Supplementary Table 3a Risk of Bias Assessment Using the CASP Tool of the Included Case-Control Studies

Case-Control Study / Did the study address a clearly focused issue? / Did the authors use an appropriate method to answer their question / Were the cases recruited in an acceptable way? / Were the controls selected in an acceptable way? / Was the exposure accurately measured to minimize bias? / Have authors taken account of potential confounding factors in design and analysis? / Do you believe in the results? / Can the results be applied to local population? / Do the results of this study fit with other available evidence? / TOTAL
Ahmed et al. 2012 / Yes / Yes / Can’t tell / Can’t tell / No / No / No / No / Can’t tell / 2
Ajrouche et al. 2015 / Yes / Yes / Yes / Yes / Yes / Yes / Yes / Yes / Yes / 9
Ateyah et al. 2017 / Yes / Yes / Can’t tell / Can’t tell / No / No / No / No / Can’t tell / 2
Canfield et al. 2004 / Yes / Yes / Yes / Yes / Yes / Yes / Yes / Yes / Yes / 9
Cardwell et al. 2008 / Yes / Yes / Yes / Yes / Yes / No / No / Yes / Yes / 7
Chan et al. 2002 / Yes / No / Yes / No / No / No / No / No / Yes / 3
Chang et al. 2012 / Yes / Yes / Yes / Yes / Yes / No / No / No / No / 5
Conceicao Nunes et al. 2016 / Yes / Yes / Yes / No / Yes / No / Yes / No / Yes / 6
Dockerty et al. 1999 / Yes / Yes / Yes / Yes / No / No / Yes / Yes / Yes / 7
Flores-Lujano et al. 2009 / Yes / Yes / Yes / No / No / No / No / No / No / 3
Ibrahem et al. 2014 / Yes / Yes / Can’t tell / Can’t tell / No / No / No / No / Can’t tell / 2
Jourdan-Da Silva et al. 2004 / Yes / Yes / Yes / Yes / No / No / No / No / Yes / 5
Kerr et al. 2003 / Yes / Yes / Can’t tell / No / Yes / No / No / No / Can’t tell / 3
Loutfy et al. 2006 / Yes / No / Can’t tell / No / No / No / No / No / Can’t tell / 1
Ma et al. 2005 / Yes / Yes / Yes / Yes / Yes / Yes / Yes / Yes / Yes / 9
MacArthur et al. 2008 / Yes / Yes / Yes / Yes / Yes / Yes / Yes / Yes / Yes / 9
MacKenzie et al. 2001 / Yes / Yes / Can’t tell / Can’t tell / Yes / No / No / No / Can’t tell / 3
Mahjour et al. 2009 / Yes / Yes / Can’t tell / Can’t tell / Yes / No / No / No / Can’t tell / 3
McKinney et al. 1987 / Yes / Yes / Can't tell / Can't tell / Can't tell / No / No / No / No / 2
McKinney et al. 1999 / Yes / Yes / Yes / Yes / Yes / No / Yes / Yes / Yes / 8
Neglia et al. 2000 / Yes / Yes / Yes / Yes / Can't tell / No / No / No / No / 4
Nishi et al. 1989 / No / No / Yes / No / No / No / No / No / No / 1
Paltiel et al. 2006 / Yes / Yes / Can't tell / Yes / Can't tell / Can't tell / No / No / No / 3
Perrillat et al. 2002 / Yes / Yes / Yes / Yes / Yes / No / Yes / No / Yes / 7
Petridou et al. 2001 / Yes / Yes / No / No / Yes / Yes / Yes / No / Yes / 6
Roman et al. 2007 / Yes / Yes / Yes / Yes / Yes / No / Yes / Yes / Yes / 8
Rosenbaum et al. 2005 / Yes / Yes / Yes / Yes / No / Yes / Yes / No / Yes / 7
Rudant et al. 2010 / Yes / Yes / Yes / Yes / No / No / Yes / Yes / Yes / 7
Rudant et al. 2015 / Yes / Yes / Yes / Yes / No / No / Yes / Yes / Yes / 7
Salonen et al. 2002 / No / Yes / Can’t tell / Can’t tell / Yes / No / No / No / Can’t tell / 2
Schlehofer et al. 1996 / Yes / Yes / Yes / No / No / No / No / No / No / 3
Schuz et al. 1999 / Yes / Yes / Yes / No / No / No / Yes / No / Yes / 5
Surico and Muggeo 2005 / Yes / Yes / Can’t tell / Can’t tell / No / No / No / No / Can’t tell / 2
Tesse et al. 2009 / Yes / Yes / Can’t tell / Can’t tell / Yes / No / No / No / Can’t tell / 3
Till et al. 1979 / No / No / Yes / No / No / No / No / Yes / Can't tell / 2
van Steensel-Moll et al. 1986 / Yes / Yes / Yes / Yes / No / No / Can't tell / No / Yes / 5
Zaki and Ashray 2010 / No / No / Yes / No / Yes / No / Can’t tell / No / Can’t tell / 2
Zaki et al. 2006 / Yes / Yes / Can’t tell / No / Yes / No / Can’t tell / No / Can’t tell / 3

Supplementary Table 3b Risk of Bias Assessment Using the CASP Tool of the Included Cohort Studies

Study / Did the study address a clearly focused issue? / Were the cohort recruited in an acceptable way? / Was the exposure accurately measured to minimize bias? / Was the outcome accurately measured to minimize bias? / Have the authors identified all important confounding factors? / Have authors taken account of the confounding factors in design and/or analysis? / Was the follow up of subjects complete enough? / Was the follow up of subjects long enough? / Do you believe the results? / Can the results be applied to the local population? / Do the results of the study fit with other available evidence? / TOTAL
Lin et al. 2015 / Yes / Yes / Yes / Yes / No / Yes / Yes / Yes / Yes / No / Yes / 9
Vestergaard et al. 2013 / Yes / Yes / Yes / Yes / No / Yes / Yes / Yes / Yes / Yes / Yes / 10