Table 2.

Single Predictor Cox Proportional Hazards Models. The unadjusted hazard ratio (uHR) predicts the change of the likelihood of alcohol initiation corresponding to a unit increase in each predictor. A predictor with a Hazard Ratio >1 increases (Hazard Ratio <1 decreases) the likelihood.

Source	Predictor Variables	Unadjusted HR (95% CI) p value
Original	Number of non-Alcohol Related Conduct Disorder Symptoms	1.23 (1.11, 1.35)***
	Membership High-Risk Alcohol Dependent Family	1.63 (1.13, 2.34)*
	Most Best Friends Drank	3.25 (2.64, 4.00)***
	Achenbach Youth Self Report Externalizing Score	1.06 (1.05, 1.07)***
	Achenbach Youth Self Report Social Problems Score	1.05 (1.01, 1.09)**
Covariates	Male versus Female	1.16 (0.93, 1.45)
	Interview Age in Years	1.20 (1.07, 1.35)**
	Ancestry: European versus African Americans	1.32 (1.03, 1.70)*
GABRA2 rs279871	Number of Thymine Alleles	1.12 (0.94, 1.33)
	Homozygous Thymine Genotype	1.27 (1.02, 1.58)*

^*p < 0.05;

^**p < 0.01,

^***p < 0.001