Table 1.

Main characteristics of studies included in the meta-analysis.

Study/year	Country	Genotypingmethod	Case	Control	Case					Control					HWE
					GG	GA	AA	G	A	GG	GA	AA	G	A
Aftabi et al. 2017	Iran	PCR-RFLP	135	130	68	62	5	198	72	73	53	4	199	61	0.120
Gu et al. 2011	China	TaqMan	567	573	255	231	81	741	393	249	244	80	742	404	0.108
Liu et al. 2016	China	PCR	136	456	58	57	18	173	93	193	206	55	592	316	0.998
Merisalu et al. 2007	Estonia	ASPCR	110	211	96	14	0	206	14	175	36	0	386	36	0.195
Mostafa et al. 2017	Egypt	Real-time PCR	120	50	43	21	56	107	133	28	15	7	71	29	0.055
Safarinejad et al. 2013	Iran	PCR	176	352	73	89	14	235	117	131	152	69	414	290	0.710
Watanabe et al. 2004	Japan	PCR	123	112	36	64	23	136	110	32	58	22	122	102	0.641