Table 2 Risk of bias of included studies
| Random sequence generation | Allocation concealment | Blinding participants/ personnel | Blinding outcome assessment | Incomplete outcome data | Selective reporting | |
|---|---|---|---|---|---|---|
| Carlson 2012; [40] Witte 2011 [41] | Low | Low | High | Low | High | Low |
| Jewkes 2014 [38] | High | High | High | High | Low | Low |
| Jiang 2014 [39] | Low | Unclear | High | High | High | Low |
| L’Engle 2014 [43]; Parcesepe 2016 [44] | Low | Low | High | Unclear | Low | Low |
| Nadkarni 2017a,b [47, 48] | Low | Low | Low | Low | Low | Low |
| Patel 2017 [45]; Weobong 2017 [46] | Low | Low | Low | Low | Low | Low |
| Wechsberg 2013 [42] | Low | Unclear | High | High | Low | Low |
