Table 3.

NOS scores of studies included in the meta-analysis

Author, year	Selection	Comparability	Outcome/exposure	Total score
Fotopoulou et al., 2008 [27]	****	**	**	8
Fotopoulou et al., 2009 [14]	****	**	**	8
Mereu et al., 2009 [28]	***	*	**	6
Guardiola et al., 2010 [29]	***	*	*	5
Saadeh et al., 2013 [30]	****	**	**	8
Pant et al., 2014 [31]	***	**	**	7
Chavan et al., 2017 [15]	****	**	**	8
Greco et al., 2017 [32]	****	**	**	8
Kuk et al., 2017 [33]	****	**	*	7
Zhang et al., 2018 [16]	****	**	**	8
Salinaro et al., 2020 [17]	****	**	*	7