Table 3.
Pooled RRs of cancer risk for the highest versus lowest categories of soy paste, miso soup, natto, fermented soy foods and unfermented soy foods consumption.
| Characteristic | Studies (n) | RR (95% CI) | Heterogeneity | p-Difference |
|---|---|---|---|---|
| Soy paste | ||||
| All studies | 12 | 0.99 (0.87, 1.13) | I2 = 75.2%, p < 0.001 | |
| Study design | ||||
| Case–control study | 8 | 1.06 (0.85, 1.33) | I2 = 82.1%, p < 0.001 | p = 0.271 |
| Cohort study | 4 | 0.95 (0.89, 1.01) | I2 = 0%, p = 0.401 | |
| Sex | ||||
| Male | 7 | 0.93 (0.71, 1.22) | I2 = 78.1%, p < 0.001 | p = 0.884 |
| Female | 11 | 0.92 (0.82, 1.02) | I2 = 18.8%, p = 0.264 | |
| Cancer type | ||||
| Gastrointestinal cancer | 4 | 1.23 (0.88, 1.74) | I2 = 84.7%, p < 0.001 | |
| Stomach | 3 | 1.13 (0.74, 1.73) | I2 = 80.6%, p = 0.001 | |
| Colorectal | 1 | 1.60 (1.25, 2.05) | ||
| Gynecological cancer | 5 | 0.87 (0.72, 1.05) | I2 = 32.2%, p = 0.207 | p = 0.117 |
| Breast | 4 | 0.82 (0.70, 0.96) | I2 = 0%, p = 0.520 | |
| Endometrial | 1 | 1.31 (0.83, 2.07) | ||
| Upper aerodigestive tract cancer | 1 | 0.90 (0.79, 1.02) | p = 0.441 | |
| Liver cancer | 1 | 0.81 (0.60, 1.10) | p = 0.352 | |
| Geographic location | ||||
| Japan | 4 | 0.88 (0.75, 1.03) | I2 = 39.4%, p = 0.175 | |
| Korea | 4 | 1.23 (0.88, 1.74) | I2 = 84.7%, p < 0.001 | p = 0.093 |
| China | 2 | 0.90 (0.80, 1.02) | I2 = 0%, p = 0.900 | p = 0.997 |
| USA | 1 | 1.31 (0.83, 2.07) | p = 0.236 | |
| Europe | 1 | 0.79 (0.61, 1.02) | p = 0.593 | |
| Miso soup | ||||
| All studies | 10 | 0.99 (0.87, 1.12) | I2 = 15.3%, p = 0.302 | |
| Study design | ||||
| Case–control study | 6 | 0.98 (0.76, 1.27) | I2 = 39.2%, p = 0.144 | p = 0.780 |
| Cohort study | 4 | 0.97 (0.84, 1.11) | I2 = 0%, p = 0.514 | |
| Sex | ||||
| Male | 5 | 1.01 (0.77, 1.32) | I2 = 50.4%, p = 0.089 | p = 0.682 |
| Female | 7 | 0.97 (0.84, 1.12) | I2 = 0%, p = 0.508 | |
| Cancer type | ||||
| Gastrointestinal cancer | 4 | 1.01 (0.83, 1.22) | I2 = 34.1%, p = 0.207 | |
| Stomach | 3 | 1.12 (0.78, 1.61) | I2 = 55.5%, p = 0.106 | |
| Colorectal | 1 | 0.96 (0.78, 1.19) | ||
| Breast cancer | 2 | 1.05 (0.86, 1.28) | I2 = 0%, p = 0.681 | p = 0.648 |
| Liver cancer | 1 | 0.5 (0.15, 1.66) | p = 0.442 | |
| Lung cancer | 1 | 0.53 (0.28, 1.01) | p = 0.234 | |
| Upper aerodigestive tract cancer | 1 | 1.63 (0.51, 5.21) | p = 0.539 | |
| Non-Hodgkin lymphoma | 1 | 1.01 (0.60, 1.70) | p = 0.933 | |
| Geographic location | ||||
| Japan | 7 | 0.94 (0.80, 1.10) | I2 = 24.7%, p = 0.240 | p = 0.188 |
