Table 1. Characteristics of included studies in this meta-analysis.

No	First Author	Year	Population	Typing method	Diagnostic criteria	Patients	Controls	Molecular or serological study
1	Qin19	2015	Chinese	PCR-SSP	ND	100	100	Molecular
2	Papadopoulou15	2012	Swedish	PCR-SSP	WHO criteria, 1999	452	168	Molecular
3	Papadopoulou21	2009	Swedish	PCR-SSP	OGTT*	764	1191	Molecular
4	Wang27	2008	Chinese	PCR-SSP	OGTT**	39	42	Molecular
5	Zhou28	2007	Chinese	PCR-SSP	OGTT**	26	42	Molecular
6	Liu16	2006	Chinese	PCR-SSP	OGTT**	50	50	Molecular
7	Li29	2005	Chinese	PCR-SSP	OGTT**	116	73	Molecular
8	Zhao18	2005	Chinese	PCR-SSP	WHO criteria, 1998	48	48	Molecular
9	Shaat22	2004	Scandinavian and Arabian	Hybridisation	OGTT*	500	550	Molecular
10	Song23	2002	Chinese	PCR-SSP	NDDG criteria	30	40	Molecular
11	Weng11	2002	Swedish	Dot-blotting	OGTT*	65	86	Molecular
12	Ferber24	1999	German	PCR-SSO	GDA criteria	184	254	Molecular
13	Vambergue25	1997	French	AFLP	Carpenter and Coustan’s criteria	95	95	Molecular
14	Acton13	1997	African-American	Microdroplet cytoxicity procedure and/or PCR-SSP	NDDG criteria	465	232	Molecular
15	Lapolla17	1996	Italian	Microlymphocytotoxicity method	Carpenter and Coustan’s criteria	52	51	Serological
16	Rubinstein26	1981	Puerto Rican and American	TCF	ND	136	417	Serological

PCR polymerase chain reaction, SSP sequence-specific primers, SSO sequence-specific oligonucleotide, AFLP Amplification Length Fragment Polymorphism, TCF two-color fluorescence, OGTT* based on 75-g OGTT and defined as a 2-h capillary glucose concentration (CGC) of at least 9 mmol/L, OGTT** based on 75-g OGTT and met at least two following conditions (0-h CGC ≥ 5.6 mmol/L; 1-h CGC ≥ 10.3 mmol/L; 2-h CGC ≥ 8.6 mmol/L; 3-h CGC ≥ 6.7 mmol/L), NDDG The national diabetes Data Group, GDA German Diabetes Association, ND not available data.