Selected characteristics of the study subjects
| Case/controla | ORb (95% CI) | |
|---|---|---|
| Menopausal status | ||
| Premenopausal | 164 /204 | 1.0 |
| Postmenopausal | 319 /278 | 0.73 (0.42–1.27) |
| Age at menarche | ||
| <13 | 98 /101 | 1.0 |
| 13–14 | 219 /251 | 0.82 (0.59–1.16) |
| ≥15 | 150 /127 | 0.99 (0.68–1.46) |
| Age at FFTP | ||
| Nulliparous | 102 /57 | 1.0 |
| ≤25 | 237 /263 | 0.55 (0.38–0.81) |
| 26–30 | 94 /122 | 0.44 (0.29–0.69) |
| ≥31 | 47 /40 | 0.64 (0.36–1.12) |
| Number of full-term pregnancies | ||
| Nulliparous | 102 /57 | 1.0 |
| 1 | 68 /64 | 0.59 (0.36–0.98) |
| 2 | 141 /181 | 0.50 (0.33–0.76) |
| 3+ | 171 /180 | 0.54 (0.36–0.80) |
| Use of oral contraceptives | ||
| Never | 313 /243 | 1.0 |
| Ever | 164 /239 | 0.66 (0.48–0.91) |
| Postmenopausal use of estrogen | ||
| Never | 221 /164 | 1.0 |
| Ever | 91 /114 | 0.82 (0.58–1.16) |
| WHR | ||
| ≤0.91 | 187 /236 | 1.0 |
| >0.91 | 291 /243 | 1.38 (1.06–1.81) |
| BMI | ||
| ≤25.4 | 208 /240 | 1.0 |
| >25.4 | 260 /239 | 1.22 (0.92–1.62) |
| First-degree family history of breast cancer | ||
| No | 424 /459 | 1.0 |
| Yes | 54 /22 | 2.53 (1.48–4.31) |
| History of benign breast disease | ||
| No | 296 /313 | 1.0 |
| Yes | 180 /167 | 1.33 (1.01–1.75) |
| Educationc | ||
| Low | 292 /277 | 1.0 |
| Medium | 127 /135 | 1.11 (0.81–1.52) |
| High | 62 /69 | 1.19 (0.78–1.80) |
| Current alcohol intake | ||
| Never | 271 /206 | 1.0 |
| Once a month or less | 134 /187 | 0.74 (0.54–1.01) |
| Daily–weekly | 75 /89 | 0.87 (0.59–1.29) |
| Smoking habits | ||
| Never | 363 /351 | 1.0 |
| Ex-smoker | 52 /67 | 0.94 (0.62–1.41) |
| Current smoker | 64 /64 | 1.34 (0.87–1.93) |
a Total number of cases and controls does not correspond because of missing values.
b Adjusted for age.
c Low: none or primary school; medium: junior high school, college or corresponding; high: senior high school, trade school, or university.