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.