Table 3. Quality assessment of included studies.
| Author | Random Sequence generation | Allocation concealment | Blinding of participants and personnel | Blinding of outcome assessment | Incomplete outcome data | Selective outcome reporting |
|---|---|---|---|---|---|---|
| Arbeille et al. 2012 | ? | ? | ? | ? | + | - |
| Beller et al. 2011 | ? | ? | ? | ? | + | + |
| Bosutti et al. 2016 | ? | ? | ? | ? | ? | + |
| Florian et al. 2015 | ? | ? | ? | ? | - | + |
| Lee et al. 2014 | - | ? | ? | ? | - | + |
| Rejc et al. 2015 | NA | NA | NA | NA | + | + |
| Schneider et al. 2009 | ? | ? | ? | ? | + | - |
| S. Trappe et al. 2008 | ? | ? | ? | ? | ? | - |
| T.A Trappe et al. 2007 | ? | ? | ? | ? | + | + |
| Zwart et al. 2005 | ? | ? | ? | ? | + | - |
Assessment of risk of bias in the 10 studies included. ‘NA’ indicates that assessment was not applicable due to study type. ‘+’ indicates low risk, ‘-‘ indicates high risk and ‘?’ indicates unclear risk/no information.