Supplementary Table 1.

Quality assessment using Newcastle-Ottawa Scale for Cross-sectional studies*

Study	Selection				Comparability Comparability of Outcome groups on the Basis of design or analysis	Outcome		Study score
	Representativeness of The exposed sample	Sample size	Ascertainment of exposure	Selection of the non-exposed sample		Assessment of outcome	Suitability of statistical test
Ghorabi et al., 2019	*	-	*	*	**	*	*	7/7
Joyce et al., 2019	*	*	*	*	**	*	*	7/7
kang et al., 2018	*	*	*	*	**	*	*	7/7
Drehmer et al., 2017	*	*	*	*	**	*	*	7/7
Park et al., 2016	*	*	*	*	**	*	*	7/7
Saneei et al., 2015	-	-	*	*	**	*	*	6/7

*We used a modified NOS scale for cross sectional studies. Note: A score of 7 was considered as good quality