Table 7.

Cochrane risk of bias assessment

1st Author (year)	Random sequence generation	Allocation concealment	Blinding of participants, personnel, and outcome assessors	Complete collection and reporting of outcome data	Selective outcome reporting	Other sources of bias
Chen (2010) [30]	Unclear	Unclear	High	Low	Low	Low
Davidson (2001) [18]	Low	Unclear	High	Low	Low	Low
Fink (2002) [15]	Low	Unclear	Low	Low	Low	Low
Grua (1999) [19]	Unclear	Unclear	High	Low	Low	Low
Irnich (2003) [17]	High	High	Low	Low	Low	High
Jin (2005) [33]	Unclear	Unclear	High	Low	Low	Low
Li (1998) [28]	Unclear	Unclear	High	Low	Low	Unclear
Li (2007) [22]	Unclear	Unclear	High	Low	Low	Low
Liu (2008) [23]	Unclear	Unclear	High	Low	Low	Unclear
Lin (2011) [21]	Unclear	Unclear	High	Low	Low	Low
Molsberger (1994) [16]	Unclear	Unclear	High	Low	Low	Low
Shen (1999) [20]	Unclear	Unclear	High	Low	Low	Unclear
Wang (2007) [24]	High	High	High	Low	Low	Low
Wang (2008) [25]	Unclear	Unclear	High	Low	Low	Low
Wu (2003) [26]	Unclear	Unclear	High	Low	Low	Low
Xu (2010) [29]	Unclear	Unclear	High	Low	Low	Unclear
Zha (2004) [31]	Low	Unclear	High	Low	Low	Low
Zhang (2007) [32]	Low	High	High	Low	Low	Low
Zhao (2003) [27]	High	High	High	Low	Low	Unclear