Table 2.
Female hormone use in relation to breast cancer subtypes, postmenopausal women age ≥40 y
| ER+ | ER- | ||||||
|---|---|---|---|---|---|---|---|
| Female hormone use | Control patients | Case patients | OR (95% CI)* | OR (95% CI)† | Case patients | OR (95% CI)* | OR (95% CI)† |
| Never used‡ | 3509 | 649 | 1.00 (referent) | 1.00 (referent) | 300 | 1.00 (referent) | 1.00 (referent) |
| Estrogen alone | |||||||
| Ever use | 2318 | 322 | 1.03 (0.89 to 1.21) | 1.07 (0.89 to 1.28) | 153 | 1.00 (0.80 to 1.24) | 1.10 (0.85 to 1.42) |
| Duration of use, y | |||||||
| <5 | 1397 | 190 | 1.04 (0.86 to 1.25) | 1.05 (0.86 to 1.28) | 86 | 0.95 (0.73 to 1.23) | 1.01 (0.76 to 1.34) |
| 5–9 | 329 | 45 | 1.01 (0.72 to 1.41) | 1.07 (0.74 to 1.54) | 32 | 1.29 (0.86 to 1.92) | 1.51 (0.96 to 2.36) |
| ≥10 | 499 | 77 | 1.06 (0.82 to 1.39) | 1.18 (0.87 to 1.61) | 28 | 0.85 (0.56 to 1.28) | 1.03 (0.65 to 1.65) |
| Time since last use, y | |||||||
| <5 | 1200 | 144 | 1.01 (0.82 to 1.23) | 1.05 (0.82 to 1.35) | 90 | 1.03 (0.78 to 1.36) | 1.15 (0.83 to 1.58) |
| 5–9 | 332 | 51 | 1.16 (0.84 to 1.59) | 1.14 (0.81 to 1.59) | 22 | 1.09 (0.69 to 1.72) | 1.15 (0.71 to 1.86) |
| ≥10 | 714 | 115 | 1.01 (0.80 to 1.27) | 1.05 (0.82 to 1.34) | 37 | 0.90 (0.62 to 1.31) | 1.00 (0.68 to 1.48) |
| Estrogen plus progestin | |||||||
| Ever use | 1,293 | 235 | 1.54 (1.29 to 1.83) | 1.50 (1.25 to 1.79) | 86 | 1.13 (0.87 to 1.47) | 1.09 (0.83 to 1.43) |
| Duration of use, y | |||||||
| <5 | 893 | 153 | 1.45 (1.18 to 1.78) | 1.42 (1.15 to 1.74) | 59 | 1.10 (0.81 to 1.49) | 1.06 (0.78 to 1.45) |
| 5–9 | 174 | 36 | 1.84 (1.25 to 2.69) | 1.77 (1.20 to 2.62) | 15 | 1.45 (0.83 to 2.53) | 1.39 (0.79 to 2.45) |
| ≥10 | 117 | 28 | 1.81 (1.17 to 2.79) | 1.75 (1.13 to 2.73) | 4 | 0.65 (0.24 to 1.79) | 0.62 (0.22 to 1.71) |
| Time since last use, y | |||||||
| <5 | 634 | 108 | 1.61 (1.27 to 2.06) | 1.55 (1.21 to 1.99) | 46 | 1.12 (0.80 to 1.58) | 1.04 (0.73 to 1.47) |
| 5–9 | 323 | 61 | 1.84 (1.36 to 2.49) | 1.80 (1.32 to 2.45) | 15 | 0.94 (0.54 to 1.61) | 0.93 (0.54 to 1.61) |
| ≥10 | 403 | 61 | 1.37 (1.02 to 1.84) | 1.34 (0.99 to 1.82) | 18 | 1.09 (0.66 to 1.80) | 1.11 (0.67 to 1.86) |
* Adjusted for age, study, year, and geographic region. CI = confidence interval; ER = estrogen receptor; OR = odds ratio.
† Adjusted for age, study, year, geographic region, education, parity, age at first birth, age at menopause, type of menopause, age at menarche, body mass index, oral contraceptive use, family history of breast cancer, alcohol use, and smoking.
‡ Never used estrogen alone or estrogen plus progestin.