TABLE 2.

Quality assessment of included studies.

A. Case reports and case series
First author (year)	Selection	Ascertainment	Causality	Reporting	Risk of bias
Max score	1	2	2	1	6
Atsuumi et al. (9)	1	2	2	1	6
Eguchi et al. (11)	0	2	2	1	5
Iskos et al. (12)	0	2	2	1	5
Marrison and Parry (15)	0	1	1	1	3
Overdijk et al. (16)	0	1	1	1	3
Rytlewski et al. (17)	0	2	2	1	5
Shahab et al. (18)	0	1	1	1	3
Xu et al. (20)	0	2	2	1	5
B. Cohort studies and case-control studies
First author (year)	Selection	Comparability		Exposure/outcome	Risk of bias
Max score	4	2		3	9
Busweiler et al. (10)	4	2		2	8
Jardine et al. (6)	4	2		2	8
Kapoor (13)	2	0		3	5
Khadilkar et al. (14)	3	1		1	5
Tewfik et al. (19)	4	1		2	7