Subgroup | Studies (n) | OR (95%CI) | I2 (%) | P value |
---|---|---|---|---|
Total | 8 | 1.62 (1.18, 2.23) | 82.3 | < 0.01 |
Design | ||||
Case-control study | 5 | 1.79 (1.12, 2.86) | 88.4 | < 0.01 |
Cohort study | 3 | 1.42 (1.09, 1.85) | 0 | < 0.01 |
Location | ||||
Asia | 3 | 1.66 (0.90, 3.08) | 91.3 | 0.10 |
Europe | 3 | 1.52 (1.20, 1.92) | 0 | < 0.01 |
North America | 2 | 2.09 (1.18, 3.69) | 0 | 0.01 |
Risk of bias | ||||
Low | 3 | 1.41 (0.89, 2.25) | 90 | 0.14 |
Moderate | 5 | 1.66 (0.90, 3.08) | 2.8 | < 0.01 |
No. of cases | ||||
< 500 | 4 | 2.08 (1.60, 2.70) | 0 | < 0.01 |
> 500 | 4 | 1.33 (0.99, 1.79) | 73.9 | 0.06 |