Table 3. Standardised incidence ratios (SIR) using age- and gender-specific incidence rates—Overall and by subgroups.
| Total observations | O | E | SIR | 95% CI | |
|---|---|---|---|---|---|
| Overall risk | 403,998 | 2992 | 3253.20 | 0.92 | 0.88–0.95 |
| Risk by gender: | |||||
| Female | 218,776 | 1275 | 1355.90 | 0.94 | 0.89–0.99 |
| Male | 185,222 | 1717 | 1897.29 | 0.90 | 0.86–0.94 |
| Risk by age-group: | |||||
| 40–49 | 88,846 | 198 | 186.61 | 1.06 | 0.92–1.22 |
| 50–59 | 133,856 | 800 | 824.73 | 0.97 | 0.90–1.04 |
| 60–69 | 181,296 | 1994 | 2241.86 | 0.89 | 0.85–0.93 |
| Combined model—10-year risk | |||||
| Quintile 1 (lowest) | 80,368 | 166 | 199.63 | 0.83 | 0.71–0.96 |
| Quintile 2 | 80,575 | 374 | 446.53 | 0.83 | 0.75–0.92 |
| Quintile 3 | 80,753 | 552 | 679.77 | 0.81 | 0.74–0.88 |
| Quintile 4 | 80,958 | 757 | 868.69 | 0.87 | 0.81–0.93 |
| Quintile 5 (highest) | 81,344 | 1143 | 1058.57 | 1.08 | 1.01–1.14 |
| Combined model—Full lifetime risk | |||||
| Quintile 1 (lowest) | 80,568 | 366 | 543.82 | 0.67 | 0.60–0.74 |
| Quintile 2 | 80,727 | 526 | 614.98 | 0.85 | 0.78–0.93 |
| Quintile 3 | 80,762 | 561 | 657.90 | 0.85 | 0.78–0.92 |
| Quintile 4 | 80,849 | 648 | 694.81 | 0.93 | 0.86–1.00 |
| Quintile 5 (highest) | 81,092 | 891 | 741.70 | 1.20 | 1.12–1.28 |
| By number of affected first-degree relatives | |||||
| 0 | 358,981 | 2544 | 2857.48 | 0.89 | 0.85–0.92 |
| 1 | 42,541 | 412 | 371.93 | 1.10 | 1.00–1.22 |
| 2 | 2,409 | 35 | 23.02 | 1.52 | 1.09–2.11 |
| Combined model—10-year risk: (No first-degree family history) | |||||
| Quintile 1 (lowest) | 71,412 | 124 | 171.16 | 0.72 | 0.60–0.86 |
| Quintile 2 | 71,616 | 329 | 383.60 | 0.85 | 0.77–0.95 |
| Quintile 3 | 71,753 | 465 | 592.75 | 0.78 | 0.71–0.86 |
| Quintile 4 | 71,951 | 664 | 767.75 | 0.86 | 0.80–0.93 |
| Quintile 5 (highest) | 72,249 | 962 | 942.22 | 1.02 | 0.95–1.08 |
| Top 10% | 36,189 | 546 | 499.22 | 1.09 | 1.00–1.19 |
| Top 5% | 18,126 | 305 | 259.97 | 1.17 | 1.04–1.31 |
| Bottom 10% | 35,680 | 36 | 63.30 | 0.56 | 0.41–0.78 |
| Bottom 5% | 17,836 | 14 | 26.90 | 0.52 | 0.30–0.87 |
| Combined model—Full lifetime risk: (no first-degree family history) | |||||
| Quintile 1 (lowest) | 71,621 | 333 | 479.16 | 0.69 | 0.62–0.77 |
| Quintile 2 | 71,725 | 438 | 541.21 | 0.81 | 0.73–0.88 |
| Quintile 3 | 71,782 | 494 | 579.08 | 0.85 | 0.78–0.93 |
| Quintile 4 | 71,834 | 547 | 609.60 | 0.89 | 0.82–0.97 |
| Quintile 5 (highest) | 72,019 | 732 | 648.44 | 1.12 | 1.05–1.21 |
| Top 10% | 36,051 | 408 | 330.10 | 1.23 | 1.12–1.36 |
| Top 5% | 18,035 | 214 | 167.53 | 1.27 | 1.11–1.46 |
| Bottom 10% | 35,795 | 151 | 229.02 | 0.66 | 0.56–0.77 |
| Bottom 5% | 17,901 | 79 | 111.42 | 0.71 | 0.56–0.88 |
SIR was calculated based on number of cases observed and expected using sex-specific UK population rates of colorectal cancer incidence rates, calculated for the entire eligible UK Biobank cohort or by gender, age group or by family history status, and stratified by full lifetime and 10-year risk categories for the combined model. Abbreviations: O = observed, E = expected.