Characteristic | Level | MCBCSa (n = 484) | SASBACb (n = 726) | ||
---|---|---|---|---|---|
 |  | N | % or mean | N | % or mean |
Age, years | 40 to 49 | 26 | 5.4 | 1 | 0.1 |
 | 50 to 59 | 157 | 32.4 | 237 | 32.6 |
 | 60 to 69 | 176 | 36.4 | 363 | 50.0 |
 | 70+ | 125 | 25.8 | 125 | 17.2 |
Body mass index, kg/m2 | Mean (SD) | 464 | 26.9 (5.3) | 718 | 25.7 (4.1) |
Postmenopausal hormone use | Current | 153 | 31.6 | 95 | 13.1 |
 | Former | 163 | 33.7 | 186 | 25.6 |
 | Never | 136 | 28.1 | 362 | 49.9 |
 | Unknown | 32 | 6.6 | 83 | 11.4 |
Percent Mammographic Density, (%) | Mean (SD) | 484 | 18.6 (13.9) | 726 | 14.4 (13.9) |
Categories | 0 | 30 | 6.2 | 45 | 6.2 |
 | 1 to 9 | 116 | 24.0 | 324 | 44.6 |
 | 10 to 24 | 201 | 41.5 | 225 | 31.0 |
 | 25 to 49 | 125 | 25.8 | 111 | 15.3 |
 | 50 to 74 | 11 | 2.3 | 21 | 2.9 |
 | 75+ | 1 | 0.2 | 0 | 0 |