Covariates assessed in the analyses include age, age of onset of drinking, family history of alcohol problems (first degree relative identified as “ever an alcoholic or problem drinker”), and alcohol consumption (typical number of drinks in a day during the heaviest drinking period). These covariates were chosen based on findings from prior literature. Age, particularly younger age, is associated with increased rates of drinking and increased prevalence of alcohol use disorders with an estimated lifetime prevalence of alcohol dependence of 17% in 18-29 years olds compared to 11% in 45 -64 year olds (Hasin et al., 2007). Multiple studies have shown that risk for lifetime alcohol dependence is higher in those with familial alcoholism (Dawson et al., 1992; Heath et al., 1997) and in those who initiated drinking at an earlier age (Dawson et al., 2008; DeWit et al., 2000; Hingson and Zha, 2009). The consumption variable we chose, “number of drinks of any alcohol usually consumed on days when drank alcohol during period of heaviest drinking,” was selected because it was felt to be most representative of individuals’ typical
