Table 2 The results of risk of bias assessments

Randomized controlled trials

 Francony G. 2008

Yes

Yes

Yes

Yes

No

UC

Yes

Yes

Yes

Yes

Yes

Yes

Yes

 Vialet R. 2003

UC

Yes

Yes

UC

No

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

 Cottenceau V. 2011

Yes

Yes

Yes

Yes

UC

UC

Yes

Yes

Yes

Yes

Yes

Yes

Yes

 Jagannatha AT. 2017

Yes

Yes

Yes

Yes

UC

UC

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Cross-sectional studies

 Ware M. 2005

Yes

Yes

Yes

Yes

No

No

Yes

Yes

–

–

–

–

–

 Cheng F. 2018

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

–

–

–

–

–

Case–control study

 Carter C. 2017

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

–

–

–

–

Quasi-experimental study

 Schatzmann C. 1998

Yes

N/A

N/A

No

UC

N/A

N/A

Yes

UC

–

–

–

–