Table S1.

Evaluations of the qualities of the included studies based on the Newcastle–Ottawa Scale

Author	Selection				Comparability	Outcome			Total
	1) Representativeness of the exposed cohort	2) Selection of the nonexposed cohort	3) Ascertainment of exposure	4) Demonstration that outcome of interest was not present at start of study	1) Comparability of cohorts on the basis of the design or analysis	1) Assessment of outcome	2) Was follow-up long enough for outcomes to occur	3) Adequacy of follow up of cohorts
Tsukao et al1	*	*	*		**	*	*	*	8
Liao et al2	*	*	*		*	*		*	6
Gokmen-Polar and Badve3	*	*	*		*	*		*	6
Santagata et al4	*	*	*		**	*	*	*	8
Chuma et al5	*	*	*		**	*	*	*	8
Zhang et al6	*	*	*		*	*	*	*	7
Fang et al7	*	*	*		*	*		*	6
Zhou et al8	*	*	*		*	*			5
Cui et al9	*	*	*		*	*	*	*	7
Liang et al10	*	*	*		*	*		*	6

Note: The “^*” denotes 1 point and “^**” denotes 2 points.