Genetic susceptibility and environmental factors of esophageal cancer in Xi’an

Table 7 Interaction of CYP1A1 Val/Val genotype and a family history of esophageal cancer

ECFH	CYP1A1 Val/Val	Case	Control	OR	OR95%CI	χ2	P
No	No	65	74	1.00
No	Yes	35	19	2.10	1.04-4.24	5.05	0.03
Yes	No	12	5	2.73	0.84-10.38	3.42	0.06
Yes	Yes	15	3	5.69	1.50-31.72	8.47	0.00

SIA = 5.69 / (2.73 + 2.10 - 1.00) = 1.49.