9. Methodological quality of nonexperimental case‐control studies.
| Study | Selection | Comparability | Exposure | Total (out of 9) | ||||||
| S1 | S2 | S3 | S4 | C1 | C2 | E1 | E2 | E3 | ||
| Bandera 2010 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
| Berroukche 2012 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 8 |
| Bonner 2005 | a(1) | a(1) | a(1) | b(0) | 1 | 1 | c(0) | a(1) | a(1) | 7 |
| Chen 2011 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 8 |
| Chen 2015 in: Chen 2017a | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 9 |
| Chen 2016 in: Chen 2017a | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 8 |
| Chen 2017a | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 8 |
| Fu 2013 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 8 |
| Gao 1994 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 7 |
| Gao 2005 | a(1) | a(1) | a(1) | a(1) | 1 | 0 | b(1) | a(1) | c(0) | 7 |
| Gavrilas 2018 | a(1) | a(1) | c(0) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 7 |
| Goodman 2003 | a(1) | a(1) | a(1) | a(1) | 1 | 0 | b(1) | a(1) | a(1) | 8 |
| Goto 1990 | a(1) | a(1) | a(1) | b(0) | 1 | 1 | b(1) | a(1) | c(0) | 7 |
| Green 2014 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
| Hakim 2000 | a(1) | a(1) | a(1) | a(1) | 1 | 0 | b(1) | a(1) | a(1) | 8 |
| Han 2008 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
| Hemelt 2010 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 7 |
| Hoshiyama 1992 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
| Hsu 2012 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
| Huang 1999 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | b(0) | 7 |
| Inoue 1994 in: Huang 1999 | a(1) | a(1) | b(0) | a(1) | 1 | 0 | d(0) | a(1) | a(1) | 6 |
| Inoue 1998 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | d(0) | a(1) | a(1) | 7 |
| Inoue 2008 | a(1) | a(1) | a(1) | a(1) | 1 | 0 | b(1) | a(1) | c(0) | 7 |
| Islami 2009 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | b(0) | 8 |
| Iwasaki 2014 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | b(0) | 7 |
| Ji 1996 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
| Ji 1997 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | b(0) | 8 |
| Jia 2016 | a(1) | a(1) | a(1) | a(1) | 1 | 0 | c(0) | a(1) | a(1) | 7 |
| Jian 2004 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 8 |
| Jin 2013 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 9 |
| Kakuta 2009 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 8 |
| Kato 1990 | a(1) | b(0) | a(1) | a(1) | 1 | 0 | d(0) | a(1) | a(1) | 6 |
| Kato 1990a in: Huang 1999 | a(1) | b(0) | b(0) | a(1) | 1 | 0 | d(0) | a(1) | a(1) | 5 |
| Kono 1988a | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | b(0) | b(0) | 7 |
| Kono 1988b | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | b(0) | b(0) | 6 |
| Kubik 2004 in: Kubik 2008 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 7 |
| Kubik 2008 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 7 |
| Kuo 2009 | a(1) | a(1) | a(1) | a(1) | 0 | 0 | b(1) | a(1) | c(0) | 6 |
| Lassed 2016 | a(1) | a(1) | b(0) | a(1) | 0 | 0 | b(1) | a(1) | a(1) | 6 |
| Le Marchand 2000 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 9 |
| Lee 2017 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 7 |
| Lei 1994 | c(0) | b(0) | b(0) | a(1) | 1 | 0 | e(0) | a(1) | c(0) | 3 |
| Leung 2016 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 9 |
| Li 2011aa | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
| Li 2011ab | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 7 |
| Li 2011b in: Mu 2003 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
