A novel genetic polymorphism of inducible nitric oxide synthase is associated with an increased risk of gastric cancer

Table 1 Covariate distribution among study subjects and ORs for gastric cancer

	Characteristics	No Cases (%) (n = 165)	No. Controls (%) (n = 295)	OR (95%CI)
Age (yr)
	Mean (yr ± SD)	59.36 ± 9.29a	51.89 ± 10.24
	Min. (yr)	34.72	30.77
	Max. (yr)	81.95	78.21
Gender
	Male (%)	110 (66.67)	190 (64.41)
	Female (%)	55 (33.33)	105 (35.59)
	Ratio	2.00:1	1.81:1
Smoking habit
	Never	60 (36.36)	119 (40.34)	1.00
	Current	44 (26.67)	139 (47.12)	0.26 (0.15–0.46)b
	Past	61 (36.97)	37 (12.54)	3.15 (1.77–5.61)b
Alcohol habits
	Never	97 (58.79)	160 (54.24)	1.00
	Current	18 (10.91)	91 (30.85)	0.18 (0.10–0.35)b
	Past	50 (30.30)	44 (14.92)	1.80 (1.06–3.08)
Plasma H Pylori CagA antibody
	Negative	136 (82.42)	107 (49.31)	1.00
	Positive	29 (17.58)	110 (50.69)	0.18 (0.11–0.31)b
iNOS genotyping
	CC	108 (75.52)	189 (76.83)	1.00
	CT	33 (23.08)	49 (19.92)	1.15 (0.68–1.96)
	TT	2 (1.40)	8 (3.25)	0.42 (0.08–2.16)
	CT + TT	35 (24.48)	57 (23.17)	1.03 (0.59–1.79)

^aP < 0.05 vs control group after adjusted for age and gender,

^bP < 0.01 vs control.

Table 2 Interaction between C/T polymorphism and past cigarette smoking for the risk of gastric cancer

C/T polymo rphism	Past smoking	Total cases (n = 143)	Controls (n = 246)	OR1	95%CI	IGC (n = 93)	OR2	95%CI	GCC (n = 50)	OR3	95%CI
CC	No	67	162	1.00			46	1.00	21	1.00
CT + TT	No	22	51	0.98	0.55-1.78	12	0.75	0.36-1.54	10	1.44	0.63-3.27
CC	Yes	41	27	2.92	1.53-5.57	27	2.47	1.19-5.09	14	3.65	1.42-9.38
CT + TT	Yes	13	6	3.62	1.23-10.64	8	3.06	0.91-10.35	5	4.63	1.15-18.58

¹Adjusted for age and gender, χ²_trend = 26.26, ^df = 1, P = 0.00, γ = 1.29/1.07 = 1.21

²Adjusted for age and gender, χ²_trend = 18.40, ^df = 1, P = 0.00, γ = 1.12/0.90 = 1.24

³Adjusted for age and gender, χ²_trend = 17.53, ^df = 1, P = 0.00, γ = 1.53/1.29 = 1.19.

Table 3 Interaction between C/T polymorphism and past alcohol drinking for the risk of gastric cancer

C/T polymorphism	Past alcohol drinking	Total cases (n = 143)	Controls (n = 246)	OR1	95%CI	IGC (n = 93)	OR2	95%CI	GCC (n = 50)	OR3	95%CI
CC	No	76	157	1.00		53	1.00		23	1.00
CT + TT	No	24	51	0.83	0.46-1.50	13	0.62	0.30-1.28	11	1.22	0.55-2.70
CC	Yes	32	32	1.34	0.72-2.52	20	1.36	0.67-2.75	12	1.27	0.50-3.19
CT + TT	Yes	11	6	3.33	1.14-9.67	7	3.42	1.03-11.35	4	3.25	0.80-13.13

¹Adjusted for age and gender, χ²_trend = 10.29, ^df = 1, P = 0.001, γ = 1.20/0.30 = 4.00

²Adjusted for age and gender, χ²_trend = 5.65, ^df = 1, P = 0.017, γ = 1.23/0.31 = 3.97

³Adjusted for age and gender, χ²_trend = 8.95, ^df = 1, P = 0.003, γ = 1.18/0.24 = 4.9.

Table 4 Interaction between C/T polymorphism and H pylori CagA status for the risk of gastric cancer

C/T polymorphism	CagA antibody	Total cases (n = 143)	Controls (n = 178)	OR1	95%CI	IGC (n = 93)	OR2	95%CI	GCC (n = 50)	OR3	95%CI
CC	No	87	64	1.00		61	1.00		26	1.00
CT + TT	No	28	19	2.53	1.29-4.98	17	2.19	1.01-4.76	11	3.52	1.44–8.61
CC	Yes	21	73	0.45	0.25-0.81	12	0.34	0.17-0.70	9	0.76	0.33-1.73
CT + TT	Yes	7	22	0.43	0.17-1.10	3	0.24	0.07-0.89	4	0.86	0.27-2.79

¹Adjusted for age and gender, χ²_trend = 33.40, df = 1, P = 0.00, γ = -0.84/-0.79 = 1.06 ²Adjusted for age and gender, χ²_trend = 28.53, ^df = 1, P = 0.00, γ = -1.41/-1.08 = 1.31 ³Adjusted for age and gender, χ²_trend = 12.42, ^df = 1, P = 0.0004, γ = -0.15/-0.27 = 0.56.