Table 1 Characteristics of the breast cancer cases and controls
Variable | Cases (n = 648) | Controls (n = 659) | P diffa |
|---|---|---|---|
Age at blood draw (years; mean ± SD) | 69.2 (5.8) | 69.3 (5.76) | P = 0.93 |
Age at diagnosis (years; mean ± SD) | 68.9 (6.25) | - | - |
BMI (kg/m2; mean ± SD) | 25.2 (4.54) | 25.5 (4.56) | P = 0.22 |
Adult weight change (lb; mean ± SD) | 27.9 (25.65) | 27.1 (25.91) | P = 0.58 |
Race (n [%]) | Â | Â | Â |
   White | 642 (99.1) | 653 (99.1) | P = 0.98 |
   Other | 6 (0.9) | 6 (0.9) |  |
BMI (kg/m2; n [%]) | Â | Â | Â |
   <25 | 364 (56.2) | 338 (51.3) | P = 0.16 |
   25–30 | 170 (26.2) | 210 (31.9) |  |
   30+ | 106 (16.4) | 103 (15.6) |  |
   Missing | 8 (1.2) | 8 (1.2) |  |
History of breast cysts (n [%]) | Â | Â | Â |
   No | 402 (62) | 460 (69.8) | P = 0.003 |
   Yes | 246 (38) | 199 (30.2) |  |
Postmenopausal hormone use (n [%]) | Â | Â | Â |
   Never | 213 (32.9) | 255 (38.7) | P < 0.0001 |
   ERT | 204 (31.5) | 260 (39.5) |  |
   CHRT | 203 (31.3) | 120 (18.2) |  |
   Unknown | 28 (4.3) | 24 (3.6) |  |
Family history of breast cancer (n [%]) | Â | Â | Â |
   No | 513 (79.2) | 564 (85.6) | P = 0.002 |
   Yes | 135 (20.8) | 95 (14.4) |  |
Education (n [%]) | Â | Â | Â |
   <High school | 7 (1.1) | 25 (3.8) | P = 0.0008 |
   High school | 166 (25.6) | 196 (29.7) |  |
   Some college | 181 (27.9) | 190 (28.8) |  |
   College + | 294 (45.4) | 248 (37.6) |  |
Age at menopause (years; n [%]) | Â | Â | Â |
   <40 | 55 (8.5) | 72 (10.9) | P = 0.002 |
   40 to 44 | 65 (10) | 85 (12.9) |  |
   45 to 49 | 139 (21.5) | 179 (27.2) |  |
   50 to 54 | 301 (46.5) | 258 (39.2) |  |
   55+ | 88 (13.6) | 65 (9.9) |  |