Table 2.
Summary of pooled risk ratios of bladder cancer for fish consumer by study design, geographical region, and exposure assessment
| Subgroup | Number of studies | Pooled RR (95% CI) |
Q-test for heterogeneity | |
|---|---|---|---|---|
| P value | I2 score | |||
| Study design | ||||
| Cohort studies | 5 | 0.84 (0.42, 1.26) | 0.023 | 64.8% |
| Case-control studies | 9 | 0.87 (0.54, 1.21) | < 0.001 | 89.7% |
| Hospital-based case-control studies | 6 | 0.88 (0.40, 1.36) | < 0.001 | 92.5% |
| Population-based case-control studies | 3 | 0.83 (0.63, 1.03) | 0.586 | 0 |
| Geographical region | ||||
| Europe | 7 | 0.95 (0.49, 1.42) | < 0.001 | 91.9% |
| US/Canada | 3 | 0.80 (0.58, 1.02) | 0.891 | 0 |
| Japan | 3 | 0.76 (0.25, 1.27) | 0.019 | 74.7% |
| Exposure assessment | ||||
| Interview | 6 | 0.88 (0.40, 1.36) | < 0.001 | 92.5% |
| Mailed questionnaire | 7 | 0.84 (0.58, 1.09) | 0.025 | 58.5% |
| Case sample size | ||||
| Large | 7 | 0.99 (0.82, 1.17) | 0.215 | 28.0% |
| Small | 7 | 0.68 (0.34, 1.02) | < 0.001 | 81.4% |