title: Risk of breast cancer after onset of type 2 diabetes: evidence of detection bias in postmenopausal women.
abstract: OBJECTIVE
  To examine the risk of breast cancer in pre- and postmenopausal women with type 2 diabetes (T2D).
  
  
  METHODS
  This was a population-based retrospective cohort study. Cox regression, stratified by pre- (<55 years) and postmenopausal (≥55 years) status, was used to estimate hazard ratios (HRs) for breast cancer, during earlier (0-3 months) and later (3 months to 10 years) time windows after diabetes index date.
  
  
  RESULTS
  Compared with women without T2D, HRs for breast cancer were 0.95 (95% CI 0.48-1.86; P = 0.88) and 1.31 (0.92-1.86; P = 0.14) in pre- and postmenopausal women with T2D, respectively, in the early time window, and 0.92 (0.75-1.13; P = 0.45) and 1.00 (0.90-1.11; P = 0.93) in pre- and postmenopausal women with T2D, respectively, in the later time window.
  
  
  CONCLUSIONS
  We observed a trend toward an increased risk of breast cancer in postmenopausal women with T2D, but only in the time period immediately after diabetes index date.
authors.affiliation: Department of Public Health Sciences, School of Public Health, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Samantha L
authors.initials: SL
authors.lastname: Bowker
authors.forename: Kathryn
authors.initials: K
authors.lastname: Richardson
authors.forename: Carlo A
authors.initials: CA
authors.lastname: Marra
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Johnson
mesh_terms: D000328:Adult; D015982:Bias; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000209:etiology; D001955:British Columbia / Q000453:epidemiology; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D017698:Postmenopause; D012189:Retrospective Studies; D012306:Risk; D018570:Risk Assessment