Table 2.

Breast cancer-specific survival by breast density and mode of detection

	Person years	N totala	N breast cancer deaths (%)	HR adjusted for age (95% CI)b	P-value	HR adjusted for age and mode of detection (95% CI)b	P-value
Overall
Dense	9418	777	173 (22.3)	0.94 (0.77–1.15)	0.58	0.84 (0.68–1.03)	0.09
Fatty	14,495	1456	306 (21.0)	1.00 (Ref.)		1.00 (Ref.)
Screen-detected + Interval cancer ≤ 24 m
Dense	7424	595	115 (19.3)	1.01 (0.78–1.31)	0.91
Fatty	10,995	995	162 (16.3)	1.00 (Ref.)
Screen-detected cancer
Dense	4329	340	44 (12.9)	0.77 (0.53–1.11)	0.16
Fatty	8589	760	105 (13.8)	1.00 (Ref.)
Interval cancer ≤ 24 m
Dense	3095	255	71 (27.8)	1.07 (0.74–1.56)	0.72
Fatty	2406	235	57 (24.3)	1.00 (Ref.)
Interval cancer > 24 m
Dense	1433	133	41 (30.8)	0.80 (0.53–1.20)	0.29
Fatty	2334	290	86 (29.7)	1.00 (Ref.)
Non-participant cancer
Dense	562	49	17 (34.7)	0.72 (0.40–1.31)	0.29
Fatty	1166	171	58 (33.9)	1.00 (Ref.)

^a Follow-up time of several participants was censored before the first death occurred in the stratum. Overall: n = 4; Screen-detected+Interval cancer ≤24 m: n = 8; Screen-detected cancer: n = 5; Interval cancer ≤24 m: n = 4; Interval cancer > 24 m: n = 1; Non-participant cancer: n = 1