Meta-analysis of ADH1B and ALDH2 polymorphisms and esophageal cancer risk in China

Table 1 Characteristics of studies included in meta-analysis

Authors	Origin	HWE of controls	n	Controls
Ding et al[13], 2009	Jiangsu	Yes	191	221
Guo et al[14], 2008	Gansu	Yes	80	480
Lee et al[15], 2008	Taiwan	Yes	406	656
Yang et al[16], 2007	Sichuan	Yes	191	198
Chen et al[17], 2006	Taiwan	Yes	330	592
Wu et al[18], 2005	Taiwan	Yes	134	237
Chao et al[19], 2000	Taiwan	Yes	88	105

HWE: Hardy-Weinberg equilibrium.