Table 2.
Relative risks (RRs) and 95% confidence intervals (CIs) between selected risk factors and risk of colorectal cancer
| Risk factors | RR (95% CI) | Sources | ||
|---|---|---|---|---|
| Men | Women | Design | ||
| Smoking | 1.16 (1.09–1.24) | 1.16 (1.09–1.24) | Meta-analysis | 30 |
| Alcohol drinking | 1.24 (1.01–1.54) | 1.24 (1.01–1.54) | Cohort study | 31 |
| Overweight | 1.25 (1.07–1.45) | 1.25 (1.07–1.45) | Cohort study | 32 |
| Obesity | 1.57 (1.23–2.00) | 1.57 (1.23–2.00) | ||
| Physical inactivity | 1.32 (1.23–1.41) | 1.27 (1.17–1.41) | Meta-analysis | 33 |
| Vegetable intakea: Urban | 12 | |||
| Quintile 5 | 1.00 | 1.00 | ||
| Quintile 4 | 1.12 (1.04–1.19) | 1.10 (1.03–1.16) | ||
| Quintile 3 | 1.20 (1.06–1.34) | 1.18 (1.05–1.30) | ||
| Quintile 2 | 1.30 (1.09–1.51) | 1.27 (1.08–1.46) | ||
| Quintile 1 | 1.52 (1.14–1.95) | 1.46 (1.13–1.83) | ||
| Vegetable intakea: rural | Meta-analysis | 12 | ||
| Quintile 5 | 1.00 | 1.00 | ||
| Quintile 4 | 1.12 (1.04–1.19) | 1.10 (1.03–1.16) | ||
| Quintile 3 | 1.21 (1.06–1.35) | 1.19 (1.06–1.31) | ||
| Quintile 2 | 1.30 (1.09–1.52) | 1.27 (1.08–1.46) | ||
| Quintile 1 | 1.50 (1.14–1.92) | 1.46 (1.13–1.83) | ||
| Fruit intakea: urban | Meta-analysis | 12 | ||
| Quintile 5 | 1.00 | 1.00 | ||
| Quintile 4 | 1.04 (1.01–1.07) | 1.05 (1.02–1.09) | ||
| Quintile 3 | 1.06 (1.02–1.11) | 1.07 (1.02–1.13) | ||
| Quintile 2 | 1.09 (1.03–1.15) | 1.10 (1.03–1.17) | ||
| Quintile 1 | 1.12 (1.04–1.21) | 1.13 (1.04–1.23) | ||
| Fruit intakea: rural | Meta-analysis | 12 | ||
| Quintile 5 | 1.00 | 1.00 | ||
| Quintile 4 | 1.06 (1.02–1.10) | 1.09 (1.03–1.15) | ||
| Quintile 3 | 1.07 (1.02–1.12) | 1.11 (1.03–1.19) | ||
| Quintile 2 | 1.09 (1.03–1.16) | 1.13 (1.04–1.23) | ||
| Quintile 1 | 1.12 (1.04–1.20) | 1.16 (1.05–1.28) | ||
| Red and processed meata: urban | Meta-analysis | 11 | ||
| Quintile 1 | 1.00 | 1.00 | ||
| Quintile 2 | 1.07 (1.02–1.11) | 1.04 (1.01–1.07) | ||
| Quintile 3 | 1.12 (1.03–1.20) | 1.09 (1.03–1.15) | ||
| Quintile 4 | 1.17 (1.05–1.29) | 1.14 (1.04–1.24) | ||
| Quintile 5 | 1.27 (1.07–1.48) | 1.22 (1.06–1.38) | ||
| Red and processed meata: rural | Meta-analysis | 11 | ||
| Quintile 1 | 1.00 | 1.00 | ||
| Quintile 2 | 1.04 (1.01–1.07) | 1.04 (1.01–1.07) | ||
| Quintile 3 | 1.08 (1.02–1.14) | 1.07 (1.02–1.11) | ||
| Quintile 4 | 1.12 (1.03–1.21) | 1.12 (1.03–1.20) | ||
| Quintile 5 | 1.20 (1.06–1.34) | 1.17 (1.05–1.29) | ||
aRRs were first transformed onto a log scale and divided by 100 to give the log RR/g per day, then multiplied by the lower intake in each quintile, finally, the RRs in other quintiles were divided by that in quintile 5 (vegetable and fruit) or quintile 1 (red and processed meat) to get the final RRs, and the RR in quintile 5 (vegetable and fruit) or quintile 1 (red and processed meat) was assumed to be equal to 1