Table 4.
Rotating night shift work duration and incident colorectal cancer by tumor anatomical site (NHS: 1988–2012)
| No. of cases (N = 1,341)5 | RR (95% CI)1 | p‐trend1 , 3 | RR (95% CI)2 | p‐trend2 , 3 | |
|---|---|---|---|---|---|
| NHS baseline rotating night shift work history in years4 | |||||
| Colon combined | |||||
| Never | 403 | 1.0 (ref) | 1.0 (ref) | ||
| 1–14 | 542 | 1.02 (0.90, 1.16) | 1.02 (0.90, 1.16) | ||
| 15+ | 93 | 1.11 (0.89, 1.40) | 0.45 | 1.09 (0.87, 1.37) | 0.62 |
| 1038 | |||||
| Proximal colon | |||||
| Never | 271 | 1.0 (ref) | 1.0 (ref) | ||
| 1–14 | 347 | 0.98 (0.83, 1.14) | 0.98 (0.83, 1.14) | ||
| 15+ | 57 | 1.02 (0.76, 1.36) | 0.98 | 1.00 (0.75, 1.34) | 0.90 |
| 675 | |||||
| Distal colon | |||||
| Never | 132 | 1.0 (ref) | 1.0 (ref) | ||
| 1–14 | 195 | 1.12 (0.89, 1.39) | 1.12 (0.90, 1.40) | ||
| 15+ | 36 | 1.32 (0.91, 1.92) | 0.21 | 1.27 (0.87, 1.85) | 0.32 |
| 363 | |||||
| Rectum | |||||
| Never | 111 | 1.0 (ref) | 1.0 (ref) | ||
| 1–14 | 156 | 1.07 (0.83, 1.36) | 1.05 (0.82, 1.34) | ||
| 15+ | 36 | 1.68 (1.15, 2.46) | 0.01 | 1.60 (1.09, 2.34) | 0.02 |
| 303 |
1
Adjusted for age and follow‐up cycle.
2
See footnote Table 2.
3
p‐trend was calculated using the midpoint of each category of rotating shift work duration in years (1–2, 3–4, 5–9, 10–14, 15–19, 20–29, 30+).
4
Categories of shift work duration (Never, 1–14 years, 15+ years) were used to compare with our previously published results.
5
The numbers of colon and rectal cancers may not be equal to total number of colorectal cancers because, in some cases, the specific cancer site was unknown.