Table 1.
Baseline characteristics of colorectal cancer screening population by outcome of polyps or high-risk adenomas (n=2548)
| n | Polyps | High-risk adenomas | |||
| No n=1450 (57%) |
Yes n=1098 (43%) |
No n=2359 (93%) |
Yes n=189 (7%) |
||
| Demographics | |||||
| Age (years) | |||||
| <40 | 34 | 27 (2%) | 7 (1%) | 33 (1%) | 1 (1%) |
| 40–49 | 102 | 70 (5%) | 32 (3%) | 96 (4%) | 6 (3%) |
| 50–59 | 1169 | 713 (49%) | 456 (42%) | 1104 (47%) | 65 (34%) |
| 60+ | 1243 | 1450 (44%) | 603 (55%) | 1126 (48%) | 117 (62%) |
| p*<0.01 | p<0.01 | ||||
| Sex | |||||
| Female | 1163 | 775 (63%) | 388 (35%) | 1113 (47%) | 50 (26%) |
| Male | 1385 | 675 (47%) | 710 (65%) | 1246 (53%) | 139 (74%) |
| p<0.01 | p<0.01 | ||||
| Ethnicity | |||||
| Non-white | 358 | 213 (15%) | 145 (13%) | 328 (14%) | 30 (16%) |
| White | 2190 | 1237 (85%) | 953 (87%) | 2031 (86%) | 159 (84%) |
| p=0.29 | p=0.45 | ||||
| BMI (kg/m2) | |||||
| <25 | 853 | 540 (37%) | 313 (29%) | 810 (34%) | 43 (23%) |
| 25–30 | 1129 | 638 (44%) | 491 (45%) | 1035 (44%) | 94 (50%) |
| 30+ | 566 | 272 (19%) | 294 (27%) | 514 (22%) | 52 (28%) |
| p<0.01 | p<0.01 | ||||
| Family and personal health | |||||
| Smoking | |||||
| Never | 1339 | 834 (58%) | 505 (46%) | 1261 (53%) | 78 (41%) |
| Former | 1011 | 535 (37%) | 476 (43%) | 930 (39%) | 81 (43%) |
| Current | 198 | 81 (6%) | 117 (11%) | 168 (7%) | 30 (16%) |
| p<0.01 | p<0.01 | ||||
| Reason for colonoscopy | |||||
| Average risk | 2067 | 1223 (84%) | 844 (77%) | 1945 (82%) | 122 (65%) |
| FIT+/FOBT+ | 209 | 66 (5%) | 143 (13%) | 161 (7%) | 48 (25%) |
| Family history | 272 | 161 (11%) | 111 (10%) | 253 (11%) | 19 (10%) |
| p<0.01 | p<0.01 | ||||
| Lifetime NSAIDs | |||||
| NSAID use | |||||
| Never | 946 | 513 (35%) | 433 (39%) | 850 (36%) | 96 (51%) |
| Ever | 1135 | 937 (65%) | 665 (61%) | 1509 (64%) | 93 (49%) |
| p=0.04 | p<0.01 | ||||
| NSAID use frequency | |||||
| No regular use | 946 | 513 (43%) | 433 (47%) | 850 (43%) | 96 (60%) |
| Monthly | 406 | 245 (20%) | 161 (18%) | 383 (20%) | 23 (14%) |
| Weekly | 292 | 162 (14%) | 130 (14%) | 273 (14%) | 19 (12%) |
| Daily | 465 | 272 (23%) | 193 (21%) | 442 (23%) | 23 (14%) |
| p=0.15 | p<0.01 | ||||
| Daily dose-years of NSAID use† | |||||
| None | 946 | 0 (0) | 0 (0) | 0 (0) | 0 (0) |
| T1 | 333 | 0.06 (0.06) | 0.05 (0.05) | 0.06 (0.06) | 0.06 (0.05) |
| T2 | 669 | 0.45 (0.21) | 0.44 (0.19) | 0.45 (0.20) | 0.47 (0.22) |
| T3 (high) | 600 | 4.53 (6.70) | 4.77 (5.84) | 4.60 (6.23) | 5.27 (8.43) |
| p=0.05 | p<0.01 | ||||
| Dietary fibre intake | |||||
| Total fibreठ| |||||
| Q1 (low) | 548 | 11.01 (2.58) | 10.51 (2.65) | 10.87 (2.60) | 10.00 (2.78) |
| Q2 | 545 | 16.75 (1.41) | 16.98 (1.34) | 16.84 (1.39) | 16.85 (1.34) |
| Q3 | 549 | 22.14 (1.91) | 22.04 (1.75) | 22.10 (1.85) | 22.11 (1.90) |
| Q4 (high) | 552 | 33.88 (8.23) | 33.59 (8.89) | 33.83 (8.54) | 32.58 (6.67) |
| p=0.51 | p=0.09 | ||||
| Soluble fibreঠ| |||||
| Q1 (low) | 547 | 3.69 (0.86) | 3.61 (0.87) | 3.68 (0.85) | 3.38 (0.99) |
| Q2 | 551 | 5.61 (0.46) | 5.66 (0.46) | 5.63 (0.46) | 5.56 (0.49) |
| Q3 | 545 | 7.32 (0.59) | 7.33 (0.56) | 7.32 (0.58) | 7.35 (0.53) |
| Q4 (high) | 551 | 11.17 (2.79) | 11.32 (3.20) | 11.22 (2.96) | 11.16 (2.45) |
| p=0.08 | p=0.06 | ||||
| Insoluble fibre‡** | |||||
| Q1 (low) | 547 | 7.16 (1.68) | 6.79 (1.77) | 7.04 (1.71) | 6.61 (1.83) |
| Q2 | 545 | 11.02 (0.99) | 11.14 (0.89) | 11.06 (0.95) | 11.10 (0.90) |
| Q3 | 548 | 14.72 (1.23) | 14.70 (1.22) | 14.72 (1.22) | 14.63 (1.28) |
| Q4 (high) | 554 | 22.67 (5.54) | 22.58 (5.79) | 22.69 (5.69) | 21.55 (4.08) |
| p=0.39 | p=0.09 | ||||
*p-Values from Pearson’s χ2 test of independence.
†Tertile cut-offs for NSAID use were: 4.5×10−5–00.164, 0.165–0.894 and ≥0.904 daily dose-years.
‡Missing questionnaire data on fibre intake lead to reduced sample size (n=2194).
§Quartile cut-offs for total dietary fibre intake were: ≤14.3, 14.31–19.14, 19.15–25.51 and ≥25.52 g/day.
¶Quartile cut-offs for dietary insoluble fibre intake were: ≤9.36, 9.37–12.72, 12.73–16.96 and ≥16.98 g/day.
**Quartile cut-offs for dietary soluble fibre intake were: ≤4.83, 4.84–6.42, 6.43–8.44 and ≥8.45 g/day.
BMI, body mass index; FIT, faecal immunochemical test; FOBT, faecal occult blood test; NSAIDs, non-steroidal anti-inflammatory drugs.