Table 2 Quality assessment of the cross-sectional studies included in systematic review and meta-analysis※
Studies | Type of study | A | B | C | D | Total score |
|---|---|---|---|---|---|---|
Zhang 2006 [14] | CS | 1 | 1 | 1 | 1 | 4 |
Xi 2011 [20] | CS | 1 | 1 | 0 | 1 | 3 |
He 2009 [21] | CS | 1 | 1 | 0 | 1 | 3 |
Huan 2007 [22] | CS | 1 | 1 | 0 | 1 | 3 |
Wu 2008 [23] | CS | 1 | 1 | 0 | 1 | 3 |
Wang 2007 [34] | CS | 1 | 1 | 1 | 1 | 4 |
Bai 2004 [35] | CS | 1 | 1 | 1 | 1 | 4 |
Liao 2009 [36] | CS | 1 | 1 | 0 | 1 | 3 |
Yang 2010 [37] | CS | 1 | 1 | 0 | 1 | 3 |
Zhou 2009 [38] | CS | 1 | 1 | 0 | 1 | 3 |
Li 2002 [39] | CS | 1 | 1 | 0 | 1 | 3 |
Shi 2006 [40] | CS | 1 | 1 | 0 | 1 | 3 |
Yu 2007 [41] | CS | 1 | 1 | 0 | 1 | 3 |
Zhang 2011 [42] | CS | 1 | 1 | 0 | 1 | 3 |
Cai 2007 [43] | CS | 1 | 1 | 0 | 1 | 3 |
Chai 2008 [44] | CS | 1 | 1 | 0 | 1 | 3 |
Tian 2001 [45] | CS | 1 | 1 | 0 | 1 | 3 |
Yang 2011 [46] | CS | 1 | 1 | 1 | 1 | 4 |
Cao 2002 [47] | CS | 1 | 1 | 0 | 1 | 3 |
Geng 2010 [48] | CS | 1 | 1 | 1 | 1 | 4 |
Shi 2008 [49] | CS | 1 | 1 | 1 | 1 | 4 |
Cheng 2005 [50] | CS | 1 | 1 | 1 | 1 | 4 |
Li 2012 [51] | CS | 1 | 1 | 1 | 1 | 4 |
Hou 2001 [54] | CS | 1 | 1 | 0 | 1 | 3 |
Liu 2000 [55] | CS | 1 | 1 | 0 | 1 | 3 |
Li 2010 [56] | CS | 1 | 1 | 0 | 1 | 3 |
Lian 2003 [57] | CS | 1 | 1 | 0 | 1 | 3 |