Bias Domains and Questions	RCT	Prospective observational
Selection Bias
Was administered dose or exposure level adequately randomised?	X *
Was allocation to study groups adequately concealed?	X
Confounding Bias
Did the study design or analysis account for important confounding?		X *
Performance Bias
Were the research personnel and human subjects blinded to the study group during the study?	X
Attrition/Exclusion Bias
Were outcome data complete without attrition or exclusion from analysis?	X	X
Detection Bias
Can we be confident in the exposure characterisation?	X *	X *
Can we be confident in the outcome assessment?	X *	X *
Selective Reporting Bias
Were all measured outcomes reported?	X	X
Other Sources of Bias
Were there no other potential threats to internal validity?	X
Were the statistical methods applied appropriate?		X

* Key question.