Glutathione S-transferase M1 polymorphism and esophageal cancer risk: An updated meta-analysis based on 37 studies

Table 2 Main results of the pooled odds ratios in this meta-analysis

	Null vs present
	No. of studies	OR	95%CI	P value
Total	37	1.33	1.12-1.57	0.00001
Ethnicity
Asian	27	1.53	1.26-1.86	0.00001
Caucasian	8	1.02	0.87-1.19	0.97
Histological type
ESCC	22	1.15	0.91-1.45	0.00001
EADC	8	0.98	0.81-1.18	0.93
NR	12	1.82	1.58-2.09	0.007
Smoking status
Smokers	6	0.97	0.53-1.77	0.00001
Nonsmokers	6	0.97	0.57-1.64	0.001
Histological type of Caucasian
ESCC	5	1.15	0.91-1.45	0.33
EADC	8	0.98	0.81-1.18	0.93

The P value for heterogeneity. ESCC: Esophageal squamous cell carcinoma; EADC: Esophageal adenocarcinoma; NR: Not reported.