Table 3.

Summary of risk of bias ratings assigned to the studies.

Domain	Eguchi et al. [39]	Gravel et al. [40]	Guo et al. [41]	Guo et al. [42]	Julander et al. [43]	Lv et al. [44]	Wang et al. [45]	Xu et al. [46]	Xu et al. [47]	Xu et al. [48]	Yu et al. [49]	Zheng et al. [50]	Zheng et al. [51]	Guo et al. [52]	Yu et al. [53]	Li et al. [54]	Wu et al. [55]	Xu et al. [56]	Xu et al. [57]
Study group representation
Knowledge of group assignments
Exposure assessment methods
Outcome assessment methods
Confounding
Incomplete outcome data
Selective outcome reporting
Financial conflict of interest
Other

Note: green—low risk of bias, blue—probably low risk of bias, amber—probably high risk of bias, and red—high risk of bias.