Table 4.

Gene–environment interactions of XRCC1 and OGG1 polymorphisms together with smoking and alcohol drinking on cholangiocarcinoma risk in Khon Kaen, Thailand

	Smoking	Cases	Controls					Smoking	Cases	Controls
XRCC1	Use of alcohol	n	n	OR*	95% CI	p Value	OGG1	Use of alcohol	n	n	OR*	95% CI	p Value
G399A	All cigarettes smoking					0.87†	C326G	All cigarettes smoking					0.54†
GG	Non-smoker	22	71	1.0			CC	Non-smoker	14	55	1.0
GA	Non-smoker	48	99	1.5	0.82 to 2.79	0.18	CG	Non-smoker	49	122	1.5	0.77 to 2.99	0.22
AA	Non-smoker	2	11	0.6	0.11 to 2.74	0.47	GG	Non-smoker	1	1	–	–	–
GG	Smoker	40	78	2.8	1.30 to 5.91	0.01	CC	Smoker	20	40	3.1	1.17 to 8.38	0.02
GA	Smoker	46	70	3.4	1.60 to 7.28	0.001	CG	Smoker	60	107	4.3	1.79 to 10.21	0.001
AA	Smoker	2	10	1.2	0.21 to 6.29	0.86	GG	Smoker	1	4	1.5	0.14 to 15.44	0.74
G399A	Units of alcohol per month of all alcohol drinking					0.80†	C326G	Units of alcohol per month of all alcohol drinking					0.74†
GG	Non-drinker	16	83	1.0			CC	Non-drinker	10	65	1.0
GA	Non-drinker	20	33	4.4	1.81 to 10.83	0.001	CG	Non-drinker	9	9	8.1	2.30 to 28.36	0.001
AA	Non-drinker	26	33	9.2	3.65 to 23.21	<0.001	GG	Non-drinker	15	21	8.6	2.62 to 28.02	<0.001
GG	<14	22	102	1.1	0.49 to 2.28	0.89	CC	<14	24	130	1.3	0.55 to 3.20	0.52
GA	<14	39	35	8.8	3.76 to 20.71	<0.001	CG	<14	46	58	7.0	2.85 to 17.39	<0.001
AA	<14	33	32	10.3	4.14 to 25.80	<0.001	GG	<14	39	41	11.2	4.18 to 30.17	<0.001
GG	≥14	1	12	0.4	0.05 to 3.71	0.44	CC	≥14	0	1	–	–	–
GA	≥14	2	3	2.8	0.31 to 25.41	0.36	CG	≥14	1	1	7.7	0.29 to 26.73	0.22
AA	≥14	1	6	2.5	0.25 to 23.99	0.44	GG	≥14	1	3	6.4	0.48 to 86.72	0.16

*Crude OR from matched case–control analysis.

†p Value for interaction.