Characteristics | Cases N = 1,552 | Controls N = 1,363 | ||
---|---|---|---|---|
No. | % | No. | % | |
Birth cohort | ||||
≤1945 | 488 | 31.4 | 294 | 21.6 |
1946–59 | 797 | 51.4 | 706 | 51.8 |
≥1960 | 267 | 17.2 | 363 | 26.6 |
Age at censoring, years | ||||
Mean (sd) | 50.2 (9.3) | 55.8 (9.9) | ||
≤45 | 513 | 33.1 | 201 | 14.8 |
46–50 | 336 | 21.7 | 197 | 14.5 |
51–60 | 473 | 30.5 | 485 | 35.6 |
>60 | 230 | 14.8 | 480 | 35.2 |
Education level | ||||
Intermediate/high | 780 | 50.3 | 916 | 67.2 |
Basic | 714 | 46.0 | 434 | 31.8 |
Not graduated | 58 | 3.7 | 12 | 0.9 |
Missing | 0 | 0.0 | 1 | 0.1 |
Body mass index | ||||
18.5–24.9 | 1,019 | 65.6 | 869 | 63.8 |
<18.5 | 69 | 4.5 | 32 | 2.3 |
≥25 and <30 | 341 | 22.0 | 345 | 25.3 |
≥30 | 120 | 7.7 | 117 | 8.6 |
Missing | 3 | 0.2 | 0 | 0.0 |
Smoking | ||||
No | 832 | 53.6 | 680 | 49.9 |
Current | 159 | 10.2 | 158 | 11.6 |
Past | 550 | 35.4 | 514 | 37.7 |
Missing | 11 | 0.7 | 11 | 0.8 |
Number of full term pregnancies | ||||
≥2 | 445 | 28.7 | 411 | 30.2 |
1–2 | 921 | 59.3 | 763 | 56.0 |
0 | 185 | 11.9 | 187 | 13.7 |
Missing | 1 | 0.1 | 2 | 0.1 |
Age at first full-term pregnancy, years | ||||
<20 | 179 | 11.5 | 102 | 7.5 |
20–24 | 628 | 40.5 | 531 | 39.0 |
25–29 | 393 | 25.4 | 392 | 28.8 |
≥30 | 165 | 10.6 | 149 | 10.9 |
No full-term pregnancy | 185 | 11.9 | 187 | 13.7 |
Missing | 2 | 0.1 | 2 | 0.1 |
Family history of breast cancera | ||||
None | 427 | 27.5 | 959 | 70.4 |
1st degree | 818 | 52.7 | 187 | 13.7 |
Only 2nd degree | 307 | 19.8 | 216 | 15.9 |
Missing | 0 | 0.0 | 1 | 0.1 |
Tumor estrogen receptors (ER) | ||||
ER+ | 818 | 52.7 | ||
ER- | 168 | 10.8 | ||
Missing | 566 | 36.5 | ||
Gene groupb | ||||
Group “Low” | ||||
0 | 723 | 46.6 | 721 | 52.9 |
> 1 | 274 | 17.7 | 441 | 32.4 |
Group “No Effect” | ||||
0 | 575 | 37.1 | 659 | 48.4 |
>1 | 422 | 27.2 | 503 | 36.9 |
Group “High” | ||||
0 | 422 | 27.2 | 667 | 48.9 |
>1 | 575 | 37.1 | 495 | 36.3 |
Missing | 555 | 35.8 | 201 | 14.8 |