Table 2.
Multivariate relative risk estimates for breast cancer among women aged 40 + in the EPIC-Germany study for variables in BCRAT and BCRmod using imputed datasets
| BCRmod-risk factors | Relative risks (95% confidence intervals) |
|
|---|---|---|
| EPIC (40 +) | BCRmod | |
| Body mass index (BMI) | ||
| < 25 kg/m2 | 1.0 (referent) | 1.0 (referent) |
| Per category increase | 1.00 (0.92–1.10) | 1.11 (1.07–1.16) |
| Estrogen plus progestin | ||
| No HRT use | 1.0 (referent) | 1.0 (referent) |
| Per category increase | 1.50 (1.29–1.75) | 1.53 (1.37–1.70) |
| Other HRT use | ||
| No | 1.0 (referent) | 1.0 (referent) |
| Yes | 1.58 (1.22–2.04) | 1.07 (0.98–1.17) |
| Age at first live birth | ||
| < 25 years | 1.0 (referent) | 1.0 (referent) |
| Per category increase | 1.02 (0.91–1.15) | 1.14 (1.08–1.20) |
| Parity | ||
| 1+ children | 1.0 (referent) | 1.0 (referent) |
| Nulliparous | 1.03 (0.83–1.28) | 1.31 (1.13–1.52) |
| Age at menopause | ||
| < 50 | 1.0 (referent) | 1.0 (referent) |
| Per category increase | 1.03 (0.87–1.23) | 1.20 (1.12–1.29) |
| Premenopausal | 1.35 (0.97–1.88) | 1.54 (1.32–1.80) |
| Benign breast disease/biopsy | ||
| No | 1.0 (referent) | 1.0 (referent) |
| Yes | 1.76 (1.33–2.35) | 1.34 (1.24–1.44) |
| Family history of breast or ovarian cancer | ||
| No | 1.0 (referent) | 1.0 (referent) |
| Yes | 1.64 (1.26–2.13) | 1.34 (1.22–1.47) |
| Alcohol | ||
| 0 drinks per day | 1.0 (referent) | 1.0 (referent) |
| Per category increase | 1.14 (0.93–1.39) | 1.06 (1.00–1.12) |
| BCRAT-risk factors | Relative risks (95% confidence intervals) |
|
| EPIC (40 +) | BCRAT | |
| Age at menarche | ||
| 7–11 | 0.92 (0.71–1.19) | 1.207 |
| 12–13 | 0.99 (0.85–1.16) | 1.099 |
| 14+ | 1.0 (referent) | 1.0 (referent) |
| Age 1st FTP * BC-fam. history | ||
| < 20, and none | 1.0 (referent) | 1.0 (referent) |
| < 20, and (≥) 1 1st deg. relative with breast cancer | 1.95 (0.88–4.31) | 2.607 |
| ≥ 2 1st deg. relative with breast cancer | 6.789 | |
| 20–24, and none | 1.07 (0.80–1.44) | 1.24 |
| 20–24, and (≥) 1 1st deg. relative with breast cancer | 1.77 (1.10–2.86) | 2.681 |
| ≥ 2 1st deg. relative with breast cancer | 5.775 | |
| 25–29 or nullip., and none | 1.06 (0.79–1.43) | 1.548 |
| 25–29 or nullip., and (≥) 1 1st deg. relative with bc | 1.88 (1.18–3.00) | 2.756 |
| ≥ 2 1st deg. relative with breast cancer | 4.907 | |
| 30 + , and none | 1.20 (0.84–1.72) | 1.927 |
| 30 + , and (≥) 1 1st deg. relative with breast cancer | 1.19 (0.50–2.83) | 2.834 |
| ≥ 2 1st deg. relative with breast cancer | 4.169 | |
| History of benign breast disease, used as | ||
| (≥) 1 biopsy (in women under 50) | 1.85 (1.23–2.78) | 1.698 |
| ≥ 2 biopsies | 2.882 | |
| (≥) 1 biopsy (in women 50 +) | 1.80 (1.31–2.48) | 1.273 |
| ≥ 2 biopsies | 1.620 | |
Categories for variables fitted with a trend are given below the table. The baseline hazard for EPIC-Germany was stratified by center and by age </>50 years for BCRmod, and only by center for BCRAT
Models were fit with baseline stratified by center. All variables are coded so that the lowest risk category is the reference category. Categories for: BMI: < 25, 25– < 30, 30– < 35, and 35 + ; menopausal hormone therapy use: 0, 1–9, and 10 + years; estrogen plus progestin HRT use: 0, 1–9, and 10+ years; other/unknown HRT use: no, yes; age at first birth: < 25, 25–29, and 30+ years; age at menopause: < 50, 50–54, 55+years, missing; benign breast diseases/biopsy: no, yes, missing; alcohol consumption: 0, < 1, 1+ drink/day, age at menarche: 14 + , 12–13, 7–11