Table 7.

Risk of bias assessment.

	Random sequence generation	Allocation concealment	Blinding of participants and personnel	Blinding of outcome data	Incomplete outcome data	Selective reporting	Other bias
Svensk et al. (2009)	+	?	–	?	+	+	–
Kalaitzi et al. (2007)	+	?	–	?	+	+	–
Rahmani et al. (2014)	+	?	–	?	+	+	–
Jun et al. (2011)	+	?	–	?	+	+	?
Sebastián et al. (2008)	–	–	–	–	–	+	+
Crane-Okada et al. (2012)	+	?	–	?	–	+	?
Sherman et al. (2018)	+	?	+	?	–	+	?

“+”, low risk of bias; “?”, unclear risk of bias; “–”, High-risk of bias.