title: Breast cancer mortality in Copenhagen after introduction of mammography screening: cohort study.
abstract: OBJECTIVE
  To evaluate the effect on breast cancer mortality during the first 10 years of the mammography service screening programme that was introduced in Copenhagen in 1991.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  The mammography service screening programme in Copenhagen, Denmark.
  
  
  METHODS
  All women ever invited to mammography screening in the first 10 years of the programme. Historical, national, and historical national control groups were used.
  
  
  METHODS
  The main outcome measure was breast cancer mortality. We compared breast cancer mortality in the study group with rates in the control groups, adjusting for age, time period, and region.
  
  
  RESULTS
  Breast cancer mortality in the screening period was reduced by 25% (relative risk 0.75, 95% confidence interval 0.63 to 0.89) compared with what we would expect in the absence of screening. For women actually participating in screening, breast cancer mortality was reduced by 37%.
  
  
  CONCLUSIONS
  In the Copenhagen programme, breast cancer mortality was reduced without severe negative side effects for the participants.
authors.affiliation: Institute of Public Health, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark. a.h.olsen@pubhealth.ku.dk
authors.forename: Anne Helene
authors.initials: AH
authors.lastname: Olsen
authors.forename: Sisse H
authors.initials: SH
authors.lastname: Njor
authors.forename: Ilse
authors.initials: I
authors.lastname: Vejborg
authors.forename: Walter
authors.initials: W
authors.lastname: Schwartz
authors.forename: Peter
authors.initials: P
authors.lastname: Dalgaard
authors.forename: Maj-Britt
authors.initials: MB
authors.lastname: Jensen
authors.forename: Ulla Brix
authors.initials: UB
authors.lastname: Tange
authors.forename: Mogens
authors.initials: M
authors.lastname: Blichert-Toft
authors.forename: Fritz
authors.initials: F
authors.lastname: Rank
authors.forename: Henning
authors.initials: H
authors.lastname: Mouridsen
authors.forename: Elsebeth
authors.initials: E
authors.lastname: Lynge
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000401:mortality* / Q000517:prevention & control; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008327:Mammography / Q000401:mortality*; D008403:Mass Screening / Q000379:methods / Q000401:mortality*; D008875:Middle Aged; D012044:Regression Analysis; D012307:Risk Factors