Table 2.

Study quality or risk of bias report.

Author	Year	Random allocation	Allocation concealment	Blinding of participants and personnel	Blinding of outcome assessment	Complete outcome data	Nonselective reporting	No other bias risk
Bang et al. [9]	2005	√	√	√	√	√	√	√
Sun et al. [10]	2008	√	Χ	Χ	Χ	Χ	Χ	Χ
Niu et al. [11]	2010	√	Χ	Χ	Χ	Χ	Χ	Χ
Bhasin et al. [12]	2011	Χ	Χ	Χ	√	√	√	√
Deng et al. [13]	2012	Χ	Χ	Χ	Χ	Χ	Χ	Χ
He [14]	2012	√	Χ	Χ	Χ	Χ	Χ	Χ
Bhasin et al. [15]	2012	Χ	Χ	Χ	√	√	√	√
Xiao [16]	2013	√	Χ	Χ	Χ	Χ	Χ	Χ
Bhasin et al. [17]	2013	Χ	Χ	Χ	√	√	√	√
Liu et al. [18]	2014	√	Χ	Χ	Χ	Χ	Χ	Χ
Xie et al. [19]	2014	√	Χ	Χ	Χ	Χ	Χ	Χ
Chen et al. [20]	2014	√	√	√	√	√	√	√
Prasad et al. [21]	2014	√	√	√	√	√	√	Χ
Zhang et al. [22]	2015	√	Χ	Χ	Χ	Χ	Χ	Χ
Shen [23]	2015	√	Χ	Χ	Χ	Χ	Χ	Χ
Cai et al. [24]	2015	√	√	Χ	Χ	Χ	Χ	Χ