Table 1.
Characteristics of women recruited for the TMA study and the original study*
| Variable | Original study | TMA study |
|---|---|---|
| Sample size (N) | 607 | 159 |
| Ethnicity (%) | ||
| Caucasian | 185 (30.5) | 49 (30.8) |
| Hawaiian | 80 (13.2) | 21 (13.2) |
| Japanese | 287 (47.3) | 70 (44.0) |
| Other | 55 (9.1) | 19 (12.0) |
| Age at mammogram | 62.1 ± 8.5 | 59.8 ± 8.7 |
| Body mass index (m/kg2) | 25.1 ± 5.1 | 24.4 ± 4.3 |
| Family history of breast cancer (%) | 104 (17.1) | 17 (10.7) |
| Age at menarche (%) | ||
| < 13 years | 324 (54.4) | 86 (54.1) |
| 13–14 years | 217 (36.4) | 58 (36.5) |
| >14 years | 55 (9.2) | 15 (9.4) |
| Number of children (%) | ||
| 0–1 | 172 (28.3) | 43 (27.0) |
| 2 to 3 | 312 (51.4) | 86 (54.1) |
| >3 | 123 (20.3) | 30 (18.9) |
| Age at first live birth (%) | ||
| <21 years | 80 (13.6) | 21 (13.2) |
| 21–30 years | 359 (61.0) | 102 (64.2) |
| >30 years | 56 (9.5) | 11 (6.9) |
| N/A | 94 (16.0) | 25 (15.7) |
| HT use at mammogram (%) | ||
| No use | 264 (43.5) | 64 (40.3) |
| Estrogen only | 174 (28.7) | 46 (28.9) |
| Estrogen plus progestogen | 169 (27.8) | 49 (30.8) |
| Breast measures | ||
| Total breast area | 117.9 ± 58.1 | 110 ± 52.9 |
| Breast density in percent | 35.3 ± 23.3 | 38.4 ± 24.8 |
| Absolute density | 35.9 ± 27.0 | 39.5 ± 23.4 |
| Menopausal Status (%) | ||
| Premenopausal | 152 (25.0) | 60 (37.7) |
| Postmenopausal | 455 (75.0) | 99 (62.3) |
* Means ± standard deviation unless stated otherwise