first three topics mentioned. The participants of the EFCOSUM project answered a small questionnaire in order to get agreement on the method of estimating a minimum sample size in the context of a monitoring of dietary indicators. Data on the variability of dietary indicators of interest was also collected, in order to calculate a minimum sample size.
  
  
  CONCLUSIONS
  The main result was that a minimum sample size of 2000 adults in each European country will be needed in order to identify trends in the mean intake of the most relevant foods and nutrients in Europe. This sample size should be higher if trends have to be indentified for socio-demographic subgroups.
authors.affiliation: Afssa French Food Safety Agency, Maisons-Alfort, France. jl.volatier@afssa.fr
authors.forename: J L
authors.initials: JL
authors.lastname: Volatier
authors.forename: A
authors.initials: A
authors.lastname: Turrini
authors.forename: D
authors.initials: D
authors.lastname: Welten
mesh_terms: D003627:Data Interpretation, Statistical; D004034:Diet Surveys; D005062:European Union; D005247:Feeding Behavior; D006801:Humans; D015596:Nutrition Assessment; D018401:Sample Size; D013223:Statistics as Topic; D011795:Surveys and Questionnaires