Table 1.
Summary risk estimates of the association between cruciferous vegetable (CV) consumption and gastric cancer risk
| No. of studies | Summary RR (95% CI) | Q statistic | I‐square value (%) | P h * | P h ** | |
|---|---|---|---|---|---|---|
| Overall studies | ||||||
| CV | 22 | 0.81 (0.75–0.88) | 27.27 | 12.0 | 0.292 | – |
| Cabbage | 7 | 0.68 (0.58–0.80) | 5.77 | 0 | 0.449 | |
| Subgroup analyses for CV | ||||||
| High quality studies (scores ≥7) | 11 | 0.84 (0.76–0.93) | 8.29 | 0 | 0.824 | 0.437 |
| Study design | ||||||
| Prospective studies | 6 | 0.89 (0.77–1.02) | 3.42 | 0 | 0.755 | 0.179 |
| Case–control studies | 16 | 0.78 (0.71–0.86) | 21.75 | 21.8 | 0.195 | |
| Type of control subjects | ||||||
| Population based | 5 | 0.74 (0.64–0.87) | 3.65 | 0 | 0.724 | 0.491 |
| Hospital based | 11 | 0.81 (0.72–0.90) | 17.44 | 42.7 | 0.065 | |
| Geographic location | ||||||
| Europe | 11 | 0.82 (0.74–0.92) | 11.70 | 14.6 | 0.305 | 0.877 |
| North America | 5 | 0.82 (0.70–0.95) | 5.36 | 6.8 | 0.373 | |
| Asia | 6 | 0.79 (0.69–0.92) | 10.05 | 30.3 | 0.186 | |
| Gender | ||||||
| Male | 4 | 0.78 (0.64–0.96) | 3.03 | 1.0 | 0.387 | 0.787 |
| Female | 4 | 0.82 (0.66–1.00) | 1.54 | 0 | 0.673 | |
| Lauren's classification | ||||||
| Intestinal | 3 | 0.77 (0.56–1.05) | 3.15 | 36.5 | 0.207 | 0.469 |
| Diffuse | 3 | 0.93 (0.66–1.30) | 0.21 | 0 | 0.900 | |
| Anatomic subsite | ||||||
| Cardia | 4 | 0.84 (0.65–1.09) | 4.51 | 33.5 | 0.211 | 0.914 |
| Non‐cardia | 6 | 0.86 (0.74–0.99) | 7.16 | 2.3 | 0.412 | |
| Adjustment for confounders or risk factors | ||||||
| Vegetables/fruit intake | ||||||
| Yes | 4 | 0.88 (0.55–1.42) | 9.62 | 68.8 | 0.022 | 0.431 |
| No | 18 | 0.81 (0.75–0.88) | 17.96 | 0 | 0.590 | |
| Smoking status | ||||||
| Yes | 15 | 0.81 (0.74–0.89) | 11.92 | 0 | 0.750 | 0.977 |
| No | 7 | 0.87 (0.68–1.11) | 16.04 | 56.3 | 0.025 | |
| Alcohol drinking | ||||||
| Yes | 7 | 0.81 (0.72–0.91) | 6.02 | 0.3 | 0.421 | 0.894 |
| No | 15 | 0.83 (0.75–0.92) | 22.01 | 22.8 | 0.184 | |
| Salted food | ||||||
| Yes | 2 | 0.83 (0.63–1.11) | 0.92 | 0 | 0.339 | 0.867 |
| No | 20 | 0.82 (0.76–0.89) | 27.24 | 19.2 | 0.202 | |
| Total energy intake | ||||||
| Yes | 13 | 0.86 (0.78–0.95) | 13.12 | 0 | 0.593 | 0.076 |
| No | 9 | 0.76 (0.67–0.86) | 12.54 | 36.2 | 0.129 | |
| Education/socioeconomic status | ||||||
| Yes | 12 | 0.85 (0.77–0.94) | 16.87 | 17.0 | 0.263 | 0.256 |
| No | 10 | 0.79 (0.70–0.89) | 10.41 | 13.5 | 0.319 | |
| Subgroup analyses for cabbage | ||||||
| High quality studies (scores ≥7) | 2 | 0.77 (0.56–1.06) | 0.27 | 0 | 0.607 | 0.426 |
| Study design | ||||||
| Prospective studies | 2 | 0.77 (0.56–1.06) | 0.27 | 0 | 0.607 | 0.426 |
| Case–control studies | 5 | 0.66 (0.55–0.79) | 4.76 | 15.9 | 0.313 | |
*P‐value for heterogeneity within each subgroup; **P‐value for heterogeneity between subgroups with meta‐regression analysis. –, not applicable, CI, confidence interval; RR, relative risk.