Table 2.

Odds Ratios for the Joint Association of Prostate Stem Cell Antigen Gene (PSCA) Polymorphism rs2294008 and Smoking Status With Bladder Cancer Risk^a

Method	PSCA Genotype	Smoking Status				RERIb	95% CI	Interaction P Value
		Never Smoker		Ever Smoker
		OR	95% CI	OR	95% CI
No G-E independence assumption	CC	1	Referent	2.53	2.03, 3.14b	0.53	0.17, 0.88	0.0076
(prospective likelihood)	CT + TT	1.05	0.86, 1.30	3.11	2.54, 3.81
G-E independence assumption	CC	1	Referent	2.55	2.10, 3.09	0.53	0.23, 0.83	0.0010
(retrospective likelihood)	CT + TT	1.07	0.89, 1.28	3.15	2.59, 3.83

Abbreviations: CI, confidence interval; G-E, gene-environment; OR, odds ratio; RERI, relative excess risk due to interaction.

^a Data were obtained from a National Cancer Institute-led genome-wide association study that included 3,577 cases and 5,280 controls from 5 different study centers (14).

^b RERI is a measure of additive interaction defined as .