Table 8.

Assessment of cohort studies using the Newcastle–Ottawa scale

Study	Selection				Comparability	Outcome			∑
	Question				Question	Questions
	(1)	(2)	(3)	(4)	(1)	(1)	(2)	(3)
[60]		*	*	*	*	*	*		6
[64]		*	*	*	*		*		5
[54]		*	*	*	*				4
[57]		*	*	*	*	*	*		6
[59]			*	*	*	*	*		5
[61]		*	*	*	*	*	*		6
[62]		*	*	*	*	*	*		6
[67]		*	*	*	*	*	*	*	7