Relative risk
Advanced age >10
Genes, family history, personal history
BRCA1/2 mutation 5-10
Breast cancer in first-degree relative 2
Previous atypical hyperplasia 4-5
Previous breast cancer >4
Breastfeeding for 12 months 0.96
One birth 0.93
Two births 0.84
Menstrual/reproductive history
Menarche before 11 years 3
Menopause after 54 years 2
First child after 30 1.2-1.4
First child after age 40 3
Current use of HRT 1.3-1.6
Current use of oral contraceptive 1.2
OtherLiving in a developed country (?oestrogen exposure) 5
High breast density on mammogram (?oestrogen exposure) >5
Abnormal exposure to ionising radiation 3
‘Lifestyle’
High socioeconomic status 2
High postmenopausal BMI 2
High premenopausal BMI <1
One alcoholic drink daily 1.07
Lancet 2005; 265: 1727-1741. Cancer 2004; 101:353-62.
