Quality assessment of included studies.

Supplementary Table 1: Quality assessment of included studies.

Criteria judged	Wu, et al. 2020 [19]	Guan, et al. 2020 [8]	Pung, et al, 2020 [17]	Yang, et al. 2020 [20]	Zhou, et al. 2020 [22]	Chen, et al. 2020 [12]	Huang, et al. 2020 [14]	Shi, Han, Jiang, et al. 2020 [18]	Zhang, et al. (2020) [21]	Hu, et al. (2020) [15]	Li, et al. (2020) [24]
Research question or objective clearly stated	√	√	√	√	√	√	√	√	√	√	√
Study population clearly specified and defined, including case definition	√	√	√	√	√	√	√	√	√	√	√
Inclusion and exclusion criteria applied uniformly to all participants	√	√	√	√	√	√	√	√	√	√	√
Provided sample size justification, power description, or variance and effect estimates	NR	NR	NR	√	NR	NR	NR	NR	NR	NR	NR
Intervention clearly described	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
Statistical methods well-described	√	√	ⅹ	√	√	√	√	√	√	√	√
Exposure of interest measured prior to the outcome being measured	NA	NA	NA	NA	√	NA	NA	NA	NA	NA	NA
Results well-described	√	√	√	√	√	√	√	√	√	√	√
Time frame sufficient to see an association between exposure and outcome	NA	NA	NA	NA	√	NA	NA	NA	NA	NA	NA
Outcome measures clearly defined, valid, reliable, and implemented consistently across all study participants	√	√	√	√	√	√	√	√	√	√	√
Key potential confounding variables measured and adjusted statistically	NR	NR	NR	NR	√	NR	√	√	√	NR	√

Note: √ = Yes; X = No; NR = Not reported; NA = Not applicable