Table 1.

Characteristics of studies included in the meta-analysis.

Authors	year	Source of controls	Area	Ethnicity	Genotype	C677T						A1298C
						Cases			Controls			Cases			Controls
						CC	CT	TT	CC	CT	TT	AA	AC	CC	AA	AC	CC
Jeng et al.	2003	PB	Taiwan	Mixed**	C677T	36	22	1	123	95	14
Zhang et al.	2005	PB	Beijing	Not stated	C677T, A1298C	120	230	155	160	231	109	355	141	9	345	150	5
Shen et al.	2005	PB	Yunnan	Not stated	C677T, A1298C	33	65	18	53	42	16	71	41	2	69	34	6
Jin et al. *	2007	PB	Guangzhou	Not stated	C677T, A1298C							70	28	2	68	30	2
Liu et al.	2008	HB	Nanjing	Han	C677T, A1298C	157	245	98	149	265	103	341	141	18	364	142	11
Liu et al.	2009	PB	Taiwan	Not stated	C677T, A1298C	205	124	29	362	291	63	228	115	15	467	226	23
Yao et al.	2010	PB	Hubei	Not stated	C677T	27	46	20	36	51	19
Yang et al.	2010	PB	Jiangxi	Han	C677T	49	52	19	62	75	28
Cui et al.	2011	PB	Shandong	Not stated	C677T	58	240	140	121	325	195
Cheng et al.	2011	PB	Henan	Han	C677T	49	58	71	47	88	45
Ma et al.	2012	HB	Yunnan	Han	C677T	20	54	46	22	28	10

PB – population-based; HB – hospital-based.

^*Study excluded from the meta-analysis of MTHFR C677T; not in Hardy-Weinberg equilibrium;

^**Including Fukien Taiwanese, Hakka Taiwanese and Mainland Chinese.