Table 3. Meta-analysis of the GSTT1 null genotype and esophageal cancer risk.

	Number of Study	OR (95%CI)	P	P (Q-test)	I-squared
Total	30	1.20 (1.04–1.40)	0.014	0.000	60.2
Ethnicity
Asians	18	1.33 (1.12–1.58)	0.001	0.003	54.9
Caucasians	10	0.91 (0.65–1.26)	0.569	0.01	58.3
Africans	2	1.32 (0.98–1.77)	0.070	0.157	50.0
ESCC	21	1.34 (1.12–1.61)	0.001	0.000	62.6
Ethnicity
Asians	13	1.54 (1.30–1.82)	0.000	0.097	35.7
Caucasians	6	0.87 (0.48–1.57)	0.640	0.002	73.5
Africans	2	1.32 (0.98–1.77)	0.070	0.157	50.0
EADC	8	0.98 (0.71–1.35)	0.911	0.240	23.7