Table 1.

Quality of studies.

Risk of Bias	Selection of Participants	Confounding Variables	Intervention Measurement	Blinding of Outcome Assessment	Incomplete Outcome Data	Selective Outcome Reporting
Jin et al. [23], 2010	●	△	●	●	※	●
Lu [24], 2013	●	△	△	●	●	●
Feng et al. [25], 2013	●	△	●	●	●	●
Hu [26], 2015	△	●	※	●	△	△
Yuan [27], 2018	●	△	※	●	※	●
Liu & Zhong [28], 2018	●	△	※	●	●	△
Xu et al. [29], 2019	●	●	△	●	●	●
Fengyue&Junko [30], 2018	●	※	※	●	※	●
Yu et al. [31], 2015	●	△	※	●	△	※
Fan et al. [32], 2016	●	△	※	●	●	●
Qun [33], 2013	△	△	●	●	●	●
Li et al. [34], 2018	●	△	※	●	※	●
Jin, Li, et al. [35], 2018	※	△	●	●	※	※
Yang et al. [36], 2016	●	△	●	●	●	●
Lu et al. [37], 2017	●	●	※	●	●	●
Huang et al. [38], 2012	●	△	※	●	△	●
Song et al. [39], 2016	●	△	●	●	●	●
Fen et al. [40], 2017	●	△	※	●	●	※
Ryan Greysen [41], 2017	●	△	※	●	●	△
Lagergren et al. [42], 2018	●	●	※	●	※	●
Sharada et al. [43], 2018	●	△	●	●	△	●
Larissa S et al. [44], 2012	●	△	●	●	※	●
Mitsuhiro S et al. [45], 2018	●	●	※	●	●	●
Hajime T et al. [46], 2019	※	△	△	●	※	△
Greg A et al. [47], 2015	●	※	※	●	●	●
Ramon L et al. [48], 2018	●	●	※	●	●	●
Julieta et al. [49], 2016	●	△	※	●	●	●
Saori et al. [50], 2017	●	※	●	●	●	●
Edward et al. [51], 2016	●	△	●	●	●	※
Vicky et al. [52], 2017	※	△	△	●	△	●
Julie [53], 2019	●	△	●	●	※	●
Shota Hamada et al. [54], 2019	●	△	※	●	●	●
Peter et al. [55], 2015	●	●	※	●	△	△
Maria et al. [56], 2017	△	△	△	●	●	△
Leena et al. [57], 2017	●	△	●	●	※	●

Notes: ● Low risk of bias; △ High risk of bias; ※ Unclear.