PCs of population stratification (PC1–PC4). All HRs show the effect of a particular variable after accounting for the effects of all other variables.EA, European ancestry; HR, hazard ratio; PC, principal component; PRS, polygenic risk score.Table 3Cox Proportional Hazards Model for Sex, PRSs (EA_MAX_ALC.P1), Family Type (Case/Comparison), Age of First Drink, Peer Drinking, and Comorbidity in EA Subjects: Analysis of Maximum Likelihood EstimatesParameterParameter EstimateStandard Errorχ21p ValueHazard Ratio95% Confidence LimitsSex−0.202810.068548.75503.09 × 10−30.8160.714–0.934EA_MAX_ALC.P1 (With PC1–PC4)0.131710.0355413.73112.11 × 10−41.1411.064–1.223Family Type0.160130.112872.01281.56 × 10−11.1740.941–1.464Age of First Drink−0.150560.01239147.69705.53 × 10−340.8600.840–0.881Peer Drinking0.688930.0747185.03992.92 × 10−201.9921.720–2.306Comorbidity Both0.303690.106338.15784.29 × 10−31.3551.100–1.669 Externalizing only0.329660.0774918.09742.10 × 10−51.3901.195–1.619 Internalizing only−0.117560.159370.54424.61 × 10−10.8890.651–1.215The model is also adjusted for ancestry using the first four PCs of population stratification (PC1–PC4). All hazard ratios show the effect of a particular variable after accounting for the effects of all other variables.EA, European ancestry; PC, principal component; PRS, polygenic risk score.
