Table 3.

Risk of bias in Cross sectional studies.

Studies	Were the criteria for inclusion in the sample clearly defined?	Were the study subjects and the setting described in detail?	Was the exposure measured in a valid and reliable way?	Were objective, standard criteria used for measurement of the condition?	Were confounding factors identified?	Were strategies to deal with confounding factors stated?	Were the outcomes measured in a valid and reliable way?	Was appropriate statistical analysis used?
Mercante et al. (24)	Yes	Yes	Yes	Yes	Unclear	Unclear	Yes	Yes
Lampl et al. (25)	Yes	Yes	Yes	Yes	Yes	Unclear	Yes	Yes
Peres et al. (26)	Yes	Yes	Yes	Yes	Unclear	Unclear	Yes	Yes
Song et al. (27)	Yes	Yes	Yes	Yes	Unclear	Unclear	Yes	Yes
Wachholtz et al. (28)	Yes	Yes	Yes	Yes	Unclear	Unclear	Yes	Yes