Table 3.

Newcastle-Ottawa for cross-sectional studies.

Cross sectional	Pitiphat et al. (31)	Sönmez et al. (32)	Souza et al. (33)	Allazzam et al. (35)	de Lima et al. (37)	Wollet et al. (40)
Selection (5 stars max)
1) Is the case definition adequate?	*	*	*	*	*	*
2) Sample	-	*	-	-	*	*
3) Non-respondents	*	*	*	-	*	*
4) Ascertainment of the exposure (risk factor)	**	**	**	**	**	**
Comparability (2 stars max)
1) The subjects in different outcome groups are comparable, based on the study design or analysis. confounding factors are controlled	*	**	*	*	**	*
Outcome (3 stars max)
1) Ascertainment of outcome	**	**	-	-	-	**
2) Statistical test	*	*	*	*	*	*

The * and ** symbols indicate score that each article received in the quality assessment.