Study	Yr	Bias due to confounding	Bias in selection of participants into the study	Bias in classification of interventions	Bias in deviations from intended Interventions	Bias due to missing data	Bias in measurement of outcomes	Bias in selection of the reported result	Overall bias
Ahrens [16]	2005	Critical	Critical	NI	NI	Low	Serious	Low	Critical
Ahrens [17]	2007	Critical	Serious	Serious	Low	Low	Moderate	Low	Critical
Aldington [18]	2008	Low	Moderate	Low	Low	Low	Moderate	Moderate	Moderate
Berthiller [19]	2009	Low	Moderate	Low	Low	Low	Moderate	Moderate	Moderate
Bhattacharyya [20]	2015	Serious	Moderate	Low	Low	Low	Moderate	Moderate	Serious
Bonnet [21]	2013	Serious	Moderate	Low	NI	Moderate	Moderate	Low	Serious
Brumbach [22]	2019	Low	Moderate	Low	Low	Low	Low	Low	Moderate
Cook [24]	2014	Low	Moderate	Low	Low	Moderate	Moderate	Moderate	Moderate
Darling [25]	1993	Serious	Serious	Low	Low	Moderate	Moderate	Low	Serious
Darling [26]	2002	Serious	Serious	Low	Serious	Low	Moderate	Low	Serious
Darling [43]	1990	Critical	Serious	Serious	NI	Low	Moderate	Low	Critical
Donald [28]	1986	Critical	Serious	NI	NI	Low	NI	NI	Critical
Feng [29]	2019	Low	Moderate	Low	Low	Low	Low	Low	Moderate
Gillison [30]	2008	Low	Moderate	Low	Low	Low	Low	Low	Moderate
Han [31]	2010	Low	Moderate	Low	Low	Low	Moderate	Moderate	Moderate
Hashibe [32]	2006	Low	Low	Low	Low	Low	Low	Low	Moderate
Henderson [33]	1972	Critical	Critical	Serious	NI	NI	Serious	NI	Critical
Herning [34]	2008	Low	Moderate	Low	Low	Low	Low	Low	Moderate
Hess [35]	2014	Low	Moderate	Serious	Low	Low	Low	Low	Serious
Kagen [36]	1983	Critical	Serious	Low	Low	NI	Moderate	Low	Critical
Liang [37]	2009	Low	Moderate	Low	Low	Moderate	Low	Low	Moderate
Llewellyn [39]	2004	Low	Moderate	Low	Low	Low	Low	Low	Moderate
Llewellyn [40]	2004	Low	Moderate	Low	Low	Moderate	Moderate	Low	Moderate
Malhotra [41]	2017	Low	Moderate	Low	Low	Low	Moderate	Low	Moderate
Marks [42]	2013	Low	Moderate	Low	Low	Moderate	Low	Low	Moderate
Mueller [43]	1980	Serious	Serious	Low	Serious	Serious	Low	Low	Serious
Muller [45]	2015	Low	Moderate	Low	Low	Moderate	Low	Low	Moderate
Newman [46]	2019	Critical	Serious	Low	Serious	Low	Moderate	Low	Critical
Parshad [47]	1983	Serious	Serious	Low	NI	Low	Low	Low	Serious
Prasad [48]	2013	Serious	Low	Low	NI	Serious	Low	Low	Serious
Rosenblatt [49]	2004	Low	Moderate	Low	Low	Low	Low	Low	Moderate
Shah [50]	2018	Serious	Serious	Serious	Serious	Low	Low	Low	Serious
Spector [52]	1974	Critical	Serious	Low	Serious	Low	Low	Low	Critical
Stokes [53]	2000	Serious	Serious	Serious	Serious	Low	Serious	Low	Serious
Tashkin [54]	2012	Low	Moderate	Low	Low	Moderate	Moderate	Low	Moderate
Taylor [55]	1988	Critical	Critical	Critical	Serious	Moderate	Serious	Low	Critical
Tennant [56]	1971	Critical	Serious	Critical	Serious	Serious	Serious	Moderate	Critical
Weich [57]	2012	Serious	Serious	Moderate	Serious	Low	Serious	Low	Serious
Xie [59]	2018	Low	Moderate	Low	Low	Low	Low	Low	Moderate
Zhang [60]	1999	Low	Moderate	Low	Low	Low	Low	Low	Moderate
Zhang1 [11]	2000	Low	Moderate	Low	Low	Moderate	Low	Low	Moderate
Zhang [62]	2019	Low	Moderate	Low	Low	Low	Low	Low	Moderate
Zuskin [63]	1990	Serious	Serious	Serious	Serious	Low	Moderate	Low	Serious