Table 2. Subgroup analyses of the association between cholecystectomy and the risk of colorectal cancer, stratified by sex, geographic region, lag period, study quality, and time interval since cholecystectomy.
| Group | Subgroup | RR (95% CI) | Test for overall effect (P value) | No. of studies | Heterogeneity I2, % |
|---|---|---|---|---|---|
| Sex | Male | 1.13 (0.87–1.46) | 0.365 | 10 | 94.9 |
| Female | 1.13 (0.91–1.41) | 0.274 | 10 | 92.8 | |
| Geographic region | USA | 1.30 (0.95–1.78) | 0.101 | 1 | 0.0 |
| Europe | 1.07 (0.99–1.16) | 0.071 | 11 | 70.7 | |
| Asia | 1.16 (0.77–1.76) | 0.471 | 6 | 98.0 | |
| Lag period | Lag period | 1.11 (0.94–1.31) | 0.238 | 12 | 96.6 |
| No lag period | 1.14 (0.92–1.43) | 0.237 | 6 | 73.9 | |
| Study quality | High | 1.09 (0.94–1.26) | 0.243 | 13 | 90.0 |
| Moderate or low | 1.18 (0.91–1.55) | 0.215 | 5 | 97.3 | |
| Time interval since cholecystectomy | |||||
| 1–4 years | CC | 1.25 (0.90–1.73) | 0.178 | 3 | 91.5 |
| RC | 1.28 (0.94–1.73) | 0.112 | 3 | 84.4 | |
| ≥5 years | CC | 1.06 (0.98–1.15) | 0.124 | 3 | 0.0 |
| RC | 0.96 (0.82–1.12) | 0.572 | 3 | 44.1 | |
RR, relative risk; CI, confidential interval; CC, colon cancer; RC, rectal cancer.