Table 1.
Baseline characteristics of women with at least one benign breast biopsy
| Characteristic | No breast cancer, no. (n = 41459) | Breast cancer, no. (n = 1359) |
P* |
|---|---|---|---|
| Pathology from benign biopsy | <.001 | ||
| Nonproliferative | 29138 (70.3%) | 792 (58.3%) | |
| Proliferative disease without atypia | 10483 (25.3%) | 431 (31.7%) | |
| Atypical hyperplasia | 1838 (4.4%) | 136 (10.0%) | |
| Breast density† | <.001 | ||
| Almost entirely fat | 1920 (4.6%) | 39 (2.9%) | |
| Scattered fibroglandular densities | 15892 (38.3%) | 436 (32.1%) | |
| Heterogeneously dense | 18424 (44.4%) | 667 (49.1%) | |
| Extremely dense | 5223 (12.6%) | 217 (16.0%) | |
| Age at biopsy, y | <.001 | ||
| 30–39 | 4928 (11.9%) | 58 (4.3%) | |
| 40–49 | 14987 (36.1%) | 413 (30.4%) | |
| 50–59 | 11340 (27.4%) | 382 (28.1%) | |
| 60–69 | 5942 (14.3%) | 291 (21.4%) | |
| 70–79 | 3361 (8.1%) | 169 (12.4%) | |
| ≥80 | 901 (2.2%) | 46 (3.4%) | |
| Race or ethnicity | .008 | ||
| White, non-Hispanic | 32319 (78.0%) | 1098 (80.8%) | |
| Black, non-Hispanic | 2749 (6.6%) | 78 (5.7%) | |
| Asian | 571 (1.4%) | 19 (1.4%) | |
| Hispanic | 2230 (5.4%) | 59 (4.3%) | |
| Other/mixed | 847 (2.0%) | 11 (0.8%) | |
| Unknown/not reported | 2743 (6.6%) | 94 (6.9%) | |
| Family history of breast cancer in first-degree relative | 5879 (16.9%) | 272 (24.3%) | <.001 |
| Postmenopausal | 18134 (52.2%) | 780 (66.7%) | <.001 |
| Current hormone therapy use | 7920 (20.8%) | 355 (29.3%) | <.001 |
| Nulliparous | 3576 (14.3%) | 143 (15.3%) | .40 |
| Age at first live birth ≥30 y (if parous) | 2596 (12.9%) | 103 (13.8%) | .52 |
| Body mass index, kg/m2 | .66 | ||
| <18.5 | 479 (1.9%) | 14 (1.6%) | |
| 18.5 to <25 | 11144 (44.3%) | 387 (43.8%) | |
| 25 to <30 | 7065 (28.1%) | 244 (27.6%) | |
| 30 to <35 | 3826 (15.2%) | 150 (17.0%) | |
| ≥35 | 2619 (10.4%) | 89 (10.1%) |
* Two-sided P value using the χ2 test.
† Using the Breast Imaging Reporting and Data System (BI-RADS) density categories: 1 = almost entirely fat (low density); 2 = scattered fibroglandular densities (average density); 3 = heterogeneously dense (high density); 4 = extremely dense (very high density).