Table 1.
Selected risk factors and mammographic density measures by menopausal status (MTC, 2006)
| Premenopausal N=1007 | Postmenopausal N=600 | |
|---|---|---|
| Mean (SD) | ||
| Age (years) | 43.3 (4.1) | 53.4 (5.3) |
| BMI (kg/m2) | 28.4 (5.2) | 29.2 (5.1) |
| BMI at age18 (kg/m2) | 21.2 (2.9) | 21.2 (3.0) |
| Weight change since age 18 (lbs) | 17.5 (11.5) | 19.2 (12.1) |
| Parity (among parous) | 2.4 (1.0) | 2.6 (1.2) |
| Percent Density | 37.1 (14.7) | 28.0 (13.6) |
| Dense Area (cm2) | 48.6 (29.1) | 39.9 (27.2) |
| Non-dense Area (cm2) | 81.6 (36.5) | 102.2 (42.7) |
| N (Percent) | ||
| Nulliparous | 124 (12.9%) | 80 (14.1%) |
| Family history of breast cancer | 50 (5.0%) | 40 (6.7%) |
| History of BBD | 140 (13.9%) | 67 (11.2%) |
| Indigenous language/dialect | 41 (4.1%) | 24 (4.1%) |
| Age at menarche | ||
| <12 | 234 (23.5%) | 147 (25.1%) |
| 12 | 284 (28.5%) | 158 (27.0%) |
| 13 | 235 (23.6%) | 106 (18.1%) |
| 14+ | 242 (24.3%) | 175 (29.9%) |
| Age at first pregnancy (among parous) | ||
| <25 | 423 (51.3%) | 236 (49.0%) |
| 25+ | 401 (48.7%) | 246 (51.0%) |
| Breastfeeding (among parous) | ||
| Never breastfed | 95 (11.5%) | 77 (16.3%) |
| <12 months | 359 (43.6%) | 203 (42.9%) |
| 12+ months | 369 (44.8%) | 193 (40.8%) |
| Hormonal contraceptives | ||
| Never | 461 (47.5%) | 284 (49.8%) |
| Past use | 402 (41.4%) | 286 (50.2%) |
| Current use | 25 (2.6%) | -- |
| Ever use – current status unknown | 83 (8.5%) | -- |
| Alcohol | ||
| None | 265 (28.8%) | 167 (30.8%) |
| Any | 656 (71.2%) | 375 (69.2%) |
| Age at natural menopause | ||
| <45 | -- | 142 (26.4%) |
| 45–49 | -- | 234 (43.4%) |
| 50+ | -- | 163 (30.2%) |
| HT use | ||
| Never | -- | 390 (67.2%) |
| Past | 102 (17.6%) | |
| Current | 41 (7.1%) | |
| Ever use – current status unknown | -- | 47 (8.1%) |
| State | ||
| Jalisco | 574 (57.0%) | 217 (36.2%) |
| Veracruz | 433 (43.0%) | 383 (63.8%) |
BMI=body mass index; BBD=benign breast disease; HT=hormone therapy use
Number missing for each of the selected risk factors (none missing unless otherwise indicated): BMI at age 18 (N=100), weight change since age 18 (N=100), parity (N=74), indigenous language/dialect (n=21), age at menarche (N=26), age at first pregnancy among parous (N=23), breastfeeding among parous (N=33), hormonal contraceptive use (N=66), alcohol use (N=144), PMH use (N=20), age at natural menopause (N=61)