Table 2. The main characteristics of the included studies regarding association between the GNB3 C825T polymorphism and stroke.

Author	Year	Country	Ethnicity	Sample sizeStroke/Control, n	Stroke/Control, n			Stroke/Control, n		HEWY/N	T frequency in control	SOCPB/HB	Score
					CC	CT	TT	C	T
Zhang [12]	2005	China	Asian	922/1124	212/244	512/569	198/311	936/1057	908/1191	Y	0.530	PB	8
Morrison [11]	2001	America	Caucasian	990/1124	266/311	512/569	212/244	1044/1191	936/1057	Y	0.470	PB	9
Zhao [34]	2001	China	Asian	294/280	89/93	144/133	61/54	322/319	266/241	Y	0.430	PB	7
Tan [35]	2003	China	Asian	100/100	32/65	58/32	10/3	122/162	78/38	Y	0.190	PB	7
Wang [36]	2011	China	Asian	80/110	26/34	46/70	8/6	98/138	62/82	N	0.373	PB	7
Zhao [38]	2000	China	Asian	715/668	196/195	348/338	171/135	740/728	690/608	Y	0.455	PB	8
Li [39]	2003	China	Asian	144/352	36/64	70/175	38/113	142/303	146/401	Y	0.570	PB	7
Zhao [37]	2004	China	Asian	182/190	35/55	87/92	60/43	157/202	207/178	Y	0.468	PB	7

HT, hypertension; SOC, source of control; PB, population-based, controls were blood donors, healthy controls matched for age, gender and domicile and participants in an health service programme from the same geographical region without clinically detectable hypertension; HB, hospital-based, controls were patients admitted to hospital without hypertension matched for age, gender and domicile; HWE, Hardy–Weinberg equilibrium; and MAF, minor allele frequency. Five studies [11], [12], [34]–[36] regarding the association of the GNB3 C825T polymorphism and ischemic stroke were identified while one [37] was regarding cerebral hemorrhage and the other two [38], [39] included ischemic stroke or cerebral hemorrhage cases.