Table 1. Characteristics of eligible case-control studies included in this meta-analysis.

First author	Year	Country	Ethnicity	Source of controls	Genotyping method	Number (case/control)	HWE	NOS score
Zhao et al. [19]	2014	China	Asians	HB	MALDI-TOFMS	308/308	Yes	7
Li et al. [20]	2009	China	Asians	PB	PCR-DHPLC	192/191	Yes	8
Zhou et al. [15]	2010	China	Asians	PB	PCR-DHPLC	201/199	Yes	8
Yuan et al. [21]	2016	China	Asians	PB	PCR-DHPLC	161/161	No	8
Hidaka et al. [22]	2015	Japan	Asians	PB	TaqMan	457/457	Yes	8
Yang et al. [23]	2016	Korea	Asians	HB	MassARRAY	450/1050	Yes	7
Cao et al. [24]	2010	China	Asians	PB	PCR-DHPLC	382/382	Yes	8
Chen et al. [25]	2016	China	Asians	HB	PCR-RFLP	246/274	Yes	7
Zhang et al. [26]	2017	China	Asians	HB	TaqMan	2686/3675	Yes	7
Matsuo et al. [10]	2013	Japan	Asians	HB	TaqMan	697/1372	Yes	7
Chang et al. [27]	2014	China	Asians	PB	PCR-RFLP	196/393	Yes	8
Shin et al. [9]	2011	Korea	Asians	HB	PCR-RFLP	445/370	Yes	8

PB: Population-based; HB: Hospital-based; HWE: Hardy-Weinberg equilibrium; NOS: Newcastle-Ottawa Scale; PCR-RFLP: polymerase chain reaction-restriction fragment length polymorphism; MALDI-TOF-MS: polymerase chain reaction–matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; DHPLC: denaturing high performance liquid chromatography.