Table 1.
Demographic characteristics and laboratory results of participants
| Total (N = 469) | Breast cancer (N = 233) | Control (N = 236) | |||||
|---|---|---|---|---|---|---|---|
| Variable | Range | Mean ± SD | Range | Mean ± SD | Range | Mean ± SD | P value |
| Age (years) | 28–83 | 55.4 ± 9.7 | 28–83 | 55.9 ± 10.4 | 29–80 | 54.9 ± 9 | 0.252 |
| BMI (kg/m2) | 15.98–38.34 | 23.65 ± 3.73 | 16.21–38.34 | 24.32 ± 3.92 | 15.98–36.51 | 22.98 ± 3.42 | <0.001 |
| Education | 0.153 | ||||||
| Junior high school or lower | 198 (42.2) | 106 (45.5) | 92 (39.0) | ||||
| Senior high school or higher | 271 (57.8) | 127 (54.5) | 144 (61.0) | ||||
| Menarche | 0.117 | ||||||
| 11–14 years old | 305 (65.0) | 160 (68.7) | 145 (61.4) | ||||
| 15 years old | 89 (19.0) | 35 (15.0) | 54 (22.9) | ||||
| ≥ 16 years old | 75 (16.0) | 38 (16.3) | 37 (15.7) | ||||
| Primiparity | 0.011 | ||||||
| ≤ 30 years | 348 (74.2) | 160 (68.7) | 188 (79.7) | ||||
| > 30 years | 59 (12.6) | 39 (16.7) | 20 (8.5) | ||||
| never | 62 (13.2) | 34 (14.6) | 28 (11.9) | ||||
| Menopause | <0.001 | ||||||
| Not yet | 135 (28.9) | 79 (34.1) | 56 (23.7) | ||||
| < 45 years old | 71 (15.2) | 32 (13.8) | 39 (16.5) | ||||
| 45–55 years old | 247 (52.8) | 111 (47.8) | 136 (57.6) | ||||
| ≥ 55 years old | 15 (3.2) | 10 (4.3) | 5 (2.1) | ||||
| Family history (BC) | 0.390 | ||||||
| Present | 41 (8.7) | 23 (9.9) | 18 (7.6) | ||||
| Absent | 428 (91.3) | 210 (90.1) | 218 (92.4) | ||||
| Oral contraceptive | 0.604 | ||||||
| Current user | 18 (3.8) | 7 (3.0) | 11 (4.7) | ||||
| Prior user | 97 (20.7) | 47 (20.2) | 50 (21.2) | ||||
| Never | 354 (75.5) | 179 (76.8) | 175 (74.1) | ||||
| Hormone replacement therapy | 0.503 | ||||||
| Never | 386 (82.3) | 189 (81.1) | 197 (83.5) | ||||
| Ever | 83 (17.7) | 44 (18.8) | 39 (16.5) | ||||
| Regular exercise | 0.358 | ||||||
| Yes | 191 (40.7) | 90 (38.6) | 101 (42.8) | ||||
| No | 278 (59.3) | 143 (61.4) | 135 (57.2) | ||||
| Exercise frequency | 0.009 | ||||||
| 0 | 275 (58.6) | 142 (60.9) | 133 (56.4) | ||||
| 0.5–4/week | 115 (24.5) | 44 (18.9) | 71 (30.1) | ||||
| > 4.1/week | 79 (16.8) | 47 (20.2) | 32 (13.6) | ||||
| Exercise time | 0.884 | ||||||
| ≤ 30 min | 363 (77.4) | 181 (77.7) | 182 (77.1) | ||||
| > 30 min | 106 (22.6) | 52 (23.3) | 54 (22.0) | ||||
| Vegetarian (≥12 months) | 0.002 | ||||||
| yes | 195 (41.6) | 80 (34.3) | 115 (48.7) | ||||
| no | 274 (58.4) | 153 (65.7) | 121 (51.3) | ||||
| Daily isoflavones intakea | 0–285 | 21.8 ± 21.3 | 0–88.5 | 17.2 ± 16 | 0–285 | 26.3 ± 24.7 | <0.001 |
| Serum level | |||||||
| Albumin level (g/dL) | 2.4–5.0 | 3.99 ± 0.34 | 2.4–4.8 | 3.85 ± 0.36 | 3.1–5.0 | 4.12 ± 0.27 | 0.004 |
| Triglyceride (mg/dL) | 21–681 | 106.1 ± 62.8 | 21–438 | 107.5 ± 62.6 | 25–681 | 104.7 ± 63.1 | 0.628 |
| Estradiol (pg/ml) | 2.5–787 | 55.8 ± 92.6 | 2.5–693 | 50.3 ± 74.6 | 5.2–786.4 | 61.2 ± 107.4 | 0.205 |
BMI body mass index (=BW/BH2, BW body weight; BH body height); SD standard deviation; a mg of isoflavones (aglucon equivalents) / 100 g of wet weight