We conducted a series of logistic regression analyses, controlling for gender, with alcohol dependence diagnosis as the dependent variable. We first confirmed that a history of CSA is associated with lifetime alcohol dependence risk (OR 2.03; 95%CI 1.40 – 2.92); we again found no evidence of a significant main effect for H2 haplotype on risk for alcohol dependence (OR 0.92; 95%CI 0.70 – 1.21). We next included a term for the G × E interaction involving CSA and the H2 haplotype in a model that also contained terms for main effects of CSA history, gender, and H2 haplotype. We found evidence of a significant G × E interaction for the H2 haplotype protecting against CSA-associated effects on alcohol dependence risk (OR 0.42; 95%CI 0.20 – 0.89; p=0.023). We calculated alcohol dependence risk by CSA status, controlling for gender, separately for individuals with and without the H2 haplotype. For H1 homozygotes (N=677), significant alcohol dependence risk was associated with CSA (OR 3.37; 95%CI 2.03 – 5.59). For those with the H2 haplotype (N=451), no evidence was found of CSA-associated risk (OR 1.04; 95%CI 0.57 – 1.90).
