Table 1

Characteristics of studies included in meta-analysis

First author	Years	Country	Ethnicity	Case number	Control number	Newcastle-Ottawa score	Genotyping
Griaga	2007	Germany	European	259	489	7/9	PCR-RFLP
Shiroeda	2010	Japan	Asian	111	209	6/9	PCR-SSCP
Fei	2008	China	Asian	99	142	9/9	PCR-RFLPtetra-primer ARMS
Oliver	2007	Spain	European	1295	887	8/9	PCR-RFLP
Przybyłowska	2011	Poland	European	99	123	6/9	PCR-RFLP
Nohara	2004	Japan	Asian	221	438	7/9	PCR-RFLPPCR-SSCP

ARMS, amplification refractory mutation system; PCR-RFLP, PCR-restriction fragment length polymorphism; PCR-SSCP, PCR-single-strand conformation polymorphism.