Breast cancer mortality in Copenhagen after introduction of mammography screening: cohort study.
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.
Olsen
Anne Helene
AH
Institute of Public Health, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark. a.h.olsen@pubhealth.ku.dk
Njor
Sisse H
SH
Vejborg
Ilse
I
Schwartz
Walter
W
Dalgaard
Peter
P
Jensen
Maj-Britt
MB
Tange
Ulla Brix
UB
Blichert-Toft
Mogens
M
Rank
Fritz
F
Mouridsen
Henning
H
Lynge
Elsebeth
E
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