Table 5.

Newcastle–Ottawa assessment scale for case–control studies

Study	Selection				Compatibility		Exposure			Total
	Definition of cases	Representativeness of cases	Selection of controls	Definition of controls	On age	On other risk factors	Assessment of exposure	Same methods of ascertainment for cases and controls	Non response rate
Goodman 2008 [18]	*	*	*	*	*	*	*	*	*	9
Goodman 2010 [34]	*	*	*	*	*	*	*	*	-	8
Slattery 2012 [30]	*	*	*	*	*	*	*	*	*	9
Dash 2013 [26]	*	*	*	*	*	*	*	*	*	9
Slattery 2014 [31]	*	*	*	*	*	*	*	*	-	8
Kong 2014 [28]	*	*	*	*	*	*	*	*	*	9
Sohouli 2022 [25]	*	*	*	*	*	*	*	*	*	9
Kim 2022 [33]	*	*	*	*	*	*	*	*	*	9
Bentyaghoob 2023 [32]	*	*	*	*	*	*	*	*	*	9