Table 1.
Risk factors associated with CBC in the final relative risk model. The overall p-value for the model is < 0.0001.
| Risk factors | Categories | Relative Risk (95% CI) | p-value | No. of CBC cases (n=1,921) | No. of controls (n=5,763) |
|---|---|---|---|---|---|
| Age at first diagnosis (AFDX) | <30 | 2.19 (1.18, 4.08) | 0.01 | 18 | 24 |
| 30–39 | 1.31 (1.04, 1.65) | 0.02 | 121 | 267 | |
| 40+ | 1 | 1782 | 5472 | ||
| Anti-estrogen therapy (AEST) | Yes | 0.78 (0.69, 0.88) | 0.00 | 495 | 1837 |
| Unknown | 0.95 (0.77, 1.17) | 0.63 | 141 | 427 | |
| No | 1 | 1285 | 3499 | ||
| Family History (FHIST) | Yes | 1.57 (1.32, 1.87) | 0.00 | 245 | 524 |
| Unknown | 1.20 (1.02, 1.41) | 0.03 | 920 | 2783 | |
| No | 1 | 756 | 2456 | ||
| High risk pre-neoplasia status (HRPN) | Yes | 1.57 (1.09, 2.26) | 0.01 | 50 | 85 |
| No/Unknown | 1 | 1871 | 5678 | ||
| Breast density (DENS) | Extremely dense | 2.02 (1.20, 3.39) | 0.01 | 94 | 211 |
| Heterogeneously dense | 1.70 (1.07, 2.72) | 0.03 | 405 | 1097 | |
| Scattered | 1.53 (0.95, 2.45) | 0.08 | 326 | 1017 | |
| Unknown | 1.48 (0.93, 2.36) | 0.10 | 1073 | 3328 | |
| Almost entirely fat | 1 | 23 | 110 | ||
| ER status (ER) | Negative | 1.14 (0.97, 1.33) | 0.11 | 617 | 797 |
| Unknown | 0.84 (0.73, 0.96) | 0.01 | 307 | 1771 | |
| Positive | 1 | 997 | 3195 | ||
| First Breast Cancer type (FTYP) | Pure DCIS | 1.66 (1.42, 1.93) | 0.00 | 461 | 996 |
| Mixed Invasive-DCIS | 1.36 (1.10, 1.68) | 0.00 | 149 | 357 | |
| Pure Invasive | 1 | 1311 | 4410 | ||
| Age at first birth (AFB) | 30–39 | 1.30 (1.00, 1.69) | 0.05 | 96 | 220 |
| 40+ | 3.71 (1.58, 8.71) | 0.00 | 12 | 10 | |
| Unknown | 0.97 (0.83, 1.14) | 0.72 | 1221 | 3749 | |
| <30/Nulliparous | 1 | 592 | 1784 |