|  | Cases (n = 798) | Controls (n = 843) | ||
---|---|---|---|---|---|
Characteristic | Level | n | %a | n | % |
Age (years) | 20 to 39 | 56 | 7 | 48 | 6 |
 | 40 to 49 | 192 | 24 | 166 | 20 |
 | 50 to 59 | 224 | 28 | 274 | 32 |
 | 60 to 69 | 195 | 24 | 207 | 25 |
 | 70+ | 131 | 16 | 148 | 18 |
State of residence | Minnesota | 502 | 63 | 552 | 66 |
 | Wisconsin | 69 | 9 | 78 | 9 |
 | Iowa | 128 | 16 | 147 | 17 |
 | North Dakota/South Dakota | 52 | 6 | 41 | 5 |
 | Illinois | 47 | 6 | 25 | 3 |
Body mass index (kg/m2) | Mean (standard deviation) | 28 | 8 | 27 | 8 |
Family historyb | Yes | 366 | 47 | 345 | 43 |
Postmenopausal status | Yes | 480 | 64 | 579 | 72 |
Age at menarche (years) | <12 | 132 | 18 | 122 | 16 |
 | 12 | 224 | 31 | 184 | 24 |
 | 13 | 218 | 30 | 238 | 32 |
 | ≥ 14 | 154 | 21 | 209 | 28 |
Oral contraceptive use | 0 months | 266 | 35 | 243 | 31 |
 | 1 to 48 months | 185 | 24 | 189 | 24 |
 | 48+ months | 310 | 41 | 345 | 44 |
Postmenopausal hormone use | 0 months | 430 | 58 | 366 | 49 |
 | 1 to 60 months | 131 | 18 | 160 | 22 |
 | 60+ months | 184 | 25 | 216 | 29 |
Age at first birth (years) | Nulliparous | 97 | 13 | 128 | 16 |
 | ≤ 20 years | 173 | 22 | 158 | 20 |
 | >20 years | 501 | 65 | 514 | 64 |
Smoking (pack years) | None | 467 | 63 | 500 | 66 |
 | ≤ 4 years | 46 | 6 | 67 | 9 |
 | >4 years | 231 | 31 | 192 | 25 |
Alcohol consumption | Never | 92 | 12 | 94 | 12 |
 | Monthly | 332 | 43 | 327 | 41 |
 | Weekly | 259 | 34 | 299 | 37 |
 | Daily | 83 | 11 | 79 | 10 |