Table 3.

Risk of bias assessment.

	1. Selection bias–Sequence generation	2. Selection bias–Baseline characteristics	3. Selection bias– Allocation concealment	4. Performance bias–Random housing	5. Performance bias–Blinding	6. Detection bias–Random outcome	7. Detection bias–Blinding	8. Attrition bias–Incomplete outcome data	9. Reporting bias–Selective outcome reporting	10. Other–Other sources of bias	Blinding mentioned	Randomization mentioned	Sample size calculation	Ethical approval mentioned	Conflict of interest statement mentioned
Cho et al. (2016)34	?	?	?	?	?	?	?	?	?	?	No	Yes	No	Yes	Yes
Ding et al. (2015)22	?	?	?	?	?	?	?	?	?	?	No	Yes	No	Yes	Yes
Ding et al. (2017)23	?	?	?	?	?	?	?	?	?	?	No	Yes	No	Yes	Yes
Larpthaveesarp et al. (2021)37	?	Low	?	?	?	?	Low	?	?	?	Yes	Yes	Yes	Yes	Yes
Kim et al. (2012)35	?	Low	?	?	?	?	?	?	?	High	Yes	Yes	No	Yes	No
Lee et al. (2010)36	?	?	?	?	?	?	Low	?	?	High	Yes	Yes	No	Yes	No
Li et al. (2014)24	?	?	?	?	?	?	?	?	?	?	No	Yes	No	No	Yes
Ohshima et al. (2015)40	?	?	?	?	?	?	?	?	?	High	Yes	Yes	No	Yes	No
Sakai et al. (2018)41	?	Low	?	?	?	?	?	?	?	?	No	Yes	No	Yes	Yes
van Velthoven et al. (2017)38	?	?	?	?	?	?	?	?	?	?	No	Yes	No	Yes	Yes
van Velthoven et al. (2013)33	?	?	?	?	?	?	?	?	?	?	No	No	No	Yes	Yes
van Velthoven et al. (2010)29	?	?	?	?	?	?	Low	?	?	?	Yes	Yes	No	Yes	No
van Velthoven et al. (2010)31	?	?	?	?	?	?	Low	?	?	High	Yes	No	No	Yes	No
van Velthoven et al. (2010)32	?	?	?	?	?	?	Low	?	?	High	Yes	No	No	Yes	No
van Velthoven et al. (2012)30	?	?	?	?	?	?	Low	?	?	?	Yes	Yes	No	Yes	Yes
Wei et al. (2015)39	?	?	?	?	?	?	?	?	?	?	Yes	Yes	Yes	Yes	Yes
Xia et al. (2010)25	?	?	?	?	?	?	?	?	?	?	Yes	Yes	No	Yes	Yes
Yang et al. (2020)28	Low	?	?	?	?	?	?	?	?	?	No	Yes	No	Yes	Yes
Zhang et al. (2014)26	?	?	?	?	?	?	?	?	?	High	No	Yes	No	Yes	No
Zhou et al. (2015)27	?	?	?	?	?	?	?	?	?	?	No	No	No	Yes	Yes

? = unclear risk of bias; Low = low risk of bias; High = high risk of bias.