Table 2.
Association of potential risk factors with background rate of colorectal cancer by anatomical site
| Colon | ||||||||
|---|---|---|---|---|---|---|---|---|
| Total colon | Proximal | Distal | Rectum | |||||
| Lifestyle and BMI | Relative risk | (95% CI) | Relative risk | (95% CI) | Relative risk | (95% CI) | Relative risk | (95% CI) |
| Smoking | ||||||||
| Pack‐years at age 70 | 1.28 | (1.10; 1.48) | 1.11 | (0.89; 1.39) | 1.33 | (1.08; 1.64) | 1.04 | (0.85; 1.29) |
| Men, unknown smoking status | 0.70 | (0.53; 0.93) | 0.45 | (0.29; 0.69) | 1.09 | (0.74; 1.60) | 1.02 | (0.73; 1.42) |
| Alcohol drinking | ||||||||
| Amount, drink/day | 1.06 | (1.02; 1.10) | 1.04 | (0.98; 1.10) | 1.08 | (1.03; 1.14) | 1.08 | (1.03; 1.14) |
| Men, unknown drinking status | 1.17 | (0.90; 1.54) | 0.99 | (0.65; 1.50) | 1.27 | (0.87; 1.86) | 0.82 | (0.59; 1.12) |
| Women, unknown drinking status | 0.67 | (0.55; 0.81) | 0.64 | (0.48; 0.84) | 0.79 | (0.59; 1.06) | 0.73 | (0.56; 0.94) |
| BMI | ||||||||
| 0–18.5 | 0.83 | (0.69; 0.99) | 0.73 | (0.55; 0.96) | 0.97 | (0.75; 1.25) | 1.00 | (0.79; 1.26) |
| 18.5–25 | Reference | Reference | Reference | Reference | ||||
| 25+ | 1.21 | (1.05; 1.39) | 1.28 | (1.05; 1.56) | 1.20 | (0.97; 1.48) | 1.08 | (0.88; 1.3) |
| Unknown | 1.51 | (1.28; 1.79) | 1.58 | (1.23; 2.01) | 1.46 | (1.14; 1.88) | 1.38 | (1.11; 1.71) |
| Meat | ||||||||
| None or less than 1 day/week | 1.04 | (0.90; 1.19) | 0.98 | (0.80; 1.20) | 1.08 | (0.87; 1.34) | 0.97 | (0.79; 1.20) |
| 2–4 days/week | Reference | Reference | Reference | Reference | ||||
| Almost every day | 0.98 | (0.83; 1.16) | 0.93 | (0.73; 1.17) | 1.06 | (0.83; 1.35) | 1.05 | (0.83; 1.32) |
| Unknown | 1.14 | (0.98; 1.31) | 1.09 | (0.88; 1.34) | 1.05 | (0.84; 1.32) | 1.38 | (1.13; 1.68) |
Total colon cancer includes proximal, distal and other colon cancers. BMI was calculated as weight (kg)/height (m2).