Table 1.
Thebaseline characteristics of total 484 BC patients and 484 cancer-free controls.
| Variables | Cases (%) | Controls (%) | P b | OR(95%CI) |
|---|---|---|---|---|
| n = 484 | n = 484 | |||
| Age (Mean ± SD) | 48.41 ± 10.21 | 49.23 ± 10.15 | 0.211a | |
| Age at menarche (Mean ± SD) | 14.48 ± 1.82 | 14.08 ± 1.78 | 0.001a | |
| Age at menopause | ||||
| ≤50 | 352 (0.73) | 337 (0.70) | 1 | |
| >50 | 132 (0.27) | 147 (0.30) | 0.287 | 0.86 (0.65–1.14) |
| Menopausal state | ||||
| Pre-menopausal | 291 (0.60) | 283 (0.59) | 1 | |
| Post-menopausal | 193 (0.40) | 201 (0.41) | 0.601 | 0.93 (0.72–1.21) |
| No. of abortions | ||||
| ≤1 | 336 (0.69) | 330 (0.68) | 1 | |
| 2~3 | 123 (0.25) | 138 (0.29) | 0.382 | 0.87 (0.65–1.18) |
| ≥4 | 25 (0.06) | 16 (0.03) | 0.189 | 1.59 (0.80–3.16) |
| No. of pregnancy | ||||
| ≤1 | 60 (0.12) | 87 (0.18) | 1 | |
| 2 | 116 (0.24) | 156 (0.33) | 0.727 | 1.08 (0.70–1.66) |
| 3 | 132 (0.27) | 114 (0.24) | 0.019 | 1.68 (1.09–2.60) |
| ≥4 | 176 (0.37) | 127 (0.26) | 0.001 | 2.01 (1.32–3.06) |
| Breast-feeding | ||||
| No | 27 (0.06) | 42 (0.09) | 1 | |
| Yes | 457 (0.94) | 442 (0.91) | 0.063 | 1.61 (0.98–2.65) |
| Family history | ||||
| No | 462 (0.95) | 463 (0.96) | 1 | |
| Yes | 22 (0.05) | 21 (0.04) | 0.876 | 1.05 (0.57–1.94) |
| ER | ||||
| Negative | 149 (0.31) | |||
| Positive | 293 (0.61) | |||
| PR | ||||
| Negative | 188 (0.39) | |||
| Positive | 253 (0.52) | |||
| HER-2 | ||||
| Negative | 120 (0.25) | |||
| Positive | 308 (0.64) | |||
aStudent’s t test.
bTwo-sided χ2 test, P < 0.05 was considered to be statistically significant.