Table 3. Subgroup analyses of red and processed meat intake and renal cell carcinoma risk, high vs. low.
| Sub-groups | Red meat | Processed meat | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Studies, n |
SRR (95% CI) | P for heterogeneity | I2 (%) | P for difference | Studies, n |
SRR (95% CI) | P for heterogeneity | I2 (%) | P for difference | |
| All | 19 | 1.36 (1.16–1.58) | < 0.001 | 71.3 | 19 | 1.13 (1.03–1.24) | 0.014 | 45.6 | ||
| Design | 0.751 | 0.956 | ||||||||
| Cohort | 5 | 1.07 (0.96–1.19) | 0.398 | 1.5 | 4 | 1.11 (0.99–1.25) | 0.797 | 0 | ||
| Case-control | 14 | 1.46 (1.18–1.81) | < 0.001 | 75.0 | 14 | 1.13 (1.00–1.27) | 0.004 | 55.4 | ||
| Sources of control | 0.470 | 0.152 | ||||||||
| Population-based | 8 | 1.29 (1.06–1.58) | 0.021 | 57.4 | 9 | 1.18 (1.04–1.34) | 0.024 | 54.5 | ||
| Hospital-based | 6 | 1.75 (1.10–2.78) | < 0.001 | 84.7 | 6 | 1.03 (0.79–1.34) | 0.059 | 50.6 | ||
| Geographic locations | 0.038 | 0.178 | ||||||||
| Europe | 6 | 1.04 (0.86–1.26) | 0.069 | 51.2 | 5 | 0.98 (0.78–1.23) | 0.065 | 54.7 | ||
| USA | 10 | 1.44 (1.17–1.76) | 0.001 | 68.6 | 9 | 1.20 (1.07–1.34) | 0.062 | 46.2 | ||
| South America | 2 | 3.12 (1.87–5.20) | < 0.001 | 72.3 | 3 | 1.16 (0.81–1.67) | 0.275 | 22.7 | ||
| Asia | 1 | 1.30 (0.69–2.460 | - | 1 | 1.60 (0.58–4.44) | - | ||||
| Data available | 0.189 | 0.424 | ||||||||
| Self-administered | 12 | 1.25 (1.07–1.45) | 0.002 | 63.5 | 8 | 1.17 (1.03–1.33) | 0.069 | 46.7 | ||
| Interview | 7 | 1.79 (1.16–2.75) | < 0.001 | 78.8 | 11 | 1.09 (0.95–1.26) | 0.052 | 43.7 | ||
| Type of FFQ | 0.294 | 0.857 | ||||||||
| Validated | 16 | 1.44 (1.20–1.75) | < 0.001 | 75.8 | 15 | 1.12 (1.00–1.25) | 0.012 | 49.9 | ||
| Not available | 4 | 1.10 (0.90–1.33) | 0.317 | 15.0 | 4 | 1.17 (0.94–1.44) | 0.172 | 40.0 | ||
| Study quality score | ||||||||||
| High (NOS score > 6) | 16 | 1.32 (1.30–1.54) | < 0.001 | 71.5 | 0.464 | 17 | 1.13 (1.03–1.25) | 0.011 | 48.4 | 0.713 |
| Low (NOS score ≤ 6) | 3 | 1.78 (0.79–4.00) | 0.012 | 77.4 | 2 | 1.03 (0.66–1.63) | 0.177 | 45.1 | ||
| Adjustments | ||||||||||
| BMI, yes | 15 | 1.39 (1.16–1.66) | < 0.001 | 77.4 | 0.705 | 17 | 1.12 (1.01–1.24) | 0.008 | 50.2 | 0.426 |
| no | 4 | 1.22 (0.95–1.57) | 0.842 | 0 | 2 | 1.34 (0.91–1.98) | 0.713 | 0 | ||
| Smoking, yes | 15 | 1.30 (1.11–1.52) | < 0.001 | 73.1 | 0.302 | 15 | 1.12 (1.01–1.25) | 0.006 | 53.4 | 0.979 |
| no | 4 | 1.75 (1.10–2.79) | 0.130 | 47.0 | 4 | 1.17 (0.92–1.50) | 0.441 | 0 | ||
| Energy intake, yes | 8 | 1.21 (1.01–1.46) | < 0.001 | 77.9 | 0.167 | 10 | 1.11 (1.01–1.26) | 0.001 | 65.2 | 0.716 |
| no | 11 | 1.49 (1.15–1.93) | 0.001 | 68.0 | 9 | 1.17 (1.01–1.35) | 0.637 | 0 | ||
| Hypertension, yes | 7 | 1.35 (1.07–1.70) | < 0.001 | 78.7 | 0.929 | 7 | 1.09 (1.00–1.18) | 0.457 | 0 | 0.947 |
| no | 12 | 1.38 (1.10–1.73) | < 0.001 | 68.2 | 12 | 1.13 (0.97–1.32) | 0.009 | 54.6 | ||
| Consumption of vegetables and fruits, yes | 7 | 1.40(1.07–1.85) | < 0.001 | 79.2 | 0.883 | 7 | 1.17 (1.03–1.34) | 0.152 | 34.6 | 0.368 |
| No | 12 | 1.33 (1.09–1.63) | < 0.001 | 67.4 | 12 | 1.08 (0.94–1.24) | 0.012 | 54.5 | ||
| Alcohol, yes | 10 | 1.17 (1.02–1.34) | 0.030 | 51.2 | 0.151 | 11 | 1.15 (1.01–1.30) | 0.002 | 62.4 | 0.635 |
| No | 9 | 1.65 (1.18–2.31) | < 0.001 | 77.2 | 8 | 1.08 (0.94–1.24) | 0.684 | 0 | ||