Table 4.

Risk of Bias (RoB). The * symbol mean that the study is fulfilling the criteria.

	Representativeness of Exposed Cohort	Selection of Non-Exposed Cohort	Ascertainment of Intervention	Demonstrate Outcome Assessed before Intervention	Comparability of Cohorts on the Basis of Design or Analysis	Assessment of Outcome	Follow-Up Long Enough	Adequacy of Follow-Up	Data available (No Missing Data)	Total
Janeczko et al. [13]	*	*	*	*		*			*	6
Song et al. [11]		*	*		*	*			*	5
Korpela et al. [9]			*	*		*	*	*	*	6
Marselle et al. [10]	*	*	*		*	*			*	6
Iwata et al. [21]			*	*		*				3
Gotink et al. [14]	*	*	*		*	*			*	6
Shin et al. [12]	*		*		*	*			*	5