Skip to main content

Table 2 Relationship between reproductive factors and breast cancer

From: Reproductive risk factors in breast cancer and genetic hormonal pathways: a gene-environment interaction in the MCC-Spain project

Reproductive factor Category OR (95% CI) p value
Age at menarche > 12 years 1 (reference)
≤ 12 years 0.95 (0.79–1.13) 0.55
Number of deliveries 0 1 (reference)
1–2 0.58 (0.38–0.90) 0.01
> 2 0.43 (0.27–0.68) < 0.001
Age at first deliverya < 20 years 1.65 (1.00–2.75) 0.05
20–24 years 1.06 (0.83–1.34) 0.65
25–29 years 1 (reference)
30–34 years 0.93 (0.70–1.23) 0.60
≥ v35 years 1.11 (0.73–1.69) 0.63
Age at menopauseb < 50 years 0.77 (0.62–0.96) 0.02
≥ 50 years 1 (reference)
Use of hormonal contraceptives No 1 (reference)
Yes 0.81 (0.67–0.97) 0.02
Use of hormone replacement therapyb No 1 (reference)
Yes 1.00 (0.95–1.06) 0.89
  1. Odds ratios (OR) adjusted for propensity score, menopausal status and mutually adjusted for the remaining variables in the table
  2. aOdds ratio estimated only in parous women
  3. bOdds ratio estimated only in postmenopausal women