title: Reproducibility and validity of coffee and tea consumption in Italy.
abstract: OBJECTIVE
  The reproducibility and validity of coffee, decaffeinated coffee and tea intake has not been adequately studied, particularly in Italy, where coffee drinking is peculiar in terms of type and amount of coffee consumed.
  
  
  METHODS
  We compared coffee and tea consumption, measured by two interviewer-administered food frequency questionnaires (FFQ), with average intake derived from two 7-day dietary (DD) records (the reference method) on 395 volunteers. The Pearson correlation coefficients (r) were used to assess both reproducibility and validity of information on coffee intake.
  
  
  RESULTS
  A satisfactory level of reproducibility and validity of the pattern consumption was observed for coffee, decaffeinated coffee and tea. The reproducibility for both sex combined showed r of 0.74-0.78 for coffee, 0.57-0.65 for decaffeinated coffee and 0.61-0.67 for tea. The validity was about 0.70 for coffee, around 0.58 for decaffeinated coffee and 0.56-0.60 for tea intake.
  
  
  CONCLUSIONS
  The FFQ is a satisfactorily reliable and valid instrument for collecting information on coffee, decaffeinated coffee and tea intake.
authors.affiliation: Dipartimento di Medicina, Chirurgia e Odontoiatria, Università di Milano, Polo San Paolo, Milano, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Ferraroni
authors.forename: A
authors.initials: A
authors.lastname: Tavani
authors.forename: A
authors.initials: A
authors.lastname: Decarli
authors.forename: S
authors.initials: S
authors.lastname: Franceschi
authors.forename: M
authors.initials: M
authors.lastname: Parpinel
authors.forename: E
authors.initials: E
authors.lastname: Negri
authors.forename: C
authors.initials: C
authors.lastname: La Vecchia
mesh_terms: D000328:Adult; D017677:Age Distribution; D015992:Body Mass Index; D003069:Coffee; D004034:Diet Surveys; D004522:Educational Status; D004812:Epidemiologic Methods; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D017678:Sex Distribution; D011795:Surveys and Questionnaires; D013662:Tea
chemical_list: D003069:Coffee; D013662:Tea