Table 1.

Risk of bias assessment results of included studies

Study	Newcastle-Ottawa quality assessment scale
Selection	Comparability	Exposure
Is the case definition adequate? (Maximum: *)	Representativeness of the cases (Maximum: *)	Selection of Controls (Maximum: *)	Definition of Controls (Maximum: *)	Comparability of cases and controls based on the design or analysis (Maximum: * *)	Ascertainment of exposure (Maximum: *)	Same method of ascertainment for cases and controls (Maximum: *)	Non-Response rate (Maximum: *)	Total score (out of 9)
Costa 2022	*	*	*	*	**	*	*	*	*********(9)
Costa 2014	*	*	*	*	**	*	*	*	*********(9)
König 2001	*	*	*	*	**	*	*	*	*********(9)
Kocher 2024	*	–	*	*	**	*	*	*	********(8)
Miyamoto 2006	*	*	*	*	**	*	*	*	*********(9)
Rieder 2004	–	–	*	*	–	*	*	*	*****(5)
Roccuzzo 2022	*	*	*	*	**	*	*	*	*********(9)