Standardised incidence ratios and 95% CI of developing Crohn’s disease by time since appendectomy stratified by Crohn’s disease extent
| Time since appendectomy (years) | Crohn’s ileitis SIR (95% CI) | Ileocolonic Crohn’s disease SIR (95% CI) | Crohn’s colitis SIR (95% CI) | Other and unspecifiedCrohn’s disease SIR (95% CI) |
|---|---|---|---|---|
| SIR, standardised incidence ratio. | ||||
| <0.5 | 14.14 (11.00 to 18.18) | 8.43 (4.99 to 14.23) | 9.46 (6.10 to 14.66) | 6.87 (5.04 to 9.36) |
| 0.5–<1 | 4.09 (2.57 to 6.48) | 1.77 (0.57 to 5.49) | 2.79 (1.25 to 6.21) | 4.05 (2.71 to 6.04) |
| 1–4 | 1.84 (1.46 to 2.32) | 1.57 (1.04 to 2.36) | 1.61 (1.13 to 2.30) | 2.28 (1.90 to 2.73) |
| 5–9 | 1.16 (0.90 to 1.48) | 1.61 (1.15 to 2.27) | 1.29 (0.92 to 1.81) | 1.47 (1.22 to 1.78) |
| 10–14 | 1.25 (0.99 to 1.58) | 0.81 (0.50 to 1.30) | 0.56 (0.36 to 0.92) | 1.05 (0.85 to 1.31) |
| 15–19 | 0.76 (0.54 to 1.06) | 1.03 (0.64 to 1.66) | 1.02 (0.69 to 1.50) | 1.15 (0.92 to 1.44) |
| ⩾20 | 1.01 (0.74 to 1.38) | 1.35 (0.86 to 2.11) | 0.83 (0.54 to 1.29) | 1.17 (0.94 to 1.47) |