Table 2.
Association between %MD and CBC risk categories prior to/ata diagnosis and post diagnosisb
| CBC Number (%) |
UBC Number (%) |
ORc (95% CI) | |
|---|---|---|---|
| Percent mammographic density prior to/at diagnosis | |||
| <25% | 67 (26) | 81 (30) | 0.77 (0.49, 1.21) |
| 25 to <50% | 125 (49) | 130 (48) | 1.00 |
| ≥50% | 61 (24) | 58 (22) | 1.17 (0.73, 1.87) |
| p trend | 0.12 | ||
| Percent mammographic density post diagnosis | |||
| <25% | 129 (39) | 181 (48) | 0.69 (0.49, 0.98) |
| 25 to <50% | 152 (46) | 155 (41) | 1.00 |
| ≥50% | 52 (16) | 41 (11) | 1.21 (0.74, 1.99) |
| p trend | 0.03 | ||
Abbreviations: %MD percent mammographic density, CBC contralateral breast cancer, UBC unilateral breast cancer, OR odds ratio, CI confidence interval
aPior to/at diagnosis was 36 months prior up to 1 month post diagnosis
bPost diagnosis was > 6 months up to 48 months post diagnosis
cOR adjusted for study center, race (non-Hispanic white versus other), age at mammogram, menopausal status at mammogram, estimated body mass index at mammogram, age at first diagnosis, age at menarche, number of full-term pregnancies, first-degree family history of breast cancer, histologic type, stage, estrogen receptor status of first diagnosis, chemotherapy, radiation, and tamoxifen use after first diagnosis