Table 3.
Use of estrogen plus progestin in relation to ER+ breast cancer, postmenopausal women age ≥40 y, stratified by body mass index, age, and type of menopause
| Characteristic | Never used* | Ever used | P† | ||
|---|---|---|---|---|---|
| Case patients/ Control patients | OR (95% CI) ‡ | Case patients/ Control patients | OR (95% CI) ‡ | ||
| Body mass index, kg/m2 | .17 | ||||
| <25 | 98/721 | 1.00 (referent) | 62/317 | 1.91 (1.29 to 2.83) | |
| 25–29 | 192/1179 | 1.00 (referent) | 83/448 | 1.69 (0.83 to 1.64) | |
| ≥30 | 326/1501 | 1.00 (referent) | 86/501 | 1.24 (0.93 to 1.65) | |
| Age, y | .58 | ||||
| 40–59 | 218/1147 | 1.00 (referent) | 75/510 | 1.29 (0.93 to 1.78) | |
| 60–69 | 228/1199 | 1.00 (referent) | 101/516 | 1.60 (1.19 to 2.15) | |
| ≥70 | 203/1163 | 1.00 (referent) | 59/267 | 1.72 (1.22 to 2.44) | |
| Type of menopause | |||||
| Natural | 521/2779 | 1.00 (referent) | 178/942 | 1.55 (1.26 to 1.91) | |
| Bilateral oophorectomy | 77/510 | 1.00 (referent) | 48/302 | 1.51 (0.98 to 2.31) | .82 |
* Never used estrogen alone or estrogen plus progestin. CI = confidence interval; OR = odds ratio.
† Two-sided P value for interaction.
‡ 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.