Table 2. Stratified analysis of colorectal cancer in relation to soy isoflavone consumption according to study characteristics.
| Group | No. of studies | RR (95% CI) | P heterogeneity | I2 (%) |
|---|---|---|---|---|
| Soy types and colorectal cancer | ||||
| Soy foods/products | 14 | 0.79 (0.69–0.89) | 0.006 | 46.2% |
| Isoflavones | 8 | 0.76 (0.69–0.83) | 0.559 | 0 |
| Gender | ||||
| Male | 6 | 0.86 (0.73–0.99) | 0.085 | 38.4% |
| Female | 8 | 0.74 (0.66–0.83) | 0.493 | 0 |
| anatomical subsite | ||||
| Colorectal | 12 | 0.77 (0.70–0.84) | 0.092 | 28.6% |
| Colon | 4 | 0.85 (0.64–1.05) | 0.082 | 44.6% |
| Rectum | 3 | 0.87 (0.52–1.22) | 0.05 | 61.7% |
| Study types | ||||
| Cohort | 4 | 0.83 (0.71–0.95) | 0.118 | 35.1% |
| Case-control | 13 | 0.76 (0.68–0.84) | 0.045 | 34.4% |
| Geographic area | ||||
| Asia | 12 | 0.79 (0.72–0.87) | 0.01 | 41.1% |
| Non-Asia | 5 | 0.74 (0.64–0.83) | 0.722 | 0 |
No, number; RR, relative risk; CI, confidence interval.