Table 3.

Association between cause of menopause and risk of breast cancer

ExposureControls (n = 2,854)Cases (n = 2,854)OR (95%CI)aP
Menopausal
 No, n (%)2,361 (82.7)2,446 (85.7)1.00 (reference)
 Yes, n (%)493 (17.3)408 (14.3)0.65 (0.53–0.79)<0.0001
Cause of menopause, n (%)
 Natural260 (53)262 (64)0.81 (0.62–1.07)0.14
 Medication-induced8 (1.6)12 (3)1.38 (0.56–3.40)0.48
 Surgical (i.e., oophorectomy)213 (43)123 (30)0.52 (0.40–0.66)<0.0001
 Radiation-induced4 (0.8)2 (1)0.48 (0.09–2.64)0.40
 Other/unknown8 (1.6)9 (2)1.05 (0.44–2.72)0.93
  • aEstimates are univariate ORs.