Characteristics | Cases (n = 1,631) | Controls (n = 1,435) |
---|---|---|
Age (years)a | Â | Â |
   35 to 39 | 306 (18.8) | 230 (16.0) |
   40 to 44 | 243 (14.9) | 246 (17.1) |
   45 to 49 | 260 (15.9) | 236 (16.5) |
   50 to 54 | 295 (18.1) | 229 (16.0) |
   55 to 59 | 269 (16.5) | 265 (18.5) |
   60 to 64 | 258 (15.8) | 229 (16.0) |
Racea | Â | Â |
   Caucasian | 1143 (70.1) | 987 (68.8) |
   African-American | 488 (29.9) | 448 (31.2) |
Menopausal status | Â | Â |
   Premenopausal | 964 (59.1) | 784 (54.6) |
   Postmenopausal | 667 (40.9) | 651 (45.4) |
History of breast cancera | Â | Â |
   First-degree family history | 610 (37.4) | 338 (23.6) |
   No first-degree family history | 969 (59.4) | 1057 (73.7) |
   Adopted or unknown first degree | 52 (3.2) | 40 (2.8) |
Body mass index (kg/m2) | Â | Â |
   Underweight (<18.5) | 31 (1.9) | 40 (2.8) |
   Normal (18.5 to 24.9) | 898 (55.3) | 726 (50.7) |
   Overweight (25.0 to 29.9) | 436 (26.8) | 384 (26.8) |
   Obese (≥30) | 260 (16.0) | 283 (19.8) |
Oral contraceptive use | Â | Â |
   Never | 358 (22.0) | 274 (19.1) |
   Former | 1190 (73.0) | 1098 (76.5) |
   Current | 82 (5.0) | 63 (4.4) |
Unopposed estrogen hormone therapy useb | Â | Â |
   Never | 1004 (61.6) | 816 (56.9) |
   Former | 130 (8.0) | 129 (9.0) |
   Current (within 6 months) | 206 (12.6) | 245 (17.1) |
Estrogen plus progestin hormone therapy useb | Â | Â |
   Never | 1004 (61.6) | 816 (56.9) |
   Former | 75 (4.6) | 91 (6.3) |
   Current (within 6 months) | 241 (14.8) | 187 (13) |
Smoking status | Â | Â |
   Ever | 893 (54.8) | 769 (53.6) |
   Never | 738 (45.2) | 666 (46.4) |