Table 1.

Joanna Briggs Institute (JBI) scores for cross sectional studies

Study	JBI score	Participants and setting described in detail, including similarity of controls	Criteria for inclusion clearly defined and exposures similarly measured	Exposure measured in valid and reliable way	Objective, standard criteria used for measurement of condition	Confounding factors identified	Strategies to deal with confounding factors stated	Outcomes measured in valid and reliable way	Appropriate statistical analysis used?
Austria-Corrales 2011	7	+	+	-	+	+	+	+	+
Bai 2004	8	+	+	+	+	+	+	+	+
Bukhari 2016	7	+	+	+	+	+	-	+	+
Chan 2004	8	+	+	+	+	+	+	+	+
Chan 2005	7	+	+	+	+	+	-	+	+
Cheng-Sheng Chen 2005	7	+	+	+	+	+	-	+	+
Chua 2004	7	+	+	+	+	+	-	+	+
Fiksenbaum 2006	6	+	+	+	+	-	-	+	+
Goulia 2010	6	+	+	+	+	-	-	+	+
Grace 2005	5	+	+	+	-	-	-	+	+
Hawryluck 2004	8	+	+	+	+	+	+	+	+
Ho 2005	6	+	+	+	+	-	-	+	+
Huang 2020	6	+	+	+	+	-	-	+	+
Khalid 2016	4	+	+	+	+	-	-	-	-
Kim 2016	8	+	+	+	+	+	+	+	+
Koh 2005	7	+	+	+	+	+	-	+	+
Lai 2020	8	+	+	+	+	+	+	+	+
Lee 2005	4	+	+	+	+	-	-	-	-
Lehmann 2016	8	+	+	+	+	+	+	+	+
Li 2015	8	+	+	+	+	+	+	+	+
Lu 2006	6	+	+	+	+	-	-	+	+
Maunder 2004	8	+	+	+	+	+	+	+	+
Maunder 2006	7	+	+	+	+	+	-	+	+
Nickell 2004	6	+	+	+	+	-	-	+	+
Oh 2017	8	+	+	+	+	+	+	+	+
Park 2018	8	+	+	+	+	+	+	+	+
Phua 2005	8	+	+	+	+	+	+	+	+
Tam 2004	8	+	+	+	+	+	+	+	+
Tang 2017	8	+	+	+	+	+	+	+	+
Verma 2004	7	+	+	+	+	+	-	+	+
Wu 2009	8	+	+	+	+	+	+	+	+
Yu 2003	8	+	+	+	+	+	+	+	+
Xuehua 2003	7	+	+	+	+	+	-	+	+
Lin 2007	8	+	+	+	+	+	+	+	+
Marjanovic 2007	6	+	+	+	+	-	-	+	+
Matsuishi 2012	8	+	+	+	+	+	+	+	+
Poon 2005	7	+	+	+	+	+	-	+	+
Sim 2004	8	+	+	+	+	+	+	+	+
Sin 2004	6	+	+	+	+	-	-	+	+
Styra 2008	8	+	+	+	+	+	+	+	+
Wong 2005	6	+	+	+	+	-	-	+	+
Wong 2004	7	+	+	+	+	+	+	-	+
Xing 2020; preprint	8	+	+	+	+	+	+	+	+
Liu 2020; preprint	7	+	+	+	+	+	-	+	+
Huang 2020; preprint	7	+	+	+	+	+	-	+	+
Zhou 2020; preprint	7	+	+	+	+	+	-	+	+
Dai 2020; preprint	7	+	+	+	+	+	-	+	+