Shapiro 1998 d.

Methods	Same as Shapiro 1998b
Participants	Same as Shapiro 1998b ANALYSED: N = 52
Interventions	Same as Shapiro 1998b
Outcomes	Same as Shapiro 1998b
Notes	Same as Shapiro 1998b
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information on sequence generation
Allocation concealment (selection bias)	Unclear risk	Insufficient information
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Blinding of participants and key study personnel ensured
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Blinding of participants and key study personnel ensured
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data
Selective reporting (reporting bias)	Low risk	Study protocol not available but published reports include all expected outcomes, including those that were prespecified
Other bias	Low risk	Study apparently free of other sources of bias