Table 1.
Demographic characteristics of the study population
| Characteristic | Controls (n = 877)
|
Ductal Cases (n = 891)
|
Lobular Cases (n = 1,036)
|
|||
|---|---|---|---|---|---|---|
| No. | % | No. | % | No. | % | |
| Age at reference date | ||||||
| 55 - 59 | 252 | 28.7% | 259 | 29.1% | 306 | 29.5% |
| 60 - 64 | 230 | 26.2% | 245 | 27.5% | 294 | 28.4% |
| 65 - 69 | 222 | 25.3% | 211 | 23.7% | 241 | 23.3% |
| 70 - 74 | 173 | 19.7% | 176 | 19.8% | 195 | 18.8% |
| Race/ethnicity | ||||||
| Non-Hispanic White | 778 | 88.9% | 804 | 90.4% | 960 | 92.8% |
| African American | 27 | 3.1% | 22 | 2.5% | 14 | 1.4% |
| Asian/Pacific Islander | 17 | 1.9% | 35 | 3.9% | 21 | 2.0% |
| Native American | 24 | 2.7% | 16 | 1.8% | 20 | 1.9% |
| Hispanic White | 29 | 3.3% | 12 | 1.3% | 20 | 1.9% |
| Missing | 2 | 2 | 1 | |||
| Education | ||||||
| Less than high school | 39 | 4.5% | 46 | 5.2% | 62 | 6.0% |
| High school graduate | 207 | 23.6% | 207 | 23.3% | 365 | 35.2% |
| Some college | 343 | 39.2% | 331 | 37.2% | 221 | 21.3% |
| College degree or higher | 287 | 32.8% | 306 | 34.4% | 388 | 37.5% |
| Missing | 1 | 1 | 0 | |||
| Annual household income | ||||||
| < $20,000 | 82 | 10.7% | 102 | 12.9% | 100 | 11.0% |
| $20,000 - $34,999 | 138 | 18.0% | 129 | 16.3% | 173 | 19.1% |
| $35,000 - $69,999 | 285 | 37.1% | 273 | 34.6% | 294 | 32.5% |
| $70,000 - $89,999 | 88 | 11.5% | 102 | 12.9% | 132 | 14.6% |
| ≥ $90,000 | 175 | 22.8% | 184 | 23.3% | 207 | 22.8% |
| Missing | 109 | 101 | 130 | |||
| Alcohol use | ||||||
| None | 441 | 50.6% | 419 | 47.4% | 480 | 46.6% |
| < 1 drink per day | 299 | 34.3% | 312 | 35.3% | 345 | 33.5% |
| ≥ 1 drink per day | 132 | 15.1% | 153 | 17.3% | 205 | 19.9% |
| Missing | 5 | 7 | 6 | |||
| Smoking status | ||||||
| Never | 440 | 50.2% | 445 | 50.0% | 495 | 47.8% |
| Former | 348 | 39.7% | 342 | 38.4% | 416 | 40.2% |
| Current | 88 | 10.0% | 103 | 11.6% | 125 | 12.1% |
| Missing | 1 | 1 | 0 | |||
| Body mass index, kg/m2 | ||||||
| < 25 | 264 | 30.4% | 285 | 32.0% | 367 | 35.5% |
| 25 - 29.9 | 300 | 34.5% | 283 | 31.8% | 342 | 33.1% |
| ≥ 30 | 305 | 35.1% | 322 | 36.2% | 324 | 31.4% |
| Missing | 8 | 1 | 3 | |||
| History of high cholesterol | ||||||
| No | 602 | 68.8% | 604 | 67.9% | 713 | 69.0% |
| Yes | 273 | 31.2% | 286 | 32.1% | 320 | 31.0% |
| Missing | 2 | 1 | 3 | |||
| History of heart disease | ||||||
| No | 385 | 44.0% | 406 | 45.7% | 471 | 45.6% |
| Yes | 490 | 56.0% | 482 | 54.3% | 563 | 54.4% |
| Missing | 2 | 3 | 2 | |||
| First degree family history of breast cancer | ||||||
| No | 697 | 82.2% | 654 | 76.7% | 771 | 76.8% |
| Yes | 151 | 17.8% | 199 | 23.3% | 233 | 23.2% |
| Missing | 29 | 38 | 32 | |||
| Mammography screening history | ||||||
| Less than annual | 394 | 45.1% | 409 | 46.0% | 490 | 47.6% |
| Annual only | 469 | 53.7% | 462 | 52.0% | 521 | 50.6% |
| More than annual | 11 | 1.3% | 18 | 2.0% | 19 | 1.9% |
| Missing | 3 | 2 | 6 | |||
| Hormone therapy use | ||||||
| Never | 249 | 28.4% | 322 | 36.1% | 261 | 25.2% |
| Former | 310 | 35.3% | 242 | 27.2% | 256 | 24.7% |
| Current estrogen only | 202 | 23.0% | 162 | 18.2% | 219 | 21.1% |
| Current estrogen + progestin | 116 | 13.2% | 165 | 18.5% | 300 | 29.0% |