Table 2 Relative risks of total breast cancers based on Singapore Breast Cancer Screening Project cohort by risk factors in Gail model
| Risk factors | Based on SBCSP (95% CI) | Gail model: BCDDP (95% CI) |
|---|---|---|
| Age at menarche, years | ||
| ≥14 | 1.00 (referent) | 1.00 (referent) |
| 12-13 | 1.39 | 1.10 |
| < 12 | 1.95 | 1.21 |
|
Any breast biopsy Age at screening: ≥50 years | ||
| No | 1.00 (referent) | 1.00 (referent) |
| Yes | 1.97 | 1.28a |
|
Number of affected first-degree relatives Age at first live birth: < 20 years | ||
| 0 | 1.00 (referent) | 1.00 (referent) |
| 1 | 3.61 | 2.61 |
| > 1 | 13.04 | 6.80 |
|
Number of affected first-degree relatives Age at first live birth: 20-24 years | ||
| 0 | 1.33 | 1.24 |
| 1 | 4.14 | 2.68 |
| > 1 | 12.91 | 5.78 |
|
Number of affected first-degree relatives Age at first live birth: 25-29 years or nulliparous | ||
| 0 | 1.76 | 1.55 |
| 1 | 4.75 | 2.76 |
| > 1 | 12.79 | 4.91 |
|
Number of affected first-degree relatives Age at first live birth: > 30 years | ||
| 0 | 2.34 | 1.93 |
| 1 | 5.44 | 2.83 |
| > 1 | 12.67 | 4.17 |