Table 1. Meta-analysis of risk estimates of dietary methionine intake (highest versus lowest) and risk of incident colorectal cancer.
| Number of studies | References | RR (95 % CI) |
Heterogeneity test |
|||
|---|---|---|---|---|---|---|
| Random-effect model | Fix-effects model | P | I 2 (%) | |||
| All studies | 8 | 12-18 | 0.89 (0.77-1.03) | 0.89 (0.79-1.00) | 0.18 | 29.1 |
| Follow-up | ||||||
| ＞10 years | 5 | 12,15,16,17 | 0.81 (0.70-0.95) | 0.82 (0.71-0.94) | 0.33 | 13.6 |
| ＜10 years | 3 | 13,14,18 | 1.08 (0.87-1.34) | 1.08 (0.87-1.34) | 0.48 | 0.0 |
| Number of cases | ||||||
| ＞500 | 4 | 12,14-16 | 0.89 (0.74-1.08) | 0.89 (0.76-1.03) | 0.24 | 26.0 |
| ＜500 | 4 | 13,17,18 | 0.89 (0.69-1.15) | 0.89 (0.75-1.07) | 0.12 | 49.4 |
| Areas | ||||||
| Asian | 2 | 14,18 | 1.19 (0.90-1.57) | 1.19 (0.90-1.57) | 0.53 | 0.0 |
| Western | 6 | 12,13,15-17 | 0.83 (0.73-0.95) | 0.83 (0.73-0.95) | 0.40 | 3.9 |
| Sex | ||||||
| Men | 3 | 12,14,17 | 0.75 (0.57-0.99) | 0.75 (0.58-0.97) | 0.31 | 15.2 |
| Women | 7 | 12-18 | 0.94 (0.80-1.09) | 0.93 (0.82-1.06) | 0.23 | 26.3 |
| Subsites | ||||||
| Colon | 4 | 12,17,25 | 0.77 (0.64-0.92) | 0.77 (0.64-0.92) | 0.58 | 0.0 |
| Rectal | 2 | 12,25 | 0.88 (0.55-1.42) | 0.89 (0.58-1.38) | 0.31 | 15.3 |
RR, relative risk; CI, confidence interval.