Table 1.

The characteristics of included studies

Authors	Publication year	Ethnicity	N	Stages	Quality Scores	Arg39-9G1n	Arg19-4Trp	Genotyping methods
Dong et al.	2012	Chinese	564	III-IV	5	Yes	No	PCR-RFLP
Joerger et al.,	2012	Caucasian	131	IIIB-IV	7	Yes	Yes	PCR-RFLP
Sullivan et al.	2014	Caucasian	161	III-IV	7	Yes	Yes	TaqMan
Zhao et al.	2013	Chinese	147	IIIB-IV	7	Yes	Yes	TaqMan
Jin ZY et al.	2014	Chinese	378	IIIB-IV	6	Yes	Yes	PCR-RFLP
Liu D et al.	2014	Chinese	378	IIIB-IV	6	Yes	Yes	SpectroCHIP microarray
Zhang et al.	2014	Chinese	375	IIIB-IV	6	Yes	Yes	PCR-RFLP
Liao et al.	2012	Chinese	62	IIIB-IV	5	Yes	No	PCR-RFLP
Xu CA et al.	2011	Chinese	130	IIIB-IV	4	Yes	Yes	PCR-RFLP
Zhao W et al.	2011	Chinese	151	IIIB-IV	6	Yes	Yes	PCR-RFLP
Cheng HY et al.	2011	Chinese	120	IIIB-IV	5	Yes	No	PCR
Zhou et al.	2011	Chinese	111	IIIB-IV	7	Yes	No	PCR
Han Y et al.	2011	Chinese	91	IIIB-IV	4	Yes	No	PCR-RFLP
Li DR et al.	2011	Chinese	89	IIIB-IV	6	Yes	No	PCR
Ding CL et al.	2010	Chinese	54	IIIB-IV	4	Yes	Yes	PCR
Qian XP et al.	2010	Chinese	107	IIIB-IV	5	Yes	No	PCR-RFLP
Ying RB et al.	2010	Chinese	80	IIIB-IV	4	No	Yes	PCR-RFLP
Sun XC et al.	2009	Chinese	82	IIIB-IV	7	Yes	Yes	PCR
Hong CY et al.	2009	Chinese	164	III-IV	6	Yes	Yes	PCR-RFLP
Qiu LX et al.	2009	Chinese	107	IIIB-IV	5	No	Yes	PCR-RFLP
Song DG et al.	2007	Chinese	97	IIIB-IV	6	Yes	Yes	PCR-RFLP
Gao CM et al.	2006	Chinese	57	IIIB-IV	5	Yes	Yes	PCR-RFLP
Jin YW et al.	2006	Chinese	162	IIIB-IV	6	No	Yes	PCR-RFLP
Yuan P et al.	2006	Chinese	200	IIIB-IV	6	No	Yes	PCR-RFLP
Wang ZH et al.	2004	Chinese	105	IIIB-IV	6	Yes	No
Kalikaki A et al.	2009	Caucasian	119	III- IV	6	Yes	No	PCR-RFLP
Giachino et al.	2007	Caucasian	248	IIIA- IV	7	Yes	Yes	PCR-RFLP
de las Penas et al.	2006	Caucasian	135	IIIB-IV	6	Yes	Yes	PCR-RFLP
Gurubhagavatula et al.	2004	Caucasian	103	IIIB-IV	7	Yes	Yes	PCR-RFLP