Clinical characteristics of included patients
| Serial sampling study | Cohort study Time point analysis | Cohort study Survival analysis | |||
| Cohort 1 | Cohort 2 | Cohort 1 | Cohort 2 | ||
| n | 92 | 2006 | 2100 | 1687 | 1848 |
| Sampling years | 2012–2016 | 2001–2006 | 2009–2017 | 2001–2006 | 2009–2017 |
| Age (years) | 67.1 (64.4–69.9) | 60.1 (60.6–61.6) | 67.2 (66.7–67.7) | 61.5 (61.0–62.0) | 67.6 (67.1–68.1) |
| Gender (M) | 51 (55%) | 1137 (57%) | 1172 (56%) | 970 (57%) | 1024 (55%) |
| BMI (kg/m2) | 26.1 (24.8–27.5) | 26.6 (26.4–26.8) | 27.5 (27.3–27.7) | 26.6 (26.4–26.8) | 27.6 (27.4–27.9) |
| Cancer site | |||||
| Colon | 62 (67%) | 1153 (57%) | 1313 (63%) | 962 (57%) | 1161 (63%) |
| Rectum | 30 (33%) | 829 (41%) | 761 (36%) | 714 (42%) | 687 (37%) |
| NA | 0 | 24 (1%) | 56 (3%) | 11 (1%) | 0 (0%) |
| Cancer stage | |||||
| AJCC 1 | 27 (29%) | 383 (19%) | 415 (20%) | 383 (22%) | 415 (22%) |
| AJCC 2 | 31 (34%) | 666 (33%) | 692 (33%) | 666 (39%) | 692 (37%) |
| AJCC 3 | 21 (23%) | 638 (32%) | 741 (35%) | 638 (38%) | 741 (40%) |
| AJCC 4 | 7 (8%) | 268 (13%) | 167 (8%) | 0† | 0† |
| NA | 6 (7%) | 51 (3%) | 85 (4%) | 0 | 0 |
| ‘raw’ 25OHD (nmol/L) | NA* | 29.3 (28.4–30.2) | 46.5 (45.3–47.6) | 29.1 (28.1–30.1) | 46.0 (44.7–47.4) |
| May-adjusted 25OHD (nmol/L) | NA* | 33.9 (33.0–34.8) | 51.7 (50.5–52.8) | 28.8 (27.82–29.7) | 52.1 (50.9–53.4) |
| Tertile 1 | NA* | <18.5 | <37.32 | <18.1 | <38.0 |
| Tertile 2 | NA* | 18.5–34.0 | 37.3–56.5 | 18.1–33.1 | 38.0–57.9 |
| Tertile 3 | NA* | >34.0 | >56.46 | >33.1 | >57.9 |
| Sample time point | |||||
| Preoperative (months) | NA* | 0 (0%) | 560 (27%) | 0 (0%) | 486 (26%) |
| 0–12 | NA* | 1798 (90%) | 549 (26%) | 1517 (90%) | 471 (26%) |
| 12–24 | NA* | 180 (9%) | 396 (19%) | 147 (9%) | 351 (19%) |
| >24 | NA* | 28 (1%) | 595 (28%) | 23 (1%) | 540 (29%) |
| Season of sample | |||||
| Winter | NA* | 489 (24%) | 573 (27%) | 408 (24%) | 517 (28%) |
| Spring | NA* | 524 (26%) | 563 (27%) | 449 (27%) | 483 (26%) |
| Summer | NA* | 465 (23%) | 434 (21%) | 392 (23%) | 378 (20%) |
| Autumn | NA* | 528 (26%) | 530 (25%) | 438 (26%) | 470 (25%) |
| Follow-up (days) | NA* | NA | NA | 4841 | 1318 |
| Survival | |||||
| Alive | NA* | NA | NA | 978 (58%) | 1637 (89%) |
| Dead | NA* | NA | NA | 709 (42%) | 211 (11%) |
| CRC death | NA* | NA | NA | 421 (25%) | 138 (7%) |
Age at time of surgery given. Pre-illness BMI reported where available. Mean values given for summary variables except follow-up (median censored follow-up given). ‘Raw’ 25OHD was not adjusted for seasonal variation, that is, not ‘May-adjusted’.
*Repeated measures.
†AJCC 4 excluded from survival analysis.
25OHD, 25-hydroxyvitamin D; AJCC, American Joint Committee on Cancer; BMI, body mass index; CRC, C-reactive protein; NA, not applicable.