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Quality assessment of the included studies in meta-analysis
| Study | Risk of bias assessment | |||
|---|---|---|---|---|
| Selection (0-4) |
Comparability (0-2) |
Exposure (0-3) |
Quality score | |
| Apopa et al. | 3 | 2 | 3 | 8 |
| Nejman et al. | 3 | 1 | 3 | 7 |
| Yu et al. | 3 | 1 | 3 | 7 |
| Kovaleva et al. | 3 | 2 | 3 | 8 |
