Table 1. Risk of bias assessment for prospective studies.

	Rooth et al 17	Sanna et al 16
Selection bias
Random sequence generation	+	+
Allocation concealment	+	+
Performance bias
Blinding of participants and personnel	+	+
Detection bias
Blinding of outcome assessment	+	+
Attrition bias
Incomplete outcome data addressed	–	?
Reporting bias
Selective reporting	–	–

+High risk; –Low risk; ? Unclear risk.