Table 4.

Overall quality appraisal of included studies

Reference	Clearly defined inclusion criteria	Study participants and setting described in detail	Exposure measured in a valid and reliable way	Objective standard measurements of the condition	Confounding factors identified	Strategies to deal with confounding factors stated	Outcomes measured in a valid and reliable way	Appropriate statistical analysis used	Overall quality appraisal
Adriano-Anaya et al 201418	?	✓	✓	✓	✓	✓	✓	✓	Unclear
Aguilera-Galaviz et al 201919	✓	✓	✓	✓	✓	×	✓	?	Low
Ashi et al 201920	✓	×	✓	✓	×	×	✓	✓	Low
Caudillo-Joya et al 201421	?	✓	✓	✓	✓	✓	✓	✓	Unclear
De la Cruz Cardoso et al 201522	✓	?	✓	?	×	×	✓	?	Low
Garcia-Perez et al 202023	✓	✓	✓	✓	✓	✓	✓	✓	High
Irigoyen-Camacho et al 201324	✓	✓	✓	✓	✓	✓	✓	✓	High
Juarez-Lopez et al 201025	✓	✓	✓	✓	✓	✓	✓	✓	High
Lara-Capi et al 201826	✓	✓	✓	✓	✓	✓	✓	✓	High
Loyola-Rodriguez et al 201127	✓	✓	✓	✓	✓	✓	✓	✓	High
Patiño-Marín et al 201828	✓	✓	✓	✓	✓	✓	✓	✓	High
Ramirez-De los Santos et al 202029	✓	✓	✓	✓	✓	✓	✓	✓	High
Sanchez-Perez et al 201030	✓	✓	✓	✓	✓	✓	✓	✓	High
Serrano-Piña et al 202031	✓	✓	✓	?	✓	✓	✓	✓	Unclear
Silva-Flores et al 201332	✓	✓	?	?	✓	✓	✓	✓	Unclear
Vázquez-Nava et al 201033	✓	✓	✓	✓	✓	✓	✓	✓	High
Zelocuatecatl-Aguilar et al 200534	✓	✓	✓	✓	✓	✓	✓	✓	High
Zúñiga-Manríquez et al 201335	✓	✓	?	✓	×	?	✓	✓	Low

Symbols: ✓, yes; ×, no;?, unclear.