Table 3.

Risk of bias assessment using the Newcastle–Ottawa scale for cohort studies included in the systematic review and meta-analysis.

	Selection				Comparability	Exposure
Study	Representativeness of the exposed cohort (*)	Selection of the nonexposed cohort (*)	Ascertainment of exposure (*)	Demonstration that outcome of interest was not present at start of study (*)	Comparability of cohorts on the basis of the design or analysis (**)	Assessment of outcome (*)	Was follow-up long enough for outcomes to occur (*)	Adequacy of follow up of cohorts (*)
Liu 2021	*	*	*	*	*	*	*	*
Watanabe 2021	*	*	*	*	*	*	*	*
Rodkey 2021	*	*	*	*	*	*	*	*
Lin 2021	*	*	*	*	*	*	*	*
Jin 2021	*	*	*	*	*	*	*	*
Zhang 2020	*	*	*	*	*	*	*	*
Hou 2020	*	*	*	*		*	*	*
Chen 2020	*	*	*	*	*	*	*	*
Jacquet 2020	*	*	*	*	**	*	*	*
Song 2019	*	*	*	*	**	*	*	*
Koh 2019	*	*	*	*		*	*	*
Ryu 2018	*	*	*	*	*	*	*	*
Cho 2018	*	*	*	*		*	*	*
Maxwell 2017	*	*	*	*		*	*	*
Krych 2017	*	*	*	*		*	*	*
Jeon 2017	*	*	*	*	**	*	*	*
Petersen 2016	*	*	*	*		*	*	*
Tuncay 2015	*	*	*	*	*	*	*	*
Yim 2013	*	*	*	*	**	*	*	*
Takeuchi 2010	*	*	*	*	*	*	*	*
Weale 1994	*	*	*	*	**	*	*	*
Ivarsson 1991	*	*	*	*	*	*		*
Broughton 1986	*	*	*	*	*	*	*	*