Association of genetic polymorphisms of aldehyde dehydrogenase-2 with esophageal squamous cell dysplasia

Table 1 Characteristics of cases and controls n (%)

Variables	Controls	Cases	t/χ2	P3
Age (yr)	51.01 ± 8.427	54.89 ± 8.443	-4.567	0.000
Income (yuan/yr per person)	1825 ± 1605	1768 ± 1599	0.350	0.726
Height (cm)	163.71 ± 7.374	164.40 ± 7.225	-0.944	0.346
Weight (kg)	67.08 ± 52.848	61.36 ± 8.027	0.671	0.502
Body mass index (kg/m2)	23.08 ± 2.957	22.68 ± 2.462	1.470	0.142
SBP (mmHg)	132.45 ± 19.852	135.38 ± 20.411	-1.445	0.149
DBP (mmHg)	84.74 ± 13.083	85.27 ± 13.132	-0.406	0.685
Gender
Male	123 (58.0)	124 (67.4)	3.687	0.055
Female	89 (42.0)	60 (184)
Age (yr)
40-49	94 (44.3)	41 (22.3)	22.407	0.000
50-59	81 (38.2)	91 (49.5)
60-69	37 (17.5)	52 (28.3)
Education
Illiteracy	33 (15.6)	34 (18.5)	6.838	0.077
Primary school	54 (25.5)	54 (29.3)
High school	96 (45.3)	85 (46.2)
College and above	29 (13.7)	11 (6.0)
Smoking index1
0	117 (55.2)	81 (44.0)	6.107	0.047
< 500	47 (22.2)	43 (23.4)
≥ 500	48 (22.6)	60 (32.6)
Alcohol drinking status2
0	106 (50.0)	81 (44.0)	2.057	0.358
< 65	48 (22.6)	41 (22.3)
≥ 65	58 (27.4)	62 (33.7)
History of esophageal cancer
No	166 (84.7)	152 (82.6)	0.302	0.582
Yes	30 (15.3)	32 (17.4)
ALDH2
G/G	65 (30.7)	98 (53.3)	25.431	0.000
G/A	106 (50.0)	73 (39.7)
A/A	41 (19.3)	13 (7.1)

¹Smoking index = cigarettes/d × number of smoking years;

²Alcohol ≥ 65 g/d = heavy drinker;

³t test and χ² test were used for quantitative data variables and categorical data variables respectively. SBP: Systolic blood pressure; DBP: Diastolic blood pressure.

Table 2 Association of factors with squamous cell dysplasia of esophagus

Factors	OR (95% CI)1	OR (95% CI)2
Smoking index
0	1.00	1.00
< 500	1.32 (0.80-2.18)	1.19 (0.64-2.24)
≥ 500	1.81 (1.12-2.90)	1.56 (0.83-2.91)
Drinking index
0	1.00	1.00
< 65	1.12 (0.67-1.86)	0.92 (0.49-1.76)
≥ 65	1.40 (0.88-2.22)	1.03 (0.55-1.96)
History of esophageal cancer
No	1.00	1.00
Yes	1.10 (0.66-1.85)	1.08 (0.64-1.83)
ALDH2
A/A	1.00	1.00
A/G	2.17 (1.09-4.34)	2.19 (1.08-4.43)
G/G	4.76 (2.37-9.56)	4.50 (2.21-9.19)

¹Crude OR;

²Adjusted ORs were adjusted for age and gender. OR: Odds ratio; CI: Confidence intervals.

Table 3 Interaction between ALDH2 genotypes and environmental factors for esophageal dysplasia n (%)

Factors	Genotype	Controls	Cases	OR (95% CI)1	OR (95% CI)2
Smoking index	ALDH2
0	A/A	18 (8.5)	3 (1.6)	1.00	1.00
0	G/A	62 (29.2)	33 (17.9)	3.19 (0.88-11.64)	3.10 (0.84-11.45)
0	G/G	37 (17.5)	45 (24.5)	7.30 (1.99-26.71)	6.97 (1.88-25.87)
< 500	A/A	17 (8.0)	3 (1.6)	1.06 (0.19-5.99)	0.98 (0.17-5.77)
< 500	G/A	22 (10.4)	19 (10.3)	5.18 (1.32-20.35)	4.70 (1.16-19.07)
< 500	G/G	8 (3.8)	21 (11.4)	15.75 (3.63-68.41)	13.10 (2.85-62.14)
≥ 500	A/A	6 (2.8)	7 (3.8)	7.00 (1.36-36.01)	6.84 (1.25-37.36)
≥ 500	G/A	22 (10.4)	21 (11.4)	5.73 (1.47-22.33)	5.03 (1.21-20.82)
≥ 500	G/G	20 (9.4)	32 (17.4)	9.60 (2.50-36.81)	7.78 (1.92-31.53)
Drinking index	ALDH2
0	A/A	20 (9.4)	8 (4.3)	1.00	1.00
0	G/A	50 (23.6)	34 (18.5)	1.70 (0.67-4.30)	1.98 (0.75-5.25)
0	G/G	36 (17.0)	39 (21.2)	2.71 (1.06-6.91)	3.16 (1.19-8.41)
< 65	A/A	12 (5.7)	3 (1.6)	0.63 (0.14-2.82)	0.65 (0.19-3.09)
< 65	G/A	27 (12.7)	15 (8.2)	1.39 (0.48-3.91)	1.19 (0.40-3.50)
< 65	G/G	9 (4.2)	23 (12.5)	6.39 (2.07-19.69)	5.05 (1.57-16.15)
≥ 65	A/A	9 (4.2)	2 (1.1)	0.56 (0.10-3.16)	0.43 (0.07-2.52)
≥ 65	G/A	29 (13.7)	24 (13.0)	2.07 (0.78-5.23)	1.70 (0.60-4.80)
≥ 65	G/G	20 (9.4)	36 (19.6)	4.50 (1.68-12.06)	3.19 (1.12-9.28)
History of esophageal cancer	ALDH2
No	A/A	31 (15.8)	10 (5.4)	1.00	1.00
No	G/A	82 (41.8)	61 (33.2)	2.31 (1.05-5.06)	2.23 (1.01-4.93)
No	G/G	53 (27.0)	81 (44.0)	47.74 (2.15-10.47)	4.30 (1.93-9.62)
Yes	A/A	9 (4.6)	3 (1.6)	1.03 (0.23-4.58)	0.88 (0.20-4.01)
Yes	G/A	14 (7.1)	12 (6.5)	2.66 (0.93-7.59)	2.37 (0.82-6.89)
Yes	G/G	7 (3.6)	17 (9.2)	7.53 (2.42-23.37)	7.11 (2.25-22.45)

¹Crude OR;

²Adjusted ORs were adjusted for age and gender. OR: Odds ratio; CI: Confidence intervals.