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

Reference	Year	Ethnicity	Ethnic groups	Polymorphism	Case	Match criteria for control	No. of cases/controls	Source of control	Genotyping method
Zee [12]	2007	American	Caucasian	rs10757274	CT or MRI confirmed	Age, ethnicity, smoking status	254/254	Population	NA
Matarin [13]	2008	American	Caucasian	rs2383207	IS per WHO criteria	Age, sex, ethnicity	249/268	Population	Chip
Helgadottir [14]	2008	European	Caucasian	rs10757278	CT or MRI confirmed	Ethnicity	705/14993	Population	Chip
Smith [15]	2009	Swedish	Caucasian	rs2383207	IS per WHO criteria	Age, sex, ethnicity, time of baseline investigation	2725/1840	Population	MassArray
Gschwendtner [22]	2009	European, African American	Caucasian, African American	rs10757278	CT or MRI confirmed	Age, sex, ethnicity, site of enrolment	932/4150	Population	TaqMan
Lemmens [23]	2009	Belgian	Caucasian	rs10757278	IS per WHO criteria	Sex, ethnicity	636/809	Population	Taqman
Karvanen [24]	2009	European	Caucasian	rs1333049	IS per ICD-9 criteria	Age, sex, ethnicity, site of enrolment	209/2064	Population	MassArray
Ikram [25]	2009	European	Caucasian	rs1537378	CT or MRI confirmed	Age, ethnicity	1164/18438	Population	Chip
Luke [26]	2009	Austrian	Caucasian	rs10757274	CT or MRI confirmed	Ethnicity	503/784	Population	Kinetic PCR
Yamagishi [27]	2009	American	Caucasian, African American	rs10757274	IS per ICD-9 criteria	Ethnicity	524/12856	Population	Taqman
Ding [28]	2009	Chinese	East Asian	rs10757278	IS per ICD-9 criteria	Ethnicity, resident area	999/1055	Population	TaqMan
Wahlstrand [29]	2009	Swedish	Caucasian	rs10757278	IS patients	Ethnicity, time of follow-up	163/5099	Hospital	MassArray
Hu [30]	2009	Chinese	East Asian	rs2383206	CT or MRI confirmed	Ethnicity	352/423	Hospital	SNPstream
Plant [31]	2011	American	Caucasian	rs10757278	CT or MRI confirmed	Age, sex, ethnicity	229/229	Population	Taqman
Olsson [32]	2011	Swedish	Caucasian	rs10757278	CT or MRI confirmed	Age, sex, ethnicity	834/665	Population	Golden Gate
Lin [33]	2011	Chinese	East Asian	rs1333049	IS per WHO criteria	Ethnicity	642/1361	Population	Taqman
Bellenguez [34]	2012	European, American	Caucasian	rs2383207	CT or MRI confirmed	Age, sex, ethnicity	1780/12253	Population	Chip
Traylor [35]	2012	European	Caucasian	rs2383207	CT or MRI confirmed	Ethnicity	12389/65004	Population	Chip, Taqman
Cheng [36]	2012	European, American	Caucasian	rs4977574	CT or MRI confirmed	Age, sex, ethnicity	6865/11395	Population	KASPar, Taqman
Zhang [37]	2012	Chinese	East Asian	rs10757278	IS per WHO criteria	Age, sex, resident area	1195/1664	Population	LDR
Heckman [38]	2013	American	Caucasian, African American	rs2383207	IS per WHO criteria	Ethnicity	879/824	Population	MassArray