Table 2.

Study quality evaluation via the Newcastle-Ottawa Scale.

Study	Representativeness of the exposed cohort	Selection of the non-exposed cohort	Ascertainment of exposure	Outcome not present at baseline	Control for age and sex	Control for other confounding factors	Assessment of outcome	Enough long follow-up duration	Adequacy of follow-up of cohorts	Total
Lee 2012	0	1	1	1	1	1	1	1	1	8
Nielsen 2012	0	1	1	1	1	1	1	1	1	8
Choi 2013	0	1	1	1	1	0	1	1	1	7
Krane 2014	0	1	1	1	1	1	1	1	1	8
Hamilton 2014	0	1	1	1	1	1	1	1	1	8
Viers 2015	0	1	1	1	1	1	1	1	1	8
Kaffenberger 2015	0	1	1	1	1	1	1	1	1	8
Haddad 2015	0	1	1	1	1	1	1	1	1	8
McKay 2016	0	1	1	1	1	1	1	1	1	8
Nayan 2016	0	1	1	1	1	1	1	1	1	8
El-Refai 2017	0	1	1	1	1	0	1	0	1	6
Berquist 2017	0	1	1	1	1	1	1	1	1	8
Neumann 2019	0	1	1	1	1	1	1	1	1	8
Boegemann 2020	1	1	1	1	1	1	1	1	1	9
Heide 2020	0	1	1	1	1	1	1	1	1	8
Fiala 2021	1	1	1	1	1	1	1	1	1	9
Santoni 2022	0	1	1	1	1	1	1	1	1	8