Table 3.

Newcastle–Ottawa Scale for human cross-sectional studies.

Citation	Selection				Comparability	Outcome		Total	Rate
	Representativeness of the Sample	Sample Size	Non-Respondents	Ascertainment of the Exposure	The Subjects in Different Outcome Groups Are Comparable, Based on the Study Design or Analysis. Confounding Factors Are Controlled	Assessment of Outcome	Statistical Test
[33]	1	1	0	1	2	2	1	8	Good
[34]	1	1	0	1	2	2	1	8	Good
[35]	1	0	1	2	2	1	1	8	Good
[36]	1	0	1	2	1	1	1	7	Good
[37]	1	0	1	2	2	2	1	9	Good
[38]	1	1	0	1	2	2	1	8	Good
[13]	0	0	0	0	0	0	1	1	Poor
[39]	1	1	0	1	2	2	1	8	Good
[40]	1	0	1	2	1	1	1	7	Good
[41]	1	0	1	2	0	2	1	7	Good