Estrogen + progestin HRT |
no HRT |
1.25** (1.07–1.46) |
|
33
|
Birth |
one child less |
0.93* (0.91–0.97 |
risk reduction per child |
25
|
12 monthsʼ breastfeeding |
12 months less breastfeeding |
0.96* (0.94–0.97) |
risk reduction per 12 monthsʼ breastfeeding |
25
|
First-degree relative with breast cancer |
no first-degree relative with breast cancer |
1.78***–2.61*** (CI not reported) |
figures from the BCDDP and the Nursesʼ Health Study |
118
|
History of breast biopsy |
no history of breast biopsy |
1.9*** (1.2–2.9) |
|
119
|
History of atypical breast biopsy |
no history of atypical breast biopsy |
5.3*** (3.1–8.8) |
|
119
|
Age at menarche > 14 |
age at menarche < 12 |
*0.77 (CI not reported) |
|
120, 121, 122
|
Age at menopause < 45 |
age at menopause > 54 |
2.0* (CI not reported) |
|
120, 121, 122
|