title: Harmonization of Food-Frequency Questionnaires and Dietary Pattern Analysis in 4 Ethnically Diverse Birth Cohorts.
abstract: BACKGROUND
  Canada is an ethnically diverse nation, which introduces challenges for health care providers tasked with providing evidence-based dietary advice.
  
  
  OBJECTIVE
  We aimed to harmonize food-frequency questionnaires (FFQs) across 4 birth cohorts of ethnically diverse pregnant women to derive robust dietary patterns to investigate maternal and newborn outcomes.
  
  
  METHODS
  The NutriGen Alliance comprises 4 prospective birth cohorts and includes 4880 Canadian mother-infant pairs of predominantly white European [CHILD (Canadian Healthy Infant Longitudinal Development) and FAMILY (Family Atherosclerosis Monitoring In earLY life)], South Asian [START (SouTh Asian birth cohoRT)-Canada], or Aboriginal [ABC (Aboriginal Birth Cohort)] origins. CHILD used a multiethnic FFQ based on a previously validated instrument designed by the Fred Hutchinson Cancer Research Center, whereas FAMILY, START, and ABC used questionnaires specifically designed for use in white European, South Asian, and Aboriginal people, respectively. The serving sizes and consumption frequencies of individual food items within the 4 FFQs were harmonized and aggregated into 36 common food groups. Principal components analysis was used to identify dietary patterns that were internally validated against self-reported vegetarian status and externally validated against a modified Alternative Healthy Eating Index (mAHEI).
  
  
  RESULTS
  Three maternal dietary patterns were identified-"plant-based," "Western," and "health-conscious"-which collectively explained 29% of the total variability in eating habits observed in the NutriGen Alliance. These patterns were strongly associated with self-reported vegetarian status (OR: 3.85; 95% CI: 3.47, 4.29; r2= 0.30, P < 0.001; for a plant-based diet), and average adherence to the plant-based diet was higher in participants in the fourth quartile of the mAHEI than in the first quartile (mean difference: 46.1%; r2= 0.81, P < 0.001).
  
  
  CONCLUSIONS
  Dietary data collected by using FFQs from ethnically diverse pregnant women can be harmonized to identify common dietary patterns to investigate associations between maternal dietary intake and health outcomes.
authors.affiliation: Departments of Clinical Epidemiology and Biostatistics, rdesouz@mcmaster.ca.|Department of Nutritional Sciences and.|Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Russell J
authors.identifier: http://orcid.org/0000-0001-8945-513X
authors.initials: RJ
authors.lastname: de Souza
authors.affiliation: Medicine, and.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Zulyniak
authors.affiliation: Population Health Research Institute, Hamilton Health Sciences and McMaster University, Hamilton, Ontario, Canada.
authors.forename: Dipika
authors.initials: D
authors.lastname: Desai
authors.affiliation: Departments of Clinical Epidemiology and Biostatistics.
authors.forename: Mateen R
authors.initials: MR
authors.lastname: Shaikh
authors.affiliation: Medicine, and.
authors.forename: Natalie C
authors.initials: NC
authors.lastname: Campbell
authors.affiliation: Medicine, and.
authors.forename: Diana L
authors.initials: DL
authors.lastname: Lefebvre
authors.affiliation: Medicine, and.|Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Milan
authors.initials: M
authors.lastname: Gupta
authors.affiliation: Six Nations Health Services, Ohsweken, Ontario, Canada.
authors.forename: Julie
authors.initials: J
authors.lastname: Wilson
authors.affiliation: Pediatrics, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Gita
authors.initials: G
authors.lastname: Wahi
authors.affiliation: Pediatrics, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Atkinson
authors.affiliation: Medicine, and.
authors.forename: Koon K
authors.initials: KK
authors.lastname: Teo
authors.affiliation: Hospital for Sick Children and Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Padmaja
authors.initials: P
authors.lastname: Subbarao
authors.affiliation: Department of Pediatrics and Child Health, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Allan B
authors.initials: AB
authors.lastname: Becker
authors.affiliation: Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; and.
authors.forename: Piushkumar J
authors.initials: PJ
authors.lastname: Mandhane
authors.affiliation: British Columbia Children's Hospital and Child and Family Research Institute, Department of Pediatrics, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Stuart E
authors.initials: SE
authors.lastname: Turvey
authors.affiliation: Medicine, and.
authors.forename: Malcolm R
authors.initials: MR
authors.lastname: Sears
authors.affiliation: Departments of Clinical Epidemiology and Biostatistics.|Medicine, and.|Population Health Research Institute, Hamilton Health Sciences and McMaster University, Hamilton, Ontario, Canada.
authors.forename: Sonia S
authors.initials: SS
authors.lastname: Anand
mesh_terms: D000328:Adult; D002648:Child; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D015930:Diet Records; D005006:Ethnicity; D005190:Family; D005247:Feeding Behavior; D006801:Humans; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires
keywords: FFQ; PCA; dietary patterns; ethnicity; food frequency questionnaire; harmonization; multiethnic; principal component analysis; prospective cohort