Table 1.
Disease characteristics of study population.
| Ulcerative colitis | Crohn's disease | All patients | |
|---|---|---|---|
| Number of patients | 257 | 237 | 494 |
| Male : female (% female) |
124 : 133 (51.8%) |
117 : 120 (50.6%) |
241 : 253 (51.2%) |
| Ethnic group | |||
| Caucasian | 191 (74.3%) | 198 (83.5%) | 389 (78.7%) |
| Asian | 41 (15.9%) | 29 (12.2%) | 70 (14.2%) |
| Afro-Caribbean | 11 (4.3%) | 4 (1.7%) | 15 (3.0%) |
| Other | 14 (5.4%) | 6 (2.5%) | 20 (4.0%) |
| Age at diagnosis (years) | |||
| Mean (st. error) | 39.5 (1.05) | 35.1 (1.09) | 37.4 (0.76) |
| Range (median) | 8–82 (35) | 10–82 (30) | 8–82 (33) |
| P = 0.0041 | |||
| Age group at diagnosis | |||
| A1 < 17 | 7 (2.7%) | 17 (7.2%) P = 0.034 | 24 (4.9%) |
| A2 17–40 | 145 (56.4%) | 142 (59.9%) | 287 (58.1%) |
| A3 > 40 | 105 (40.9%) | 78 (32.9%) | 183 (37.0%) |
| Smoking status | |||
| Nonsmoker | 234 (91.1%) | 182 (77.3%) | 416 (84.2%) |
| Smoker | 23 (8.9%) | 55 (22.7%) | 78 (15.8%) |
| P < 0.0001 | |||
| Appendectomy | |||
| Negative | 167 (88.8%) | 139 (78.5%) | 306 (84.3%) |
| Positive | 21 (11.1%) | 38 (21.5%), P = 0.0101 | 59 (15.7%) |
| Unknown | 69 | 60 | 129 |
| Family history of IBD | |||
| Positive | 51 (19.8%) | 45 (19.0%) | 96 (19.4%) |
| Negative | 206 (80.2%) | 192 (81.0%) | 398 (80.6%) |
| Family history of colorectal cancer | |||
| Positive | 29 (12.4%) | 21 (9.8%) | 50 (11.2%) |
| Negative | 205 (87.6%) | 193 (90.2%) | 398 (88.8%) |
| Unknown | 23 | 23 | 46 |
| History of IBD surgery | |||
| Positive | 14 (8.0%) | 88 (41.5%) P < 0.0001 | 102 (26.4%) |
| Negative | 161 (92.0%) | 124 (58.5%) | 285 (73.6%) |
| Unknown | 82 | 25 | 107 |
| Disease location | |||
| Ileal | N/A | 37 (17.5%) | N/A |
| Ileocolonic | N/A | 124 (58.8%) | N/A |
| Colonic | N/A | 50 (23.7%) | N/A |
| Unknown | N/A | 26 | N/A |
| Disease behaviour | |||
| Inflammatory | N/A | 139 (63.5%) | N/A |
| Stenotic | N/A | 34 (15.6%) | N/A |
| Fistulating | N/A | 46 (21.6%) | N/A |
| Unknown | N/A | 18 | N/A |
All comparisons between UC and CD group were calculated with Fisher's exact test, with the exception of mean age at diagnosis where nonpaired t-test analysis was conducted. % calculated from patients with data only (i.e., unknown data excluded from % calculations).