Table 1.

Characteristics of the studies rs2234693 polymorphism included in the meta-analysis.

First author and publication year	Region	Gender (M/F)		Mean age (year)		Sample size		Genotype frequency in cases			Alleles, n in cases		Genotype frequency in controls			Alleles, n in control		P HWE
		Cases	Controls	Cases	Controls	Cases	Controls	TT	TC	CC	T	C	TT	TC	CC	T	C
Zheng, 2001 29	Guangdong	70/ 14	48/ 13	61.82±10.61	59.92±9.43	84	61	14	48	22	76	92	25	27	9	77	45	0.7
Guo, 2002 30	Guangdong	58/ 14	41/ 12	65.1±5.6	64.3+4.2	72	53	10	42	20	62	82	23	23	7	69	37	0.74
Huang, 2002 31	Hubei	81/ 54	50/ 68	No mentioned	No mentioned	135	118	80	41	14	201	69	51	54	13	156	80	0.82
Zheng, 2002 32	Hebei	0/ 51	0/ 54	64.21±9.75	62.05±7.8	51	54	9	35	7	53	49	18	30	6	66	42	0.21
Cheng, 2006 33	Tianjin	105/95	98/ 92	56.5±0.4	52.4±0.6	200	190	65	92	43	222	178	67	85	38	219	161	0.25
Li, 2006 34	Tianjin	0/ 165	0/80	61.7±8.2	59.9±7.7	165	80	33	88	44	154	176	21	36	23	78	82	0.37
Xu, 2008 19	Jiang- su	94/ 116	89/ 85	56.0±7.3	55.0±8.6	210	174	92	88	30	272	148	82	78	14	242	106	0.44
Tang, 2008 35	Hubei	161/0	158/0	61.4±8.1	60.9±6.4	161	158	48	76	37	172	150	46	79	33	171	145	0.93
Jin, 2010 36	Guangdong	169/67	75/ 42	64.0±11.0	62.0±11.0	236	117	84	105	47	199	273	49	57	11	79	155	0.33
Shen, 2012 37	Chongqing	289/250	286/253	57.3±7.2	56.4±9.1	539	539	245	226	68	716	362	274	217	48	765	313	0.59
Total						1853	1544	680	841	332	2127	1579	656	686	202	1922	1166

M: male; F: female; HWE: Hardy-Weinberg equilibrium.