Table 2.

Risk of Bias Assessment of Included Studies

Study	Focused Issue?	Appropriate Methodology?	Appropriate Recruitment of Patients?	Appropriate Recruitment of Controls?	Exposure Accurately Measured?	Control of Confounding Factors?	Precision of Results?	Statistics Clearly Reported?	Generalizability of Results?	Results Fit With Other Evidence?
Alfredson et al11 (1998)	Yes	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	Yes
Alfredson et al40 (1998)	Yes	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	Yes
Alfredson et al41 (1998)	Yes	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	Yes
Alfredson et al46 (1996)	Yes	Yes	No	Yes	Yes	Yes	No	Yes	Yes	Yes
Azevedo et al42 (2009)	Yes	Yes	No	Yes	Yes	Yes	No	Yes	Yes	Yes
Baur et al53 (2004)	Yes	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	Yes
Becker et al50 (2017)	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Child et al13 (2010)	Yes	Yes	No	No	Yes	Yes	Yes	Yes	Yes	Yes
Firth et al43 (2010)	Yes	Yes	Yes	Yes	No	Yes	No	Yes	No	No
Grigg et al51 (2013)	Yes	Yes	Yes	No	Yes	Yes	No	No	Yes	Yes
Haglund-Åkerlind and Eriksson39 (1993)	Yes	Yes	No	No	No	Yes	No	Yes	Yes	No
Maquirriain44 (2012)	Yes	Yes	Yes	Yes	Yes	Yes	No	Yes	No	No
Masood et al48 (2014)	Yes	Yes	Yes	Yes	No	Yes	No	Yes	No	No
Mayer et al54 (2007)	Yes	Yes	No	Yes	No	Yes	Yes	Yes	No	Yes
McCrory et al49 (1999)	Yes	Yes	Yes	No	No	Yes	No	No	Yes	No
Öhberg et al47 (2001)	Yes	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	Yes
Silbernagel et al19 (2006)	Yes	Yes	Yes	No	Yes	Yes	No	Yes	Yes	Yes
Wang et al52 (2012)	Yes	Yes	Yes	Yes	No	Yes	Yes	Yes	Yes	Yes
Wang et al45 (2011)	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	No