Table 3.

Incidence-based mortality studies for the evaluation of mammography screening effectiveness in Denmark and in Norway.

	Years included in study	Year of screening introduction in screening areas	Age groups	BC mortality rate in the pre-screening period (historical control)	BC mortality rate in the screening period	Ratio of BC mortality rates, screening versus pre-screening perioda	Ratio of BC mortality rates, screening versus non-screening areasa
Screening areas				No screening	Screening
Denmark, Olsen et al. 2005 [28]	1981 to 2001	1991	50 to 79	69	52	0.75	0.74
Norway, Kalager et al. 2010 [33]	1986 to 2005	1996	50 to 84	33	24	0.73	0.9
Norway, Olsen et al. 2012 [34]	1990 to 2008	1996	50 to 84	35	27	0.77	0.91
Comparison (non-screening) areas				No screening	No screening
Denmark, Olsen et al. 2005 [28]	1981 to 2001	-	50 to 79	52	53	1.02	reference
Norway, Kalager et al. 2010 [33]	1986 to 2005	-	50 to 84	31	25	0.81	reference
Norway, Olsen et al. 2012 [34]	1990 to 2008	-	50 to 84	39	33	0.85	reference

Figures in the table are breast cancer mortality rates per 100,000 women ages 50 to 79 in Denmark and 50 to 84 in Norway. ^aRate ratios may slightly differ from those of the original publications reported in Table 2 due to rounding and absence of statistical modelling. BC: breast cancer; NR: not reported.