Table 1 Distribution of reproductive risk factors according to the five surrogate BC subtypes
From: Reproductive profiles and risk of breast cancer subtypes: a multi-center case-only study
|  |  | All BC subtypes N = 11,328 (100.0%) | Luminal A-like N = 5914 (52.2%) | Luminal B-like N = 1553 (13.7%) | Luminal HER2-like N = 1509 (13.3%) | HER2-like N = 841 (7.4%) | TNBC N = 1511 (13.3%) | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
N | % | N | % | N | % | N | % | N | % | N | % | ||
Age at breast cancer diagnosis, years | Mean/median | 56.0/56.0 | Â | 57.6/57.0 | Â | 56.9/57.0 | Â | 52.6/52.0 | Â | 52.9/53.0 | Â | 53.8/54.0 | Â |
<41 | 1077 | 9.5% | 328 | 5.5% | 139 | 9.0% | 247 | 16.4% | 120 | 14.3% | 243 | 16.1% | |
41–50 | 2759 | 24.4% | 1369 | 23.1% | 367 | 23.6% | 455 | 30.2% | 226 | 26.9% | 342 | 22.6% | |
51–60 | 51-60y | 30.4% | 1842 | 31.1% | 424 | 27.3% | 406 | 26.9% | 287 | 34.1% | 481 | 31.8% | |
>60 | 4052 | 35.8% | 2375 | 40.2% | 623 | 40.1% | 401 | 26.6% | 208 | 24.7% | 445 | 29.5% | |
Menopausal status | Pre/peri | 3796 | 33.5% | 1797 | 30.4% | 505 | 32.5% | 612 | 40.6% | 316 | 37.6% | 566 | 37.5% |
Post | 7075 | 62.5% | 3886 | 65.7% | 979 | 63.0% | 835 | 55.3% | 484 | 57.6% | 891 | 59.0% | |
Unknown | 457 | 4.0% | 231 | 3.9% | 69 | 4.4% | 62 | 4.1% | 41 | 4.9% | 54 | 3.6% | |
Parity (>/=24Â week-pregnancies, n) | 0 | 1746 | 15.4% | 898 | 15.2% | 266 | 17.1% | 242 | 16.0% | 135 | 16.1% | 205 | 13.6% |
1 | 2062 | 18.2% | 1052 | 17.8% | 302 | 19.4% | 285 | 18.9% | 147 | 17.5% | 276 | 18.3% | |
2 | 4238 | 37.4% | 2238 | 37.8% | 547 | 35.2% | 579 | 38.4% | 302 | 35.9% | 572 | 37.9% | |
3 | 2102 | 18.6% | 1117 | 18.9% | 264 | 17.0% | 270 | 17.9% | 165 | 19.6% | 286 | 18.9% | |
4 or more | 1180 | 10.4% | 609 | 10.3% | 174 | 11.2% | 133 | 8.8% | 92 | 10.9% | 172 | 11.4% | |
Age at menarche, years | Mean/median | 13.2/13.0 | Â | 13.2/13.0 | Â | 13.2/13.0 | Â | 13.3/13.0 | Â | 13.4/13.0 | Â | 13.2/13.0 | Â |
<12 | 1369 | 13.3% | 748 | 13.8% | 186 | 13.5% | 163 | 12.0% | 82 | 11.1% | 190 | 13.8% | |
12–13 | 2104 | 20.5% | 1066 | 19.7% | 308 | 22.4% | 289 | 21.3% | 151 | 20.4% | 290 | 21.0% | |
13–14 | 2578 | 25.1% | 1359 | 25.1% | 318 | 23.1% | 347 | 13.3% | 188 | 25.3% | 366 | 26.5% | |
>14 | 4227 | 41.1% | 2249 | 41.5% | 563 | 40.9% | 561 | 13.3% | 321 | 43.3% | 533 | 38.7% | |
Missing | 1050 | Â | 492 | Â | 178 | Â | 149 | Â | 99 | Â | 132 | Â | |
Age at FFTP, years | Mean/median | 25.1/24.0 | Â | 25.0/24.0 | Â | 25.3/25.0 | Â | 25.6/25.0 | Â | 25.6/25.0 | Â | 24.7/24.0 | Â |
<20 | 822 | 10.9% | 453 | 11.2% | 98 | 10.5% | 89 | 9.2% | 43 | 8.1% | 139 | 13.2% | |
20–25 | 2948 | 39.1% | 1613 | 39.8% | 353 | 38.0% | 340 | 35.0% | 200 | 37.8% | 442 | 42.1% | |
25–30 | 2417 | 32.1% | 1292 | 31.8% | 300 | 32.3% | 344 | 35.4% | 184 | 34.8% | 297 | 28.3% | |
>30 | 1351 | 17.9% | 699 | 17.2% | 179 | 19.2% | 198 | 20.4% | 102 | 19.3% | 173 | 16.5% | |
Missing | 2044 | Â | 1857 | Â | 623 | Â | 538 | Â | 312 | Â | 460 | Â | |