title: Adaptation and evaluation of the National Cancer Institute's Diet History Questionnaire and nutrient database for Canadian populations.
abstract: OBJECTIVE
  Despite assumed similarities in Canadian and US dietary habits, some differences in food availability and nutrient fortification exist. Food-frequency questionnaires designed for the USA may therefore not provide the most accurate estimates of dietary intake in Canadian populations. Hence, we undertook to evaluate and modify the National Cancer Institute's Diet History Questionnaire (DHQ) and nutrient database.
  
  
  METHODS
  Of the foods queried on the DHQ, those most likely to differ in nutrient composition were identified. Where possible these foods were matched to comparable foods in the Canadian Nutrient File. Nutrient values were examined and modified to reflect the Canadian content of minerals (calcium, iron, zinc) and vitamins (A, C, D, thiamin, riboflavin, niacin, B6, folate and B12). DHQs completed by 13 181 Alberta Cohort Study participants aged 35-69 years were analysed to estimate nutrient intakes using the original US and modified versions of the DHQ databases. Misclassification of intake for meeting the Dietary Reference Intake (DRI) was determined following analysis with the US nutrient database.
  
  
  RESULTS
  Twenty-five per cent of 2411 foods deemed most likely to differ in nutrient profile were subsequently modified for folate, 11% for vitamin D, 10% for calcium and riboflavin, and between 7 and 10% for the remaining nutrients of interest. Misclassification with respect to meeting the DRI varied but was highest for folate (7%) and vitamin A (7%) among men, and for vitamin D (7%) among women over 50 years of age.
  
  
  CONCLUSIONS
  Errors in nutrient intake estimates owing to differences in food fortification between the USA and Canada can be reduced in Canadian populations by using nutrient databases that reflect Canadian fortification practices.
authors.affiliation: Division of Population Health and Information, Alberta Cancer Board, 1331-29 Street NW, Calgary, Alberta, Canada, T2N 4N2. ilona.csizmadi@cancerboard.ab.ca
authors.forename: Ilona
authors.initials: I
authors.lastname: Csizmadi
authors.forename: Lisa
authors.initials: L
authors.lastname: Kahle
authors.forename: Ruth
authors.initials: R
authors.lastname: Ullman
authors.forename: Ursula
authors.initials: U
authors.lastname: Dawe
authors.forename: Thea Palmer
authors.initials: TP
authors.lastname: Zimmerman
authors.forename: Christine M
authors.initials: CM
authors.lastname: Friedenreich
authors.forename: Heather
authors.initials: H
authors.lastname: Bryant
authors.forename: Amy F
authors.initials: AF
authors.lastname: Subar
mesh_terms: D000328:Adult; D000368:Aged; D002170:Canada; D016208:Databases, Factual; D005247:Feeding Behavior; D005260:Female; D005502:Food / Q000145:classification; D005504:Food Analysis; D005523:Food Supply; D005527:Food, Fortified; D006801:Humans; D008297:Male; D008875:Middle Aged; D008903:Minerals / Q000032:analysis*; D018673:Nutrition Policy; D009749:Nutrition Surveys; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires / Q000592:standards*; D014481:United States; D014815:Vitamins / Q000032:analysis*
chemical_list: D008903:Minerals; D014815:Vitamins