Table 3.
Risk of bias summary for the included studies
| Study | Random sequence generation | Allocation concealment | Blinding of participants | Blinding of personnel | Blinding of outcome assessors | Incomplete outcome data | Selective reporting | Other potential sources of bias |
|---|---|---|---|---|---|---|---|---|
| Barreto et al. (2019) [14] | Low risk | Low risk | Low risk | Low risk | Unclear risk | Low risk | Low risk | Low risk |
| Cai et al. (2019) [15] | Low risk | Unclear risk | Unclear risk | Unclear risk | Low risk | Low risk | Low risk | Low risk |
| Ibrahim et al. (2019) [26] | High risk | Unclear risk | High risk | High risk | Unclear risk | Low risk | Low risk | Low risk |
| Ilhanli et al. (2015) [16] | Low risk | Unclear risk | High risk | High risk | Low risk | Low risk | Low risk | Low risk |
| Jeyaraman et al. (2018) [29] | High risk | High risk | High risk | High risk | Unclear risk | Low risk | Low risk | Low risk |
| Kesikburun et al. (2013) [17] | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Kothari et al. (2017) [18] | Low risk | High risk | High risk | High risk | Low risk | Low risk | Low risk | Low risk |
| Nejati et al. (2017) [19] | Low risk | Low risk | High risk | High risk | Low risk | Low risk | Low risk | Low risk |
| Pasin et al. (2019) [20] | Unclear risk | Unclear risk | High risk | High risk | Low risk | Low risk | Low risk | Low risk |
| Rha et al. (2013) [21] | Low risk | Low risk | Low risk | Low risk | Low risk | High risk | Low risk | Low risk |
| Sari and Eroglu (2020) [22] | Low risk | Unclear risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Schwitzguebel et al. (2019) [23] | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Shams et al. (2016) [24] | Low risk | Low risk | High risk | High risk | High risk | Unclear risk | Low risk | Low risk |
| Šmíd et al. (2018) [27] | Low risk | Unclear risk | Unclear risk | Unclear risk | Unclear risk | Low risk | Low risk | Low risk |
| Upadhyay et al. (2020) [28] | Low risk | Low risk | High risk | High risk | Low risk | Low risk | Low risk | Low risk |
| Wesner et al. (2016) [11] | Unclear risk | High risk | Unclear risk | Unclear risk | Unclear risk | High risk | High risk | Low risk |
| Wongworawat (2013) [25] | Unclear risk | Unclear risk | Unclear risk | Unclear risk | Unclear risk | High risk | High risk | Unclear risk |