Supplementary Table 1.

Risk of Bias assessment of the observational studies.

Study name, year	Fan e al 201726	Kamishima 201928	Kario et al 201429	Lee et al 201730	Lee et al 201831	Ogihara et al 200932,33	Teramoto 201235	Wan et al 201836	Yamashita 201338	Yamazaki et al 201339	Zheng et al 201540
Representativeness of the exposed cohort	*	*	*	*	*	-	*	*	*	*	*
Selection of the non-exposed cohort	*	*	*	*	*	*	*	*	*	*	*
Ascertainment of exposure	*	*	*	-	-	*	-	-	-	-	*
Demonstration that outcome of interest was not present at start of study	*	*	*	*	*	*	*	*	*	*	*
Comparability	*	*	*	*	*	-	*	*	*	*	*
Assessment of outcome	*	-	*	*	*	*	-	*	*	-	*
Long enough follow-upa	*	*	*	*	*	*	*	*	*	*	*
Adequacy of follow-up of cohorts	-	-	-	*	*	-	*	*	-	-	-
General assessment of bias risk	Unclear	High	Unclear	Unclear	Unclear	High	High	Unclear	High	High	Unclear

Notes:

^*- low risk of bias;

^“-”- unclear or high risk of bias.

^aIf 1 year or more.