Genetic and environmental determinants of risk for cholangiocarcinoma in Thailand

Table 2 Effect of modification of alcohol drinking on relationships between smoking, eating fermented fish and risk for cholangiocarcinoma

Variable	Category	Alcohol drinking
		Never drinkers				Ever1 drinkers
		Adjusted2 OR	95%CI		P value	Adjusted2 OR	95% CI		P value
			LL	UL			LL	UL
Smoking	Never	1	Reference			4.25	1.02	17.63	0.05
	Occasional	4.36	0.4	47.49	0.23	1.07	0.06	20.66	0.96
	Ex-regular					9.09	1.27	65.18	0.03
	Regular	3.64	0.19	71.41	0.39	7.99	1.56	40.94	0.01
Pla-ra, Pla-chao	< 3/d	1	Reference			14.07	1.46	135.36	0.02
	≥ 3/d	12.34	1.22	124.75	0.03	20.88	2.27	192.06	< 0.01

¹Including occasional, ex- and currently regular drinkers;

²Adjusted for anti-OV Ab when calculating the OR of smoking, and adjusted for anti-OV Ab and smoking when calculating the OR of eating of fermented fish (pla-ra and/or pla-chao). Nakorn Phanom (Thailand): based on the conditional logistic regression model. CI: Confidence interval; LL: Lower limit; UL: Upper limit; OR: Odds ratio. Adapted from Honjo et al[5] 2005. Allowing for absence of control subject in the category for occasional smoking and absence of case subject in the category for ex-regular smoking among never drinkers, we combined these two categories and confirmed the conclusion in the table is the materially unchanged from that in the table in our previous paper (Honjo et al[5] 2005).