| Li 2014 | a(1) | a(1) | a(1) | a(1) | 1 | 0 | b(1) | a(1) | b(0) | 7 |
| Li 2016 | a(1) | a(1) | b(0) | a(1) | 1 | 0 | b(1) | a(1) | a(1) | 7 |
| Lin 2012 | a(1) | a(1) | b(0) | a(1) | 1 | 0 | b(1) | a(1) | b(0) | 6 |
| Liu 2010 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 9 |
| Liu 2017 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 8 |
| Mao 2011 | a(1) | a(1) | b(0) | b(0) | 1 | 1 | b(1) | a(1) | b(0) | 6 |
| Mizoo 2013 | a(1) | a(1) | b(0) | a(1) | 1 | 0 | b(1) | a(1) | a(1) | 7 |
| Mizuno 1992 | a(1) | a(1) | b(0) | a(1) | 1 | 0 | b(1) | a(1) | b(0) | 6 |
| Mu 2003 | a(1) | b(0) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 7 |
| Mu 2005 in: Mu 2003 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
| Nagle 2010 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
| Oze 2014 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | b(0) | 8 |
| Peng 2013 | a(1) | a(1) | a(1) | a(1) | 1 | 0 | b(1) | a(1) | b(0) | 7 |
| Peng 2015 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | b(0) | 8 |
| Ruan 2010 | a(1) | a(1) | b(0) | a(1) | 1 | 0 | b(1) | a(1) | a(1) | 7 |
| Setiawan 2001 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
| Shrubsole 2009 | a(1) | a(1) | a(1) | a(1) | 1 | 0 | b(1) | a(1) | b(0) | 7 |
| Song 2008 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | b(0) | 8 |
| Sonoda 2004 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | b(0) | 7 |
| Tajima 1985 | a(1) | a(1) | b(0) | a(1) | 1 | 0 | b(1) | a(1) | b(0) | 6 |
| Takezaki 2000 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 8 |
| Takezaki 2001 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 8 |
| Tewes 1990 | b(0) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | b(0) | 7 |
| Tse 2017 | a(1) | a(1) | b(0) | a(1) | 1 | 0 | b(1) | a(1) | b(0) | 6 |
| Wakai 2004 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 8 |
| Wang 1999 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | e(0) | a(1) | c(0) | 7 |
| Wang 2006 | a(1) | a(1) | a(1) | a(1) | 0 | 0 | b(1) | a(1) | b(0) | 6 |
| Wang 2007 | a(1) | a(1) | a(1) | a(1) | 1 | 0 | b(1) | a(1) | b(0) | 7 |
| Wang 2012a | a(1) | a(1) | b(0) | a(1) | 1 | 0 | b(1) | a(1) | c(0) | 6 |
| Wang 2012b | a(1) | a(1) | b(0) | a(1) | 1 | 0 | b(1) | a(1) | a(1) | 7 |
| Wang 2012c | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
| Wang 2013a | a(1) | a(1) | b(0) | a(1) | 1 | 0 | b(1) | a(1) | a(1) | 7 |
| Wang 2013b | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 7 |
| Wang 2015 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 7 |
| Wilkens 1996 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
| Wu 2003 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 9 |
| Wu 2009a | a(1) | b(0) | b(0) | a(1) | 1 | 0 | b(1) | a(1) | c(0) | 5 |
| Wu 2009b | a(1) | b(0) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 8 |
| Xu 2007 | a(1) | a(1) | a(1) | a(1) | 1 | 0 | b(1) | a(1) | a(1) | 8 |
| Xu 2013 | c(0) | b(0) | c(0) | a(1) | 1 | 0 | b(1) | a(1) | c(0) | 4 |
| Yan 2016 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
| Ye 1998 | a(1) | a(1) | a(1) | a(1) | 1 | 0 | b(1) | a(1) | b(0) | 7 |
| Yu 1995 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
| Zhang 2002 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | b(0) | 7 |
| Zhang 2007 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | a(1) | 8 |
| Zhang 2008 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | b(0) | 7 |
| Zheng 1993 | a(1) | a(1) | b(0) | a(1) | 1 | 1 | b(1) | a(1) | b(0) | 7 |
| Zhong 2001 | a(1) | a(1) | a(1) | a(1) | 1 | 1 | b(1) | a(1) | c(0) | 8 |
aPopulation controls considered; bHospital controls considered.