title: Validity and reproducibility of a food frequency questionnaire focused on the Mediterranean diet for the Quebec population.
abstract: OBJECTIVE
  Validated dietary assessment methods specific to population and food habits are needed to conduct randomized clinical trials evaluating the efficacy of the Mediterranean diet in primary and secondary prevention of cardiovascular disease. Therefore, the aim of our study was to assess the reproducibility and the relative validity of a French language semi-quantitative food frequency questionnaire (FFQ) focused on the Mediterranean diet within the population of Quebec.
  
  
  RESULTS
  Fifty-three participants aged 19-86 years with and without coronary heart disease were recruited, and randomized in 3 groups in a crossover design where the sequence of administration of two FFQs and a dietary record (DR) differed in each group. The FFQ includes 157 food items and was designed to measure food intake over one month. It was administered twice 3-5 weeks apart to assess reproducibility and was compared to a 12-day DR to assess validity. For reproducibility (n = 47), intraclass correlation coefficients (ICCs) for energy and 33 nutrients ranged from 0.38 to 0.91 (mean 0.63). For validity, the Pearson's correlation coefficients between the DR and the FFQ pre-DR ranged from 0.26 to 0.84 (mean 0.55) and ICCs ranged from 0.25 to 0.84 (mean 0.54). As for the DR and the FFQ post-DR, the Pearson's correlation coefficients ranged from 0.36 to 0.83 (mean 0.55) and the ICCs ranged from 0.36 to 0.83 (mean 0.53).
  
  
  CONCLUSIONS
  This FFQ demonstrates good reproducibility and validity for most key nutrients of the Mediterranean diet for the Quebec population.
authors.affiliation: Montreal Heart Institute, Prevention and Physical Activity Center, Université de Montréal, Canada; Department of Nutrition, Faculty of Medicine, Université de Montréal, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Cantin
authors.affiliation: Montreal Heart Institute, Prevention and Physical Activity Center, Université de Montréal, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Latour
authors.affiliation: Montreal Heart Institute, Prevention and Physical Activity Center, Université de Montréal, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Ferland-Verry
authors.affiliation: Université du Québec à Montréal, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Morales Salgado
authors.affiliation: Department of Social and Preventive Medicine, School of Public Health, Université de Montréal, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Lambert
authors.affiliation: Department of Nutrition, Faculty of Medicine, Université de Montréal, Canada; Institut de Recherches Cliniques de Montréal (IRCM), Canada.
authors.forename: M
authors.initials: M
authors.lastname: Faraj
authors.affiliation: Montreal Heart Institute, Prevention and Physical Activity Center, Université de Montréal, Canada; Department of Nutrition, Faculty of Medicine, Université de Montréal, Canada. Electronic address: anil.nigam@icm-mhi.org.
authors.forename: A
authors.initials: A
authors.lastname: Nigam
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018592:Cross-Over Studies; D015930:Diet Records; D038441:Diet, Mediterranean; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D011792:Quebec; D011897:Random Allocation; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D013997:Time Factors; D055815:Young Adult
keywords: Dietary record; Food frequency questionnaire; Mediterranean diet; Reproducibility; Validity