Table 1.
Risk factors | Significance | Reference |
---|---|---|
Family history of breast cancer | Increased risk of PABC ≤ 2 years postpartum (HR 3.28, P = 0.001) | [12] |
Genetic predisposition | BRCA1/2 carriers in PABC (25 vs. 11.5%, P = 0.034) | [12, 58] |
Age at first pregnancy > 30 years old |
5.3% increased risk of PABC per each year postponing pregnancy after 25 years of age | [59] |
No long-term BC protection from 1st pregnancy after age 35 years | [60] | |
Early age at menarche | Increased risk of PABC with early age at menarche (< 13 vs. ≥ 13 years) (HR 2.165, P < 0.001) | [4] |
Little-to-no breastfeeding | 4.3% decreased lifetime risk of BC by each 12 months of breastfeeding (P < 0.0001) | [61] |
Decreased risk of BC with breastfeeding > 12 months (HR 0.74, P < 0.001) | [62] | |
Overweight | Overweight women are at higher risk of PABC (HR 1.427, P = 0.011) | [4] |