Table 1.

Characteristics of the studies included in the meta-analysis

First author	Year	Country	Ethnicity	Study design	Genotyping method	Total sample size (Case/control)
Boersma et al16	2006	USA	Caucasian African-American	CC	PCR	290/314
Campbell et al17	2006	UK	Caucasian	CC	PCR	351/258
Millikan et al18	2006	USA	Caucasian African-American	CC	PCR-RFLP	2,037/1,813
Petenkaya et al19	2006	Turkey	Mixed	CC	PCR-RFLP	223/149
Ma et al21	2006	People’s Republic of China	Asian	CC	PCR	366/605
Wilkening et al20	2006	Germany	Caucasian	CC	qPCR	549/1,065
Wasielewski et al22	2007	The Netherlands	Caucasian	CC	PCR	343/126
Cox et al23	2007	America	Mixed	CC	PCR-RFLP	1,519/2,271
Lum et al24	2008	Singapore	Asian	CC	PCR	402/128
Singh et al25	2008	India	Asian	CC	qPCR	104/105
Paulin et al26	2008	England	Caucasian	CC	qPCR	299/275
Krekac et al27	2008	Czech Republic	Caucasian	CC	PCR-RFLP	158/149
Yarden et al28	2008	Israel	Caucasian	CC	qPCR	187/138
Lang et al29	2009	Sweden	Caucasian	CC	PCR-RFLP	123/146
Sun et al30	2009	People’s Republic of China	Asian	CC	PCR-RFLP	124/97
Koh et al31	2011	Singapore	Asian	CC	qPCR	385/614
Leu et al32	2011	People’s Republic of China	Asian	CC	PCR	255/324
Knappskog et al33	2011	WEC, Finland	Caucasian	CC	PCR-RFLP/Taqman	1,973/2,518
Alshatwi et al34	2012	Saudi Arabia	Asian	CC	PCR	100/100

Abbreviations: CC, case–control; PCR, polymerase chain reaction; RFLP, restriction fragment length polymorphism; WEC, Western European countries including the UK, the Netherlands, and Norway; qPCR, quantitative PCR.