Table 3.

Quality assessment of included studies.

Cohort Studies/Cross-Sectional Studies
Author, Year	Selection				Comparability		Outcome
	Representative of Exposed Cohort	Selection of Non-Exposed Cohort	Ascertainment of Exposure	Demonstration That Outcome of Interest Was Not Present at Start of Study	Control For Important Factors	Additional Factors	Assessment of Outcome	Follow-Up	Adequacy of Follow-Up	Score
Gould et al., 2015 [19]	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	9
Accortt et al., 2016 [20]	No	Yes	Yes	No	Yes	Yes	Yes	Yes	No	6
Fu et al., 2014 [22]	Yes	Yes	Yes	No	Yes	Yes	Yes	Yes	Yes	8
Gur et al., 2013 [23]	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	Yes	8
Murphy et al., 2010 [24]	No	No	Yes	No	Yes	Yes	Yes	No	No	4
Robinson et al., 2014 [25]	Yes	Yes	Yes	No	Yes	Yes	No, modified	No	Yes	6
Williams et al., 2016 [26]	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	Yes	8
Huang et al., 2014 [27]	Yes	Yes	Yes	No	Yes	Yes	Yes	No	No	6
Brandenbarg et al., 2012 [28]	Yes	Yes	Yes	No	Yes	Yes	Yes	No	Yes	7
Cassidy-Bushrow et al., 2012 [29]	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	9
Miyake et al., 2015 [30]	Yes	Yes	Yes	No	Yes	Yes	Yes	No	No	6
Arnold et al., 2013 [31]	Yes	Yes	Yes	No	Yes	Yes	No	No	No	5
Case Controls
Selection					Comparability of Cases and Controls on Basis of Design of Analysis		Outcome
Author, Year	Adequate Case Definition	Representative of Cases	Selection of Controls	Definition of Controls			Ascertainment of Exposure	Same Method of Ascertainment for Cases and Controls	Non-Response Rate	Score
Nielsen et al., 2013 [21]	Yes	Yes	Yes	Yes	Yes		Yes	Yes	Yes	8