Table 3.

Newcastle-Ottawa Quality Scale assessment for cohort studies. Stars (*) are assigned to each item if the requirement is satisfied.

Author(s) (Year)	Selection				Comparability		Outcome			Total Stars
	S1	S2	S3	S4	C1a	C1b	O1	O2	O3
Hillegers et al., (2004)		*	*	*	*	*	*		*	7
Duffy et al., (2007)	*	*	*	*		*	*	*	*	8
Goldstein et al., (2009)	*	*			*	*	*			5
Kemner et al., (2015)		*	*	*	*	*	*	*	*	8
Doucette et al., (2016)	*	*		*	*		*	*		6
Koenders et al., (2020)	*	*		*	*	*	*	*		7