Table 3 Risk of colorectal cancer according to time since single or most recent negative colonoscopy.
| History of screening colonoscopy | Odds ratio (95% CI) | |||
|---|---|---|---|---|
| Cases | Controls | Adjusted for age and sex | Adjusted for multiple covariates* | |
| (n = 380) | (n = 485) | |||
| No previous colonoscopy | 350 (92.1%) | 351 (72.4%) | 1.00 Reference | 1.00 Reference |
| Single or multiple colonoscopies, last negative colonoscopy, any age | ||||
| Any time ago | 30 (7.9%) | 134 (27.6%) | 0.22 (0.14 to 0.34) | 0.26 (0.16 to 0.40) |
| 1–2 years ago | 7 (1.8%) | 50 (10.3%) | 0.13 (0.06 to 0.30) | 0.16 (0.07 to 0.36) |
| 3–4 years ago | 8 (2.1%) | 31 (6.4%) | 0.26 (0.12 to 0.58) | 0.29 (0.13 to 0.68) |
| 5–9 years ago | 5 (1.3%) | 23 (4.7%) | 0.21 (0.08 to 0.57) | 0.25 (0.09 to 0.69) |
| 10–19 years ago | 5 (1.3%) | 17 (3.5%) | 0.29 (0.11 to 0.80) | 0.33 (0.12 to 0.91) |
| 20+ years ago | 5 (1.3%) | 13 (2.7%) | 0.38 (0.13 to 1.09) | 0.46 (0.16 to 1.32) |
| Single negative colonoscopy, any age | ||||
| Any time ago | 22 (5.8%) | 83 (17.1%) | 0.27 (0.16 to 0.43) | 0.30 (0.18 to 0.50) |
| 1–4 years ago | 8 (2.1%) | 41 (8.5%) | 0.19 (0.09 to 0.42) | 0.21 (0.09 to 0.47) |
| 5+ years ago | 14 (3.7%) | 42 (8.7%) | 0.33 (0.18 to 0.62) | 0.39 (0.21 to 0.73) |
| Multiple colonoscopies, last negative colonoscopy, any age | ||||
| Any time ago | 7 (1.8%) | 50 (10.3%) | 0.14 (0.06 to 0.31) | 0.16 (0.07 to 0.37) |
| 1–4 years ago | 6 (1.6%) | 39 (8.0%) | 0.15 (0.06 to 0.36) | 0.18 (0.07 to 0.44) |
| 5+ years ago | 1 (0.3%) | 11 (2.3%) | 0.09 (0.01 to 0.69) | 0.11 (0.01 to 0.84) |
| Single or multiple colonoscopies, last negative colonoscopy <55 years | ||||
| Any time ago | 13 (3.4%) | 38 (7.8%) | 0.35 (0.18 to 0.66) | 0.45 (0.23 to 0.88) |
| 1–4 years ago | 4 (1.1%) | 10 (2.1%) | 0.51 (0.16 to 1.66) | 0.58 (0.17 to 1.93) |
| 5+ years ago | 9 (2.4%) | 28 (5.8%) | 0.34 (0.16 to 0.73) | 0.41 (0.19 to 0.90) |
| Single or multiple colonoscopies, last negative colonoscopy 55–64 years | ||||
| Any time ago | 7 (1.8%) | 49 (10.1%) | 0.14 (0.06 to 0.32) | 0.17 (0.08 to 0.39) |
| 1–4 years ago | 4 (1.1%) | 29 (6.0%) | 0.15 (0.05 to 0.42) | 0.18 (0.06 to 0.51) |
| 5+ years ago | 3 (0.8%) | 20 (4.1%) | 0.14 (0.04 to 0.49) | 0.17 (0.05 to 0.58) |
| Single or multiple colonoscopies, last negative colonoscopy 65+ years | ||||
| Any time ago | 10 (2.6%) | 47 (9.7%) | 0.21 (0.11 to 0.42) | 0.21 (0.10 to 0.44) |
| 1–4 years ago | 7 (1.8%) | 42 (8.7%) | 0.14 (0.06 to 0.33) | 0.16 (0.07 to 0.39) |
| 5+ years ago | 3 (0.8%) | 5 (1.0%) | 0.46 (0.11 to 1.99) | 0.51 (0.12 to 2.21) |
*Adjusted for age, sex, education, participation in general health screening examination, family history of colorectal cancer, smoking, body mass index, ever regular use of NSAIDs, ever regular use of HRT.
CI, confidence interval; HRT, hormone replacement therapy; NSAID, non‐steroidal anti‐inflammatory drug.