Table 1. Characteristics of the study population by CIMP status.
| Characteristics | Total (n=1385) | CIMP-low/negative (n=1196) | CIMP-high (n=189) | P-valuea |
|---|---|---|---|---|
| Age, n (%) | ||||
| ⩽65 Years | 501 (36) | 450 (38) | 51 (27) | |
| 66–74 Years | 456 (33) | 401 (34) | 55 (29) | |
| 75+ Years | 428 (31) | 345 (29) | 83 (44) | 0.0001 |
| Sex, n (%) | ||||
| Female | 599 (43) | 495 (41) | 104 (55) | |
| Male | 786 (57) | 701 (59) | 85 (45) | 0.0004 |
| Education, n (%)b | ||||
| Low | 890 (64) | 753 (63) | 137 (73) | |
| Medium | 273 (20) | 241 (20) | 32 (17) | |
| High | 221 (16) | 202 (17) | 19 (10) | 0.0186 |
| Family history of CRC, n (%)c | 212 (15) | 183 (15) | 29 (15) | 0.9940 |
| Lifetime regular active smoking, n (%)d | ||||
| None | 587 (42) | 503 (42) | 84 (44) | |
| <20 Pack-years | 481 (35) | 420 (35) | 61 (32) | |
| 20+ Pack-years | 314 (23) | 270 (23) | 44 (23) | 0.7288 |
| Alcohol consumption, mean (g per day)e | 18.3 | 18.8 | 14.9 | 0.0180 |
| Body mass index, mean (kg m−2)f | 26.5 | 26.5 | 26.8 | 0.2868 |
| Physical activity, mean (lifetime METs, h per week)g | 235.5 | 237.8 | 220.9 | 0.1107 |
| Regular use of NSAIDs, n (%)h | 368 (27) | 321 (27) | 47 (25) | 0.6310 |
| Regular use of statins, n (%)i | 174 (13) | 152 (13) | 22 (12) | 0.6928 |
| Regular use of hormone replacement therapy, n (%)j | 181 (13) | 144 (12) | 37 (20) | 0.0045 |
| Tumour location, n (%) | ||||
| Proximal colon | 492 (36) | 370 (31) | 122 (65) | |
| Distal colon | 375 (27) | 342 (29) | 33 (17) | |
| Rectum | 517 (37) | 483 (40) | 34 (18) | <0.0001 |
| Cancer stage, n (%) | ||||
| I | 255 (18) | 220 (18) | 35 (19) | |
| II | 466 (34) | 391 (33) | 75 (40) | |
| III | 467 (34) | 411 (34) | 56 (30) | |
| IV | 197 (14) | 174 (15) | 23 (12) | 0.2502 |
| No. of invaded lymph node, n (%) | ||||
| ⩽12 | 386 (28) | 345 (29) | 41 (22) | |
| 12–20 | 653 (47) | 572 (48) | 81 (43) | |
| 20+ | 346 (25) | 279 (23) | 67 (35) | 0.0012 |
| Surgery, n (%) | 1378 (99) | 1189 (99) | 189 (100) | 0.2917 |
| Chemotherapy, n (%)k | 626 (45) | 555 (47) | 71 (38) | 0.0200 |
| KRAS mutation, n (%)l | ||||
| Negative | 859 (68) | 731 (68) | 128 (71) | |
| Positive | 402 (32) | 350 (32) | 52 (29) | 0.3524 |
| BRAF mutation, n (%) | ||||
| Negative | 1284 (93) | 1149 (96) | 135 (71) | |
| Positive | 101 (7) | 47 (4) | 54 (29) | <0.0001 |
| Microsatellite instability, n (%) | ||||
| MSS | 1247 (90) | 1137 (95) | 110 (58) | |
| MSI-H | 138 (10) | 59 (5) | 79 (42) | <0.0001 |
Abbreviations: CIMP=CpG island methylator phenotype; CRC=colorectal cancer; MET= metabolic equivalent task; MSI-H=microsatellite instability-high; MSS=microsatellite stable; NSAID=nonsteroidal anti-inflammatory drug.
a
Derived from Pearson's χ2 test of independence between covariables and CIMP status.
b
Missing data for 1 patient.
c
Missing data for 5 patients.
d
Missing data for 3 patients
e
Missing data for 9 patients.
f
Missing data for 8 patients.
g
Missing data for 31 patients..
h
Missing data for 15 patients.
i
Missing data for 3 patients.
j
Missing data for 3 patients.
k
Missing data for 6 patients.
l
Missing data for 124 patients.