title: Dietary patterns and breast cancer risk: a study in 2 cohorts.
abstract: BACKGROUND
  Evidence for a role of dietary risk factors in the cause of breast cancer has been inconsistent. The evaluation of overall dietary patterns instead of foods in isolation may better reflect the nature of true dietary exposure in a population.
  
  
  OBJECTIVE
  We used 2 cohort studies to identify and confirm associations between dietary patterns and breast cancer risk.
  
  
  METHODS
  Dietary patterns were derived by using a principal components factor analysis in 1097 breast cancer cases and an age-stratified subcohort of 3320 women sampled from 39,532 female participants in the Canadian Study of Diet, Lifestyle and Health (CSDLH). We conducted a confirmatory factor analysis in 49,410 subjects in the National Breast Screening Study (NBSS) in whom 3659 cases of incident breast cancer developed. Cox regression models were used to estimate HRs for the association between derived dietary factors and risk of breast cancer in both cohorts.
  
  
  RESULTS
  The following 3 dietary factors were identified from the CSDLH: healthy, ethnic, and meat and potatoes. In the CSDLH, the healthy dietary pattern was associated with reduced risk of breast cancer (HR for high compared with low quintiles: 0.73; 95% CI: 0.58, 0.91; P-trend = 0.001), and the meat and potatoes dietary pattern was associated with increased risk in postmenopausal women only (HR for high compared with low quintiles: 1.26; 95% CI: 0.92, 1.73; P-trend = 0.043). In the NBSS, the association between the meat and potatoes pattern and postmenopausal breast cancer risk was confirmed (HR: 1.31; 95% CI: 0.98, 1.76; P-trend = 0.043), but there was no association between the healthy pattern and risk of breast cancer.
  
  
  CONCLUSIONS
  Adherence to a plant-based diet that limits red meat intake may be associated with reduced risk of breast cancer, particularly in postmenopausal women.
authors.affiliation: From the Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY (CC, RSK, and TER); Prevention and Cancer Control, Cancer Care Ontario, Toronto, Canada (VAK and NK); the Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (VAK and NK); the University of Alberta, Edmonton, Canada (CLS); and the Faculty of Health, University of Canberra, Canberra, Australia (CLS).
authors.forename: Chelsea
authors.initials: C
authors.lastname: Catsburg
authors.affiliation: From the Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY (CC, RSK, and TER); Prevention and Cancer Control, Cancer Care Ontario, Toronto, Canada (VAK and NK); the Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (VAK and NK); the University of Alberta, Edmonton, Canada (CLS); and the Faculty of Health, University of Canberra, Canberra, Australia (CLS).
authors.forename: Ryung S
authors.initials: RS
authors.lastname: Kim
authors.affiliation: From the Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY (CC, RSK, and TER); Prevention and Cancer Control, Cancer Care Ontario, Toronto, Canada (VAK and NK); the Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (VAK and NK); the University of Alberta, Edmonton, Canada (CLS); and the Faculty of Health, University of Canberra, Canberra, Australia (CLS).
authors.forename: Victoria A
authors.initials: VA
authors.lastname: Kirsh
authors.affiliation: From the Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY (CC, RSK, and TER); Prevention and Cancer Control, Cancer Care Ontario, Toronto, Canada (VAK and NK); the Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (VAK and NK); the University of Alberta, Edmonton, Canada (CLS); and the Faculty of Health, University of Canberra, Canberra, Australia (CLS).
authors.forename: Colin L
authors.initials: CL
authors.lastname: Soskolne
authors.affiliation: From the Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY (CC, RSK, and TER); Prevention and Cancer Control, Cancer Care Ontario, Toronto, Canada (VAK and NK); the Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (VAK and NK); the University of Alberta, Edmonton, Canada (CLS); and the Faculty of Health, University of Canberra, Canberra, Australia (CLS).
authors.forename: Nancy
authors.initials: N
authors.lastname: Kreiger
authors.affiliation: From the Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY (CC, RSK, and TER); Prevention and Cancer Control, Cancer Care Ontario, Toronto, Canada (VAK and NK); the Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (VAK and NK); the University of Alberta, Edmonton, Canada (CLS); and the Faculty of Health, University of Canberra, Canberra, Australia (CLS).
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Rohan
mesh_terms: D000368:Aged; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control*; D002170:Canada; D015331:Cohort Studies; D004032:Diet; D014676:Diet, Vegetarian; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008019:Life Style; D008460:Meat; D008875:Middle Aged; D017698:Postmenopause; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D011198:Solanum tuberosum; D011795:Surveys and Questionnaires; D014675:Vegetables
keywords: PCFA; breast cancer; cohort; dietary patterns; epidemiology