TABLE 4.

Risk of bias summary: review authors' judgements about each risk of bias item for each included study

First author [ref.]	Methodological quality assessment: randomised controlled trials
	Random sequence generation (selection bias)	Allocation of treatment concealed	Blinding of participants and personnel	Blinding of outcome assessment	Incomplete outcome data	Selective reporting	Other biases (e.g. commercial funding)
Calhoun [13]	U	U	L	U	U	H	H
Honkoop [16]	L	L	H	H	L	L	H
Powell [26]	L	L	L	L	L	L	U
Shaw [25]	L	L	L	U	L	L	L
Smith [24]	U	U	U	U	L	L	H
Syk [14]	L	L	H	H	L	H	H

L: low risk of bias; H: high risk of bias; U: unclear risk of bias.