Table 4.
Female hormone use in relation to breast cancer subtypes, postmenopausal women age ≥40 y, stratified by time between menopause and initiation of female hormone use
| Time between menopause and initiation of female hormone use | ER+ | ER- | |||
|---|---|---|---|---|---|
| Control patients | Case patients | OR (95% CI)* | Case patients | OR (95% CI)* | |
| Never used† | 3509 | 649 | 1.00 (referent) | 300 | 1.00 (referent) |
| Estrogen alone | |||||
| <5-y interval | |||||
| Ever use | 983 | 164 | 1.14 (0.90 to 1.45) | 76 | 1.06 (0.75 to 1.49) |
| Duration of use, y | |||||
| <5 | 611 | 97 | 1.16 (0.86 to 1.48) | 36 | 0.85 (0.56 to 1.29) |
| ≥5 | 358 | 66 | 1.18 (0.84 to 1.68) | 38 | 1.45 (0.91 to 2.32) |
| Time since last use, y | |||||
| <5 | 524 | 73 | 1.01 (0.72 to 1.41) | 46 | 1.02 (0.66 to 1.58) |
| ≥5 | 457 | 90 | 1.23 (0.93 to 1.64) | 29 | 1.05 (0.67 to 1.65) |
| ≥5-y interval | |||||
| Ever use | 711 | 83 | 1.17 (0.87 to 1.56) | 40 | 1.21 (0.80 to 1.82) |
| Duration of use, y | |||||
| <5 | 468 | 56 | 1.12 (0.81 to 1.55) | 32 | 1.34 (0.87 to 2.05) |
| ≥5 | 211 | 25 | 1.38 (0.84 to 2.26) | 6 | 0.70 (0.29 to 1.69) |
| Time since last use, y | |||||
| <5 | 445 | 52 | 1.32 (0.92 to 1.91) | 23 | 1.05 (0.63 to 1.76) |
| ≥5 | 255 | 30 | 1.01 (0.66 to 1.53) | 17 | 1.56 (0.90 to 2.71) |
| Estrogen plus progestin | |||||
| <5-y interval | |||||
| Ever use | 568 | 988 | 1.43 (1.11 to 1.85) | 28 | 0.69 (0.45 to 1.05) |
| Duration of use, y | |||||
| <5 | 406 | 68 | 1.37 (1.02 to 1.84) | 19 | 0.62 (0.38 to 1.03) |
| ≥5 | 142 | 24 | 1.39 (0.87 to 2.23) | 7 | 0.79 (0.36 to 1.75) |
| Time since last use, y | |||||
| <5 | 313 | 47 | 1.33 (0.93 to 1.89) | 17 | 0.65 (0.38 to 1.11) |
| ≥5 | 254 | 51 | 1.54 (1.09 to 2.16) | 11 | 0.75 (0.39 to 1.42) |
| ≥5-y interval | |||||
| Ever use | 412 | 78 | 1.78 (1.34 to 2.37) | 23 | 1.15 (0.72 to 1.84) |
| Duration of use, y | |||||
| <5 | 116 | 58 | 1.69 (1.23 to 2.33) | 19 | 1.21 (0.73 to 2.02) |
| ≥5 | 53 | 13 | 2.18 (1.14 to 4.17) | 3 | 1.25 (0.38 to 4.14) |
| Time since last use, y | |||||
| <5 | 203 | 36 | 1.72 (1.15 to 2.55) | 13 | 1.15 (0.62 to 2.10) |
| ≥5 | 207 | 42 | 1.86 (1.28 to 2.68) | 10 | 1.16 (0.59 to 2.28) |
* 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. CI = confidence interval; OR = odds ratio.
† Never used estrogen alone or estrogen plus progestin.