Table 2.
Adjusted hazard ratios (HR) and 95% confidence intervals (CI) for breast cancer risk and history of benign breast disease (BBD)
| Person-years | Number of breast cancers1 | Adjusted model2 |
|
|---|---|---|---|
| HR (95% CI) | |||
| Benign breast disease (BBD) | |||
| No BBD | 128,062.0 | 592 | Reference |
| Yes BBD | 48,694.5 | 370 | 1.31 (1.14–1.50) |
| Benign breast disease (BBD) and pregnancy | |||
| No BBD, nulliparous | 34,242.6 | 116 | Reference |
| BBD before first pregnancy | 6,152.0 | 42 | 1.34 (0.93–1.94) |
| BBD in nulliparous | 8,005.7 | 55 | 1.49 (1.07–2.06) |
| BBD after first pregnancy | 32,532.6 | 256 | 1.33 (1.04–1.69) |
| No BBD, parous | 93,797.1 | 481 | 1.02 (0.82–1.27) |
| Recency of benign breast disease (BBD) | |||
| No BBD | 116,882.8 | 539 | Reference |
| 0–5 years | 642.8 | 29 | 1.31 (0.89–1.91) |
| 6–10 years | 3,142.0 | 47 | 1.12 (0.83–1.52) |
| 11–20 years | 17,013.9 | 104 | 1.30 (1.05–1.61) |
| ≥21 years | 21,697.5 | 125 | 1.35 (1.10–1.66) |
Abbreviations: HR, hazard ratio; CI, confidence interval.
1
The total number of breast cancer cases do not add up to total due to missing information on covariates.
2
All models are adjusted for full-lifetime BOADICEA risk score, race/ethnicity, and study site and stratified by birth cohort. BBD models are also adjusted for screening mammography, recency of BBD models are also adjusted for age at baseline.