| USA | 3 | 1.15 (0.91, 1.47) | I2 = 0%, p = 0.791 | |
| Natto | ||||
| All studies | 7 | 0.96 (0.82, 1.11) | I2 = 33.8%, p = 0.170 | |
| Study design | ||||
| Case–control study | 4 | 0.74 (0.58, 0.95) | I2 = 0%, p = 0.592 | p = 0.045 |
| Cohort study | 3 | 1.05 (0.98, 1.13) | I2 = 0%, p = 0.952 | |
| Sex | ||||
| Male | 5 | 0.96 (0.74, 1.26) | I2 = 57.6%, p = 0.051 | p = 0.402 |
| Female | 6 | 0.99 (0.90, 1.10) | I2 = 0%, p = 0.680 | |
| Cancer type | ||||
| Breast cancer | 2 | 0.97 (0.73, 1.29) | I2 = 0%, p = 0.336 | |
| Prostate cancer | 1 | 0.25 (0.05, 1.24) | p = 0.350 | |
| Lung cancer | 1 | 0.74 (0.51, 1.07) | p = 0.453 | |
| Non-Hodgkin lymphoma | 1 | 0.76 (0.46, 1.24) | p = 0.550 | |
| Liver caner | 1 | 1.10 (0.80, 1.51) | p = 0.67 | |
| Fermented soy foods | ||||
| All studies | 7 | 1.18 (0.95, 1.47) | I2 = 77.3%, p < 0.001 | |
| Study design | ||||
| Case-control study | 3 | 1.74 (0.96, 3.15) | I2 = 81.8%, p = 0.004 | p = 0.056 |
| Cohort study | 4 | 0.99 (0.93, 1.06) | I2 = 0%, p = 0.805 | |
| Sex | ||||
| Male | 5 | 1.03 (0.91, 1.17) | I2 = 19.3%, p = 0.292 | p = 0.573 |
| Female | 5 | 0.98 (0.89, 1.09) | I2 = 0%, p = 0.460 | |
| Cancer type | ||||
| Stomach cancer | 2 | 0.96 (0.79, 1.17) | I2 = 0%, p = 0.393 | |
| Breast cancer | 1 | 0.94 (0.67, 1.32) | p = 0.935 | |
| Prostate cancer | 1 | 2.02 (1.08, 3.78) | p = 0.270 | |
| Liver cancer | 1 | 1.08 (0.78, 1.50) | p = 0.656 | |
| Upper aerodigestive tract cancer | 1 | 2.55 (1.71, 3.80) | p = 0.146 | |
| Geographic location | ||||
| Japan | 4 | 0.99 (0.93, 1.06) | I2 = 0%, p = 0.805 | |
| China | 2 | 2.38 (1.70, 3.34) | I2 = 0%, p = 0.539 | p = 0.008 |
| Korea | 1 | 1.08 (0.77, 1.51) | p = 0.698 | |
| Unfermented soy foods | ||||
| All studies | 6 | 0.95 (0.77, 1.18) | I2 = 75.8%, p = 0.001 | |
| Study design | ||||
| Case–control study | 2 | 0.86 (0.44, 1.67) | I2 = 80.7%, p = 0.023 | p = 0.624 |
| Cohort study | 4 | 1.00 (0.80, 1.25 | I2 = 76.3%, p = 0.005 | |
| Sex | ||||
| Male | 4 | 0.81 (0.60, 1.10) | I2 = 82.6%, p = 0.001 | p = 0.239 |
| Female | 6 | 1.08 (0.93, 1.25) | I2 = 24.6%, p = 0.249 | |
| Cancer type | ||||
| Stomach cancer | 2 | 0.65 (0.52, 0.80) | I2 = 0%, p = 0.789 | |
| Breast cancer | 2 | 1.17 (0.91, 1.51) | I2 = 0%, p = 0.832 | p = 0.073 |
| Liver cancer | 1 | 1.21 (0.92, 1.60) | p = 0.178 | |
| Geographic location | ||||
| Japan | 4 | 1.00 (0.80, 1.25) | I2 = 76.3%, p = 0.005 | |
| China | 1 | 1.22 (0.78, 1.91) | p = 0.613 | |
| Korea | 1 | 0.62 (0.43, 0.90) | p = 0.253 |