Table 1.

Characteristics of CYP1A1 MspI polymorphism included in the meta‐analysis

	Year	Ethnicity	Source	Case				Control				Method	Sample size	P for HWE	OR 95% CIa		Adjustment of variables
				N	Genotypes			N	Genotypes						CT/TT	CC/TT
					TT	TC	CC		TT	TC	CC
MspI
EC
Jain et al.	2007	Asian	PB	171	59	83	19	201	79	99	23	PCR	≥300	0.629	1.1 (0.71–1.7)	1.1 (0.55–2.2)	Age, gender, smoking, drinking
Malik et al.	2010	Asian	PB	135	76	52	7	195	95	88	12	MLPA	≥300	0.361	0.72 (0.45–1.14)	0.70 (0.26–1.87)	Age, gender
GC
Ma et al.	2006	Asian	PB	60	26	27	7	57	26	28	3	PCR‐RFLP	<300	0.423	–	–	–
Malik et al.	2009	Asian	HB	108	60	46	2	195	95	88	12	PCR	≥300	0.361	0.84 (0.52–1.37)	0.34 (0.07–1.60)	Age, gender
Luo et al.	2011	Asian	PB	123	38	61	24	129	47	54	28	PCR‐RFLP	<300	0.261	–	–	–
Ghoshal et al.	2014	Asian	PB	88	41	36	11	170	78	80	12	PCR‐RFLP	<300	0.370	–	–	–
Darazy et al.	2011	Caucasian	PB	11	9	0	2	56	54	1	1	PCR‐RFLP	<300	0.000	0.87 (0.5–1.5)	1.8 (0.7–4.4)	Age, gender
CC
Sivaraman et al.	1994	Mixed	PB	43	23	10	10	47	23	22	2	PCR‐RFLP	<300	0.508	–	–	–
Ye et al.	2002	Caucasian	NR	41	35	6	0	82	73	9	0	PCR‐RFLP	<300	0.871	–	–	–
Talseth et al.	2006	Caucasian	NR	118	94	20	4	100	91	9	0	PCR‐RFLP	<300	0.895	–	–	–
Darazy et al.	2011	Caucasian	PB	46	42	2	2	56	54	1	1	PCR‐RFLP	<300	0.000	–	–	–
Saeed et al.	2013	Asian	HB	94	70	21	3	79	73	6	0	PCR‐RFLP	<300	0.940	–	–	–
Rudolph et al.	2011	German	PB	679	539	134	6	679	564	102	13	KASPar assays	≥300	0.007	–	–	–

Significance of bold value: P < 0.05 for HWE is considered as significant disequilibrium.

^aAdjusted. EC: oesophageal cancer; GC: gastric cancer; CC: colorectal cancer; HB: Hospital based; PB: Population based; NR: no record; HWE: Hardy–Weinberg equilibrium; PCR‐RFLP: polymerase chain reaction‐restriction fragment length polymorphism; PCR–ASO: PCR–allele specific oligonucleotide.