TABLE 1.
Cohort overview, baseline participant characteristics, and soy isoflavone intake after diagnosis by study: After Breast Cancer Pooling Project (n = 9514)1
| SBCSS (n = 4856) | WHEL (n = 2729) | LACE (n = 1929) | |
| Study design | Prospective cohort | Prospective follow-up of participants of an RCT | Prospective cohort |
| Location | Shanghai, China | 7 sites in the Western United States | California, Utah, and WHEL sites |
| Median duration of follow-up (y) | 4.2 | 9.5 | 8.6 |
| Time of diagnosis | 2002–2006 | 1991–2000 | 1997–2000 |
| Time of recruitment | 2002–2006 | 1995–2000 | 2000–2002 |
| Age (y) | 53.5 ± 10.02 | 51.3 ± 8.9 | 58.6 ± 10.8 |
| Deaths (n) | 466 | 392 | 313 |
| Deaths from breast cancer (n) | 405 | 307 | 169 |
| Recurrences (n) | 533 | 504 | 311 |
| Race-ethnicity [n (%)] | |||
| Non-Hispanic white | NA | 2328 (85.3) | 1574 (81.6) |
| Non-Hispanic black | NA | 105 (3.9) | 86 (4.5) |
| Asian | 4856 (100) | 83 (3.0) | 117 (6.1) |
| Hispanic | NA | 149 (5.5) | 114 (5.9) |
| Other | NA | 64 (2.4) | 38 (2.0) |
| Education [n (%)] | |||
| <High school | 2258 (46.5) | 21 (0.77) | 93 (4.8) |
| High school | 1830 (37.7) | 390 (14.3) | 426 (22.1) |
| Some college/technical school | 432 (8.9) | 829 (30.4) | 717 (37.2) |
| ≥College graduate | 336 (6.9) | 1489 (54.6) | 693 (35.9) |
| Stage [n (%)] | |||
| I | 1679 (34.6) | 1060 (38.8) | 915 (47.4) |
| II | 2208 (45.5) | 1252 (45.9) | 804 (41.7) |
| III | 739 (15.2) | 417 (15.3) | 210 (10.9) |
| Missing | 230 (4.7) | 0 | 0 |
| ER/PR status [n (%)] | |||
| ER+/PR+ | 2431 (50.1) | 1692 (62.0) | 1302 (67.5) |
| ER+/PR− | 631 (13.0) | 324 (11.9) | 281 (14.6) |
| ER−/PR+ | 359 (7.4) | 111 (4.1) | 36 (1.9) |
| ER−/PR− | 1341 (27.6) | 545 (20.0) | 300 (15.6) |
| Missing | 94 (1.9) | 57 (2.1) | 10 (0.52) |
| Menopausal status [n (%)]3 | |||
| Premenopausal | 2374 (48.9) | 1387 (50.8) | 410 (21.3) |
| Postmenopausal | 2482 (51.1) | 1263 (46.3) | 1250 (64.8) |
| Missing/unclear | 0 | 79 (2.9) | 269 (14.0) |
| Chemotherapy [n (%)] | |||
| No | 380 (7.8) | 807 (29.6) | 840 (43.6) |
| Yes | 4476 (92.2) | 1922 (70.4) | 1089 (56.5) |
| Radiotherapy [n (%)] | |||
| No | 3269 (67.3) | 1036 (38.0) | 720 (37.3) |
| Yes | 1587 (32.7) | 1693 (62.0) | 1209 (62.7) |
| Hormonal therapy [n (%)] | |||
| No | 2298 (47.3) | 850 (31.2) | 388 (20.1) |
| Yes | 2542 (52.4) | 1879 (68.9) | 1541 (79.9) |
| Missing | 16 (0.3) | 0 | 0 |
| Tamoxifen use among women with ER+ breast cancer [n (%)] | |||
| No | 991 (32.1) | 377 (18.6) | 137 (8.7) |
| Yes | 2077 (67.6) | 1655 (81.5) | 1446 (91.4) |
| Missing | 6 (0.2) | 0 | 0 |
| BMI [n (%)] | |||
| <18.5 kg/m2 | 141 (2.9) | 28 (1.0) | 19 (1.0) |
| 18.5–24.99 kg/m2 | 3004 (61.9) | 1160 (42.5) | 713 (37.0) |
| 25.0–29.99 kg/m2 | 1436 (29.6) | 838 (30.7) | 639 (33.1) |
| ≥30 kg/m2 | 275 (5.7) | 703 (25.8) | 513 (26.6) |
| Missing | 0 | 0 | 45 (2.3) |
| Physical activity [n (%)] | |||
| None | 1720 (35.4) | 379 (13.9) | 282 (14.6) |
| T1 (MET-h/wk) | 841 (17.3) | 463 (17.0) | 377 (19.5) |
| T2 (MET-h/wk) | 1589 (32.7) | 938 (34.4) | 609 (31.6) |
| T3 (MET-h/wk) | 706 (14.5) | 893 (32.7) | 655 (34.0) |
| Missing | 0 | 56 (2.1) | 6 (0.3) |
| Smoking status [n (%)] | |||
| Never | 4730 (97.4) | 1458 (53.4) | 1032 (53.5) |
| Past | 94 (1.9) | 1128 (41.3) | 762 (39.5) |
| Current | 32 (0.7) | 126 (4.6) | 135 (7.0) |
| Missing | 0 | 17 (0.6) | 0 |
| Cruciferous vegetable intake, g/d [n (%)] | |||
| Q1 | 1214 (25.0) | 699 (25.6) | 476 (24.7) |
| Q2 | 1213 (25.0) | 672 (24.6) | 463 (24.0) |
| Q3 | 1213 (25.0) | 675 (24.7) | 467 (24.2) |
| Q4 | 1216 (25.1) | 683 (25.0) | 466 (24.1) |
| Missing | 0 | 0 | 57 (3.0) |
| Parity [n (%)] | |||
| Nulliparous | 197 (4.1) | 615 (22.5) | 318 (16.5) |
| 1 birth | 953 (19.6) | 410 (15.0) | 229 (11.9) |
| 2 births | 1610 (33.2) | 947 (34.7) | 612 (31.7) |
| 3 births | 1122 (23.1) | 486 (17.8) | 391 (20.3) |
| ≥4 births | 974 (20.1) | 256 (9.4) | 379 (19.7) |
| Missing | 0 | 15 (0.6) | 0 |
| Isoflavones (mg/d) | |||
| Baseline | 45.9 ± 38.3 | 2.6 ± 7.9 | 4.1 ± 11.9 |
| Mean time since diagnosis (mo) | 6.5 (3–11) | 23.4 (1–48) | 22.5 (11–38) |
1
ER, estrogen receptor; ER–, estrogen receptor–negative; ER+, estrogen receptor–positive; LACE, Life After Cancer Epidemiology Study; MET-h, metabolic equivalent task hours; NA, not applicable; PR, progesterone receptor; PR–, progesterone receptor–negative; PR+, progesterone receptor–positive; Q, quartile; RCT, randomized controlled clinical trial; SBCSS, Shanghai Breast Cancer Survival Study; T, tertile; WHEL, Women's Healthy Eating and Living Study.
2
Mean ± SD (all such values).
3
Menopausal status at diagnosis for WHEL and LACE; within 6 mo of diagnosis for SBCSS.