Table 2.
Subgroup analysis.
| Subgroup | No of Study | Effect Size | 95% CI | p-Value | I2 | Q-Value | p-Value | τ2 |
|---|---|---|---|---|---|---|---|---|
| All studies [7,8,18,19,20,21,22,23,24,25,26,27,28] | 13 | 1.80 | 1.46–2.22 | <0.001 | 85.71 | 91.03 | <0.001 | 0.12 |
| Study design | ||||||||
| Cohort [7,8,18,22,23,24,25,28] | 8 | 1.99 | 1.37–2.88 | <0.001 | 88.08 | 58.74 | <0.001 | 0.23 |
| Case-control [7,19,20,21,26,27] | 6 | 1.69 | 1.34–2.13 | <0.001 | 80.33 | 25.42 | <0.001 | 0.06 |
| Region | ||||||||
| Asia [8,18,20,21,22,25] | 6 | 2.07 | 1.29–3.30 | 0.002 | 91.40 | 58.18 | <0.001 | 0.28 |
| Europe [7,23,24,27,28] | 5 | 1.87 | 1.41–2.48 | <0.001 | 77.43 | 22.16 | <0.001 | 0.09 |
| North America [19,26] | 2 | 1.27 | 0.94–1.72 | 0.11 | 70.27 | 3.36 | 0.06 | 0.03 |
| Methodological quality | ||||||||
| High [7,8,19,22,28] | 5 | 1.31 | 1.06–1.63 | 0.01 | 74.86 | 19.89 | 0.001 | 0.04 |
| Moderate [18,20,21,23,24,25,26] | 7 | 2.32 | 1.74–3.09 | <0.001 | 78.16 | 27.47 | <0.001 | 0.10 |
| Low [27] | 1 | 2.18 | 1.57–3.03 | <0.001 | - | - | - | - |
| Adjusted for age | ||||||||
| Yes [7,8,21,22,23,24,25,27] | 8 | 2.01 | 1.46–2.75 | <0.001 | 89.86 | 78.91 | <0.001 | 0.18 |
| No [18,19,20,26,28] | 5 | 1.54 | 1.22–1.95 | <0.001 | 66.98 | 12.11 | 0.01 | 0.04 |
| Adjusted for gender | ||||||||
| Yes [7,8,22,23,24,25,27] | 7 | 1.94 | 1.40–2.69 | <0.001 | 88.53 | 61.02 | <0.001 | 0.17 |
| No [18,19,20,21,26,28] | 6 | 1.70 | 1.30–2.21 | <0.001 | 80.01 | 25.02 | <0.001 | 0.08 |
| Adjusted for smoking | ||||||||
| Yes [7,8,19,27] | 4 | 1.33 | 1.02–1.73 | 0.03 | 88.65 | 24.47 | <0.001 | 0.07 |
| No [18,20,21,22,23,24,25,26,28] | 9 | 2.17 | 1.71–2.76 | <0.001 | 74.37 | 31.22 | <0.001 | 0.08 |
| Adjusted for alcohol | ||||||||
| Yes | 4 | 1.33 | 1.02–1.73 | 0.03 | 88.65 | 24.47 | <0.001 | 0.07 |
| No | 9 | 2.17 | 1.71–2.76 | <0.001 | 74.37 | 31.22 | <0.001 | 0.08 |
| Adjusted for GERD | ||||||||
| Yes [7,8,18,19,20,21,22,23,27] | 9 | 1.84 | 1.39–2.44 | <0.001 | 89.25 | 83.73 | <0.001 | 0.17 |
| No [24,25,26,28] | 4 | 1.66 | 1.31–2.10 | <0.001 | 51.32 | 6.16 | 0.10 | 0.02 |
| Adjusted for aspirin | ||||||||
| Yes [7,8,18,22,23] | 5 | 1.85 | 1.26–2.71 | 0.001 | 89.80 | 49.01 | <0.001 | 0.18 |
| No [19,20,21,24,25,26,27,28] | 8 | 1.78 | 1.42–2.23 | <0.001 | 75.91 | 29.06 | <0.001 | 0.07 |
| Number of PPI users | ||||||||
| ≤5000 [7,19,20,21,22,25,26,27] | 8 | 1.74 | 1.41–2.14 | <0.001 | 75.08 | 32.10 | <0.001 | 0.06 |
| >5000 [8,18,23,24,28] | 5 | 1.96 | 1.20–3.18 | 0.006 | 91.77 | 48.64 | <0.001 | 0.26 |
| Lag time | ||||||||
| <=6 months [22,25,26] | 3 | 1.46 | 1.03–2.05 | 0.03 | 74.25 | 7.76 | 0.02 | 0.06 |
| >6 months [7,8,18,19,20,21,23,24,28] | 9 | 1.86 | 1.43–2.43 | <0.001 | 88.56 | 78.67 | <0.001 | 0.15 |
| Cancer type | ||||||||
| Cardia [7,21,22,23,26,27] | 6 | 1.32 | 0.84–2.03 | 0.21 | 58.92 | 12.17 | 0.03 | 0.18 |
| Non-cardia [7,21,22,23,26,27] | 6 | 2.38 | 1.90–2.98 | <0.001 | 0 | 4.86 | 0.43 | 0 |