Genetic polymorphisms of ADH2 and ALDH2 association with esophageal cancer risk in southwest China

Table 1 Characteristics of patients and controls n (%)

Characteristic	Patients n = 191	Controls n = 198	P1	OR (95% CI)2
Age (yr)
< 50	28 (14.7)	84 (42.9)
50-64	118 (61.7)	67 (33.4)	P < 0.001	-
≥ 65	45 (23.6)	47 (23.7)
Mean age (SD)	58.3 (8.3)	52.8 (13.2)	-	-
Sex
Male	126 (66.0)	122 (61.6)	P = 0.372	-
Female	65 (34.0)	76 (38.4)		-
Smoking status
Non-smokers3	75 (39.3)	121 (61.1)	P < 0.001	1.00 (References)
Current smokers	116 (60.7)	77 (38.9)		3.76 (2.01-6.73)
Alcohol drinking status
Non-drinkers4	80 (41.9)	128 (64.7)		1.00 (References)
Current alcohol drinkers	111 (58.1)	70 (35.3)	P < 0.001	3.16 (1.91-5.24)

¹P value by chi-square test;

²ORs for smoking and drinking were adjusted for age and sex, rapid food eating, quality of drinking water, consumption of fresh fruits, vegetable and eggs;

³Non-smokers including ex-smokers;

⁴Non-drinkers including ex-drinkers.

Table 2 ADH2, ALDH2 genotype and allele frequencies and ORs for esophageal cancer n (%)

ADH2	Cases (n = 191)	Controls (n = 198)	OR (95% CI)1
*2/*2	78 (40.8)	100 (50.5)	1.00 (Reference)
*1/*2	80 (41.9)	76 (38.4)	1.89 (1.10-3.22)
*1/*1	33 (17.3)	22 (11.1)	1.91 (0.92-3.95)
*1/*2 + *1/*1	113 (59.2)	98 (49.5)	1.65 (1.02-2.68)
ALDH2
*1/*1	90 (47.1)	108 (54.5)	1.00 (References)
*1/*2	98 (51.3)	76 (38.4)	1.67 (1.02-2.72)
*2/*2	3 (1.6)	14 (7.1)	0.26 (0.06-1.09)
*1/*2 + *2/*2	101 (52.9)	90 (45.5)	1.43 (0.89-2.30)
Allele frequencies			OR (95% CI)2
ADH2
*2	236 (61.8)	276 (69.7)	1.00 (References)
*1	146 (38.2)	120 (30.3)	1.42 (1.06-1.92)
ALDH2
*1	278 (72.8)	292 (73.7)	1.00 (References)
*2	104 (27.2)	104 (26.3)	1.05 (0.76-1.44)

¹ORs for gene frequencies were adjusted for sex, age, smoking, drinking, rapid food eating, quality of drinking water, consumption of fresh fruits, vegetable and eggs;

²ORs for allele frequencies were not adjusted.

Table 3 Combined effect of alcohol consumption and ADH2 and ALDH2 polymorphisms on esophageal cancer n (%)

ADH2		Alcohol drinking status
		Non-drinkers2			Current alcohol drinkers
		Cases (n = 80)	Controls (n = 128)	OR (95% CI)1	Cases (n = 111)	Controls (n = 70)	OR (95% CI)1
*2/*2		37 (46.3)	65 (50.8)	1.00 (References)	41 (36.9)	35 (50.0)	1.88 (0.86-4.15)
*1/*2 or *1/*1		43 (53.7)	63 (49.2)	1.21 (0.63-2.33)	70 (63.1)	35 (50.0)	3.94 (1.76-8.81)
ALDH2
*1/*1		33 (41.3)	67 (52.3)	1.00 (References)	57 (51.4)	41 (58.6)	3.15 (1.39-7.13)
*1/*2 or *2/*2		47 (58.7)	61 (47.7)	2.03 (1.03-3.99)	54 (48.6)	29 (41.4)	4.82 (2.06-11.27)
ADH2 and ALDH2
*2/*2	*1/*1	15 (18.8)	42 (32.8)	1.00 (References)	17 (15.3)	20 (28.6)	2.54 (0.84-7.67)
*1/*2 or *1/*1	*1/*2 or *2/*2	25 (31.3)	38 (29.7)	2.46 (0.98-6.14)	30 (27.0)	14 (20.0)	9.86 (3.10-31.38)

¹ORs were adjusted for sex, age, smoking, rapid food eating, quality of drinking water, consumption of picked vegetables and fresh fruits, vegetables and eggs;

²Non-drinkers including ex-drinkers.