Supplementary Table 3.

Bias assessment

Cohort studies
Quality assessment criteria	Acceptable (*)	Berzosa et al.	Sugimoto et al.	Hasan et al.
Selection
Representativeness	Population based
Cohort size	Drawn from the same community as exposed cohort	*	*	*
Clinical outcomes	Secured records, clinical outcomes	*	*	*
Demonstration that outcome of interest was not present at start of study?	Not present
Comparability
Factors comparable between groups?	Yes	*	*	*
Outcome
Assessment of outcome?	Independent blind assessment, record linkage	*	*	*
Follow-up time	Mentioned or not mentioned	*	*	*
Adequacy of follow-up of cohorts?	Complete follow-up, or subjects lost to follow-up unlikely to introduce bias	*	*	*
Overall quality score		6	6	6
Randomized control trials
Study quality	Attam et al.	Mok et al.	Wang et al.
Randomization present	*	*	*
Appropriate randomization utilized	*	*	*
Blinding present	*	*	*
Appropriate blinding method utilized	*	*	*
Appropriate long-term follow-up	*	*	*
Max score	5	5	5