Table 1.

Characteristics of the study population.

	No benign breast disease N = 619,864	Benign breast disease diagnosed in a prevalent screen N = 5,049	Benign breast disease diagnosed in an incident screen N = 4,174
Age at first screen
50-54	360,020 (58.1%)	3,420 (67.7%)	2,687 (64.4%)
55-59	123,994 (20.0%)	758 (15.0%)	936 (22.4%)
60-64	100,956 (16.3%)	637 (12.6%)	499 (12.0%)
65-69	34,894 (5.6%)	234 (4.6%)	52 (1.2%)
Year of first screen
<2005	299,173 (48.3%)	2,111 (41.8%)	2,856 (68.4%)
2005–2010	167,747 (27.1%)	1,220 (24.2%)	1,038 (24.9%)
>2010	152,944 (24.7%)	1,718 (34%)	280 (6.7%)
Type of benign breast disease
No benign breast disease	619,864 (100%)	0 (0.0%)	0 (0.0%)
Non-proliferative	0 (0.0%)	3,948 (78.2%)	3,282 (78.6%)
Proliferative without atypia	0 (0.0%)	877 (17.4%)	728 (17.4%)
Proliferative with atypia	0 (0.0%)	224 (4.4%)	164 (3.9%)
Breast Cancer
No	610,680 (98.5%)	4,928 (97.6%)	4,048 (97%)
Si	9,184 (1.5%)	121 (2.4%)	126 (3.0%)