Table 2

RR of breast cancer according to ever use of postmenopausal hormones

Hormone useAll womenWomen with natural menopause
CasesControlsRRa (95% CI)RRa,b (95% CI)CasesControlsRRa,b (95% CI)
Nonusers3827413211278029191
Any use147114391.14 (1.04–1.26)1.28 (1.16–1.43)6916161.32 (1.14–1.52)
Estrogen alone only100710271.07 (0.97–1.19)1.23 (1.09–1.39)3083031.11 (0.92–1.34)
Estrogen with progestin only3152861.36 (1.14–1.64)1.43 (1.18–1.74)2792451.51 (1.21–1.88)
 Progestin added (days/month)c
  <1039361.52 (0.93–2.49)1.57 (0.95–2.60)33291.69 (0.95–2.99)
  10–21901270.92 (0.68–1.23)0.96 (0.70–1.31)811061.04 (0.74–1.46)
  >211311021.48 (1.12–1.97)1.54 (1.15–2.07)115961.45 (1.06–1.99)
Both estrogen alone and estrogen with progestin1191101.17 (0.88–1.56)1.22 (0.91–1.64)81591.68 (1.15–2.46)
Progestin only30162.26 (1.17–4.34)2.09 (1.07–4.07)2393.04 (1.31–7.03)
  • a Logistic regression models conditional on age and state.

  • b RRs have been adjusted for age at menopause, type of menopause, age at first full-term pregnancy, body mass index, family history of breast cancer, education, screening mammography history, recent alcohol consumption, history of benign breast disease, age at menarche, and recent physical activity.

  • c Determined by current regimen else highest number of days/month in former users.