Table.

Summary of risk of bias assessment of included studies

Newcastle-Ottawa scale (NOS) for cohort studies
	Study	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 of cohorts based on the design or analysis	Assessment of outcome	Was follow up long enough for outcomes to occur	Adequacy of follow up of cohorts	Overall RoB ‡ (NOS score)
1	DiPiro 199819	*	*		*		*	*		Poor (5)
2	Abidi 200820	*	*	*		*	*	*	*	Good (7)
3	Pestana 200941	*					*	*		Poor (3)
4	Smithson 200923	*	*	*		*	*	*		Good (6)
5	Smithson 200922	*	*			*		*		Poor (4)
6	Shaaban 201024	*	*	*		*	*	*	*	Good (7)
7	Laviolle 201225	*		*			*	*	*	Poor (5)
8	Merino 201226	*		*	*	*	*	*	*	Good (7)
9	Terradas 201228	*		*		*	*	*	*	Fair (6)
10	Gerrits 201327	*	*	*		*	*	*		Good (6)
11	Kotecha 201329	*	*	*		*	*	*		Good (6)
12	Kulaylat 201330	*	*	*	*		*	*		Poor (6)
13	Pitman 201331	*		*	*		*	*		Poor (5)
14	Yip 201332	*	*	*			*	*		Poor (5)
15	Garnaco-Montero 201433	*	*	*		*	*	*	*	Good (7)
16	Salturk 201536	*		*	*	*	*	*		Good (6)
17	Anand 201635	*	*	*		*	*	*	*	Good (7)
18	Lavoignet 201637	*	*	*		*	*	*		Good (6)
19	Roeker 201640	*	*	*		*	*	*	*	Good (7)
20	Aponte 201738	*	*					*		Poor (3)
21	Lavoignet 201939	*	*	*		*	*	*		Good (6)
22	Rosman 201947	*	*	*	*		*	*		Poor (6)
23	Von Meijenfeldt 201943	*	*	*	*	*	*	*		Good (7)
24	Varghese 201948	*	*	*		*	*			Poor (5)
25	El Fakhr 202045	*	*	*		*				Poor (4)
26	Joy 202046	*	*	*		*		*		poor (5)
27	Mahmoud 202044	*	*	*		*	*	*		Good (6)
28	Venet 200449	*	*	*	*	*	*	*	*	Good (8)
29	Allen 199050	*	*				*	*		Poor (4)
30	Nakos 199852	*	*	*	*	*	*	*	*	Good (8)
31	Jacobs 199951	*	*	*			*	*		Poor (5)
32	Hallgren 198453	*	*		*		*	*	*	Poor (6)
33	Modig 198614	*	*		*		*			Poor (4)
34	Hallgren 198715	*	*	*	*		*		*	Poor (6)
35	Willetts 201154	*	*	*	*		*		*	Poor (6)
36	Zhang 201955	*	*	*	*		*	*		Poor (6)

Newcastle-Ottawa scale (NOS) for case-control studies
	Study	Case definition	Representativeness of the cases	Selection of control	Definition of control	Comparability of case and control based on the design or analysis	Ascertainment of exposure	Method of ascertainment for cases and controls	Non-response rate	Overall RoB ‡ (no.)
1	Ho 200921	*	*	*	*	*	*	*		Good (7)
2	Escobar-Valdivia 201534	*	*	*	*	*	*	*		Good (7)
3	Widuri 202042	*	*				*			Poor (3)

‡ The risk of bias (RoB) is rated as: Good quality: 3 or 4 stars in selection domain AND 1 or 2 stars in comparability domain AND 2 or 3 stars in outcome/exposure domain, Fair quality: 2 stars in selection domain AND 1 or 2 stars in comparability domain AND 2 or 3 stars in outcome/exposure domain, Poor quality: 0 or 1 star in selection domain OR 0 stars in comparability domain OR 0 or 1 stars in outcome/exposure domain