Table 3.

Quality Assessment of Included Studies using the Newcastle–Ottawa Scale (each study is allotted the stars (*) for each category (Selection, Comparability and Outcome/Exposure).

Study	Selection	Comparability	Outcome/Exposure	Total
[35]	****	*	**	7
[36]	*****	*	***	9
[37]	****	*	**	7
[38]	**	*	***	6
[39]	***	*	*	5
[40]	***	*	***	7
[41]	**	*	**	5
[42]	*	*	**	4
[28]	*****	*	*	7
[43]	***	*	***	7
[44]	*****	*	**	8
[45]	*****	*	***	9
[46]	*****	*	**	8
[47]		*	**	3