TABLE 3.
Multivariable HRs for postdiagnosis baseline isoflavone intake in association with all-cause mortality, breast cancer–specific mortality, and breast cancer recurrence: After Breast Cancer Pooling Project (n = 9514)1
| All-cause mortality | Breast cancer–specific mortality | Breast cancer recurrence | |||||
| Isoflavones | Cohort | Events | HR (95% CI) | Events | HR (95% CI) | Events | HR (95% CI) |
| n | n | n | n | ||||
| Study-specific deciles | |||||||
| 1 | 949 | 140 | 1.00 (reference) | 108 | 1.00 (reference) | 165 | 1.00 (reference) |
| 2 | 952 | 113 | 0.78 (0.60, 1.00) | 82 | 0.74 (0.56, 0.99) | 123 | 0.72 (0.57, 0.91) |
| 3 | 953 | 126 | 0.91 (0.71, 1.17) | 86 | 0.80 (0.60, 1.07) | 140 | 0.86 (0.68, 1.08) |
| 4 | 950 | 113 | 0.78 (0.60, 1.00) | 79 | 0.69 (0.52, 0.93) | 133 | 0.75 (0.60, 0.95) |
| 5 | 951 | 118 | 0.83 (0.65, 1.07) | 90 | 0.81 (0.61, 1.07) | 120 | 0.69 (0.54, 0.88) |
| 6 | 953 | 119 | 0.89 (0.69, 1.14) | 92 | 0.86 (0.65, 1.15) | 134 | 0.78 (0.62, 0.99) |
| 7 | 952 | 117 | 0.83 (0.65, 1.07) | 88 | 0.77 (0.58, 1.03) | 138 | 0.77 (0.61, 0.99) |
| 8 | 952 | 118 | 0.94 (0.73, 1.21) | 92 | 0.86 (0.65, 1.15) | 139 | 0.83 (0.66, 1.05) |
| 9 | 953 | 105 | 0.85 (0.65, 1.10) | 89 | 0.87 (0.65, 1.16) | 142 | 0.85 (0.67, 1.07) |
| 10 | 949 | 102 | 0.82 (0.63, 1.08) | 75 | 0.71 (0.52, 0.97) | 114 | 0.64 (0.50, 0.82) |
| P-trend | 0.6354 | 0.4974 | 0.0759 | ||||
| Common cutoffs (mg/d)2 | |||||||
| <4.0 | 4,131 | 635 | 1.00 (reference) | 431 | 1.00 (reference) | 730 | 1.00 (reference) |
| 4.0–9.99 | 613 | 73 | 1.04 (0.80, 1.36) | 60 | 1.09 (0.81, 1.48) | 92 | 0.99 (0.78, 1.25) |
| ≥10.0 | 4,770 | 463 | 0.87 (0.70, 1.10) | 390 | 0.83 (0.64, 1.07) | 526 | 0.75 (0.61, 0.92) |
HRs were derived from delayed-entry Cox proportional hazards regression models and adjusted for age at diagnosis, estrogen receptor/progesterone receptor status, TNM stage, chemotherapy, radiotherapy, hormonal therapy, smoking, BMI, exercise, cruciferous vegetable intake, parity, menopausal status, study, race-ethnicity, and education.
Based on the distribution of daily isoflavone intake in the US cohorts (4.0 mg is approximately the 85th percentile, and 10.0 mg is the 90th percentile); 10.0 mg is the approximate cutoff for the lowest decile of isoflavone intake in the Chinese cohort.