Table 2.

Quality assessment results according to Downs and Black 27-item checklist

Study	Waitayawinyu et al. [14]	Lee et al. [15]	Wu et al. [16]	Hsiung et al. [17]	Wang et al. [18]	Wong et al. [19]
Result	Good (21)	Poor (14)	Fair (18)	Good (20)	Fair (17)	Poor (12)

Study	Liu et al. [20]	Lee et al. [21]	Oh et al. [22]	Cognet et al. [23]	Kang et al. [24]	Kimet al. [25]
Result	Fair (16)	Fair (16)	Good (22)	Poor (10)	Fair (17)	Fair (18)