|
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
|
- CC refers to case-control study; CS refers to cross-sectional study. ※ A. representativeness of study participants, B. proper methods to ascertain exposure, C. comparability of comparing analysis groups and D. lower non-response bias.
