Table 3. The summary of review authors’ judgments about each risk of bias item for included studies.

Study	Random sequence generation	Allocation concealment	Blinding	Incomplete outcome data	Selective reporting	Other bias	Overall
Garcia et al. (2006) [24]	L	L	L	L	L	U	Good
Antal et al. (2010) [20]	H	L	U	L	L	U	Poor
Beck et al. (2010) [22]	L	U	L	U	L	U	Fair
Li et al. (2010) [28]	L	L	L	L	L	U	Good
Dewulf et al. (2012) [23]	U	L	L	H	L	U	Fair
Hashizume et al. (2012) [26]	L	L	L	L	L	U	Good
Maki et al. (2012) [29]	L	U	L	H	L	U	Fair
Reimer et al. (2013) [33]	U	U	L	U	L	U	Poor
Wanders et al. (2013) [37]	L	U	L	U	L	U	Poor
Kobayakawa et al. (2013) [27]	U	U	L	U	L	U	Poor
Geliebter et al. (2014) [25]	L	L	L	L	L	U	Good
Nishimura et al. (2015) [30]	L	U	U	U	L	U	Poor
Upadhyaya et al. (2015) [36]	L	U	U	H	L	U	Poor
Aoe et al. (2017) [21]	L	L	U	U	L	U	Fair
Parnell et al. (2017) [31]	U	L	L	L	L	U	Good
Strączkowski et al. (2018) [35]	L	L	U	U	L	U	Fair
Sakai et al. (2019) [34]	U	L	U	L	L	U	Good
Reimer et al. (2020) [32]	L	U	L	L	L	U	Good

H, high risk of bias; L, low risk of bias; U, unclear or unrevealed risk of bias.