1. Methodological quality assessment.

Study	Method of allocation concealment described and appropriate	Study described as 'randomized'	Method of randomization described and appropriate	Study described as 'double blind'	Method of blinding described and appropriate	# and reason for withdrawals described in each group
Cibere 2004	M	M	M	M	M	M
Clegg 2006	M	M	M	M	M	NM
Crolle 1980	NM	M	NM	M	M	NM
D'ambrosio 1981	NM	M	NM	M	M	NM
Drovanti 1980	NM	M	NM	M	M	NM
Herrero‐Beaumont 2007	M	M	M	M	M	M
Houpt 1999	M	M	NM	M	M	NM
Hughes 2002	M	M	M	M	M	M
McAlindon 2004	M	M	M	M	M	M
Mehta 2007	NM	M	NM	M	M	M
Muller‐FassBender 94	M	M	M	M	M	M
Noack 1994	M	M	M	M	M	M
Pavelka 2002	M	M	M	M	M	M
Pujalte 1980	NM	M	NM	M	M	M
Qiu 1998	NM	M	NM	M	M	M
Qiu 2005	NM	M	NM	NM	NM	M
Reginster 2001	M	M	M	M	NM	M
Reichelt 1994	NM	M	NM	M	M	M
Rindone 2000	NM	M	M	M	NM	NM
Rovati 1997	M	M	M	M	M	M
Rozendaal 2008	M	M	M	M	M	M
Usha 2004	NM	M	NM	M	M	M
Vajaradul 1981	NM	M	NM	M	M	M
Vaz 1982	NM	M	NM	M	NM	M
Zenk 2002	M	M	NM	M	M	M

M = criteria met; NM = criteria not met