FH captures potentially heritable genetic and early family environment effects (Light et al., 1996, Zucker et al., 1994) and is commonly measured by retrospective indicators of alcohol problems in parents or in first-degree relatives (Elliott, Carey, & Bonafide, 2012). Some studies use a degree measure of FH density in both first- and second-degree relatives (Dawson et al., 1992, Harford et al., 1992), while other studies consider both the proportion of affected relatives and level of relatedness (Turner et al., 1993, Stoltenberg et al., 1998, Milne et al., 2008), or presence of affected relatives across multiple generations (Dawson et al., 1992, Hill et al., 1994, Kendler et al., 2018). Studies using these composite FH measures consistently find individuals from more densely-affected families are at greater risk for hazardous alcohol use and AUD. In a US population sample, Dawson et al. (Dawson, Harford, & Grant, 1992) showed odds of AUD among drinkers were highest in individuals from high-density families with alcohol problems in both first- and second- or third-degree relatives (OR = 2.79). Odds of dependence also were higher in those with alcohol problems only in first-degree relatives (OR = 1.91) compared to negative FH (Dawson et al., 1992).
