Table 2 Risk of bias in included studies
Study | Randomization process | Deviation from intended intervention | Missing outcome data | Measurement of outcomes | Selection of reported result | Overall risk of bias |
|---|---|---|---|---|---|---|
Xu et al. [15] | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
Solheim et al. [14] | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
Rohktabnak et al. [16] | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
Kim et al. [23] | Some concerns | Low risk | Low risk | Some concerns | Low risk | Some concerns |
Vintar et al. [22] | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
Calmet et al. [21] | Some concerns | Low risk | Low risk | Low risk | Low risk | Some concerns |