Table 1.

Key patient and imaging characteristics of the study cohort (200 patients including 100 breast cancer cases and 100 matched controls). Each patient has four prior mammogram examinations.

	Cases (N=100) n (%)	Controls (N=100) n (%)
Patient/Imaging characteristics
Age (years): mean ± SD (range)	61.8 ± 9.0 (39–88)	61.0 ± 9.6 (41–88)
Time frame between 4th prior and current (years): mean ± SD (range)	4.7 ± 0.8 (4–7)	4.7 ± 1.0 (4–8)
Time frame between 1st prior and current (months): mean (range)	15 (7–23)	16 (12–23)
Menopausal status
Premenopausal	10 (10%)	20 (20%)
Postmenopausal	81 (81%)	76 (76%)
Hysterectomy	3 (3%)	3 (3%)
Uncertain	6 (6%)	1 (1%)
Family history of breast cancer
No family history	40 (40%)	54 (54%)
With family history	59 (59%)	46 (46%)
Unknown	1 (1%)	0 (0%)
Mammographic density (visual BI-RADS density categories)
Fatty	7 (7%)	9 (9%)
Scattered fibroglandular tissue	42 (42%)	37 (37%)
Heterogeneously dense	50 (50%)	51 (51%)
Extremely dense	1 (1%)	2 (2%)