Table 1.
Characteristics of the study population
| All | ||||||||
| Native | ||||||||
| Characteristic | Caucasian | Chinese | Japanese | Hawaiian | Others | Mean | SD | P* |
| Number | 182 | 72 | 157 | 63 | 40 | 514 | 0.001 | |
| Age (years) | 54.1 | 56.8 | 53.3 | 52.7 | 51.8 | 53.9 | 10.1 | 0.064 |
| Body mass index | 25.3 | 22.8 | 23.2 | 30.3 | 25.4 | 24.9 | 5.8 | 0.001 |
| Years of education | 16.1 | 16.7 | 16.1 | 14.6 | 14.1 | 15.8 | 3.1 | 0.001 |
| Family history of breast cancer (%) | 14.3 | 9.7 | 13.4 | 14.3 | 14.3 | 13.0 | 0.848 | |
| Age at menarche (years) | 12.5 | 12.2 | 12.2 | 12.4 | 12.8 | 12.4 | 1.5 | 0.130 |
| Age at first live birth (years) | 24.9 | 26.7 | 27.0 | 21.6 | 24.4 | 25.3 | 5.3 | 0.001 |
| Percent postmenopausal | 59.9 | 63.9 | 55.4 | 55.6 | 60.0 | 58.6 | 0.757 | |
| Daily caloric intake (kcal) | 2022 | 1806 | 2020 | 2886 | 2766 | 2155 | 1413 | 0.001 |
| Percent calories from fat (%) | 30.3 | 27.5 | 29.6 | 31.0 | 31.7 | 29.9 | 6.4 | 0.003 |
| Fruits and vegetables (servings/day) | 5.5 | 5.2 | 5.1 | 6.9 | 6.4 | 5.6 | 4.2 | 0.212 |
| Meat (g/day) | 86.9 | 87.9 | 100.1 | 145.5 | 169.3 | 104.7 | 100.2 | 0.001 |
| Rice (g/day) | 89.5 | 206.5 | 240.3 | 206.8 | 258.5 | 179.5 | 163.6 | 0.001 |
| Alcohol (g/day) | 111.7 | 32.4 | 27.0 | 76.7 | 74.2 | 67.5 | 185.5 | 0.001 |
| All soy foods (SQ) (g/day) | 22.3 | 37.6 | 39.4 | 51.9 | 72.4 | 37.2 | 86.3 | 0.001 |
| All soy foods (FQ) (g/day) | 10.6 | 20.7 | 27.2 | 25.7 | 24.3 | 20.0 | 32.2 | 0.001 |
| All tofu (SQ) (g/day) | 8.6 | 18.6 | 21.0 | 26.8 | 14.2 | 16.4 | 31.9 | 0.001 |
| Tofu (FFQ) (g/day) | 9.2 | 18.9 | 24.4 | 23.8 | 22.1 | 18.0 | 30.7 | 0.001 |
| Soy milk/drinks (SQ) (g/day) | 7.4 | 6.3 | 5.6 | 4.7 | 29.1 | 8.1 | 45.9 | 0.005 |
| Green soybeans (SQ) (g/day) | 1.4 | 2.6 | 4.8 | 9.2 | 6.2 | 3.9 | 16.2 | 0.001 |
| Soybean sprouts (SQ) (g/day) | 1.3 | 1.6 | 1.9 | 6.0 | 4.9 | 2.4 | 6.9 | 0.001 |
| Other soy foods (SQ) (g/day) | 3.7 | 8.5 | 6.1 | 5.2 | 17.9 | 6.4 | 25.7 | < 0.001 |
| Breast area (103 pixels) | 1209 | 807 | 789 | 1353 | 1146 | 1037 | 588 | < 0.001 |
| Dense area (103 pixels) | 296 | 246 | 254 | 307 | 304 | 278 | 171 | 0.460 |
| Mammographic percent density (%) | 29.0 | 36.0 | 34.9 | 26.4 | 31.2 | 31.6 | 16.9 | < 0.001 |
| Nondense area (103 pixels) pixels) | 914 | 561 | 535 | 1046 | 842 | 759 | 557 | < 0.001 |
FFQ, Food frequency questionnaire; SQ, soy questionnaire. *Probabilities for ethnic differences were obtained through either one-way analysis of variance or chi-square tests.