CYP2E1 Rsa I polymorphism impacts on risk of colorectal cancer association with smoking and alcohol drinking

Table 1 Background characteristics of colorectal cancer cases and their controls

	Controls n (%)	Colorectal cancer n (%)	Colon cancer n (%)	Rectal cancer n (%)
All of the subjects	439 (100.0)	315 (100.0)	105 (100.0)	210 (100.0)
Gender
Males	223 (50.8)	190 (60.3)	65 (61.9)	125 (59.5)
Females	216 (49.2)	125 (39.7)	40 (38.1)	85 (40.5)
χ2MH (P)		6.70 (0.010)	4.19 (0.041)	4.34 (0.037)
Age (yr)
< 40	42 (9.6)	44 (14.0)	14 (13.3)	30 (14.3)
40-49	75 (17.1)	54 (17.1)	15 (14.3)	39 (18.6)
50-59	150 (34.2)	88 (27.9)	30 (28.6)	58 (27.6)
60-69	131 (29.8)	85 (29.0)	26 (24.8)	59 (28.1)
> 70	41 (9.3)	44 (14.0)	20 (19.1)	24 (11.4)
χ2MH (P)		9.37 (0.053)	10.23 (0.037)	5.69 (0.224)
Mean age ± SD	55.7 ± 11.0	55.3 ± 12.7	56.4 ± 13.4	54.7 ± 12.3
P (t test)		0.6172	0.6325	0.3159
Smoking status
Nonsmoker	284 (64.7)	176 (55.9)	61 (58.1)	115 (54.8)
Courrent and former	155 (35.3)	139 (44.1)	44 (41.9)	95 (45.2)
χ2MH (P)		5.99 (0.014)	1.59 (0.208)	5.91 (0.015)
Alcohol status
Nondrinker	327 (74.5)	176 (55.9)	65 (61.9)	120 (57.1)
Current and former	112 (25.5)	139 (44.1)	50 (38.1)	90 (42.9)
χ2MH (P)		28.58 (0.000)	14.19 (0.000)	19.90 (0.000)
CYP 2E1 genotypes1
c1/c1	266 (61.4)	185 (59.1)	63 (60.6)	122 (58.4)
c1/c2	154 (35.6)	106 (33.9)	35 (33.7)	71 (34.0)
c2/c2	13 (3.0)	22 (7.0)	6 (5.8)	16 (7.7)
χ2MH (P)		6.58 (0.037)	1.91 (0.385)	7.07 (0.029)

¹Six controls and two cases were excluded because of unknown CYP2E1 genotype.

Table 2 CYP2E1 genotypes and risk of colorectal cancer

	Genotype	Cases (n)	Controls (n)	OR1 (95% CI)	OR2 (95% CI)
Colorectal cancer
	c1/c1	185	266	1.00	1.00
	c1/c2	106	154	0.99 (0.72-1.35)	0.99 (0.72-1.35)
	c2/c2	22	13	1.54 (1.07-2.19)	1.55 (1.08-2.22)
Colon Cancer
	c1/c1	63	266	1.00	1.00
	c1/c2	35	154	0.96 (0.61-1.52)	0.95 (0.60-1.51)
	c2/c2	6	13	1.36 (0.82-2.25)	1.40 (0.84-2.33)
Rectal cancer
	c1/c1	122	266	1.00	1.00
	c1/c2	71	154	1.01 (0.71-1.44)	1.01 (0.71-1.44)
	c2/c2	16	13	1.61 (1.09-2.36)	1.64 (1.12-2.41)

¹ORs were adjusted for age and sex in a logistic regression model.

²ORs were adjusted for age, sex and status of smoking and alcohol drinking.

Table 3 Logistic regression analysis on smoking, alcohol drinking and CYP2E1 c2/c2 genotypes and risk of colorectal cancer

	Colorectal cancer OR1 (95% CI)	Colon cancer OR1 (95% CI)	Rectal cancer OR1 (95% CI)
Smoking	1.01 (0.69-1.47)	0.84 (0.49-1.44)	1.08 (0.70-1.67)
Alcohol drinking	1.91 (1.31-2.80)	1.68 (0.97-2.89)	2.08 (1.36-3.19)
CYP2E1 c2/c2	1.50 (1.05-2.15)	1.34 (0.81-2.23)	1.58 (1.08-2.32)

¹Logistic regression model included age (continuous), sex, smoking (nonsmoker, current + former smoker), alcohol drinking (nondrinker, current + former drinker) and CYP2E1 genotype (c1/c1 + c1/c2, c2/c2).

Table 4 Interaction between the CYP2E1 genotype and the status of smoking and alcohol drinking, and the odds ratios (ORs) for colorectal cancer

	CYP2E1 genotype	Controls n	Colorectal cancer		Colon cancer		Rectal cancer
			n	OR1 (95% CI)	n	OR1 (95% CI)	n	OR1 (95% CI)
Smoker
No	c1/c1 + c1/c2	275	162	1.00	57	1.00	105	1.00
No	c2/c2	5	14	2.20 (1.31-3.70)	4	1.95 (0.99-3.86)	10	2.30 (1.32-3.99)
Yes	c1/c1 + c1/c2	145	129	1.34 (0.93-1.92)	41	1.11 (0.66-1.88)	88	1.48 (0.98-2.25)
Yes	c2/c2	8	8	1.41 (0.50-3.96)	2	0.91 (0.18-4.57)	6	1.75 (0.57-5.42)
Drinker
No	c1/c1 + c1/c2	313	174	1.00	62	1.00	112	1.00
No	c2/c2	9	10	1.41 (0.89-2.24)	2	1.09 (0.50-2.38)	8	1.55 (0.95-2.53)
Yes	c1/c1 + c1/c2	107	117	1.86 (1.28-2.68)	36	1.50 (0.89-2.55)	81	2.07 (1.37-3.14)
Yes	c2/c2	4	12	5.42 (1.65-17.40)	4	4.74 (1.10-20.40)	8	5.75 (1.65-20.05)

¹ORs were adjusted for age and sex.