Family history of alcohol problems was assessed by asking respondents whether any of their blood relatives have ever been a “problem drinker or alcoholic”, with affirmative responses followed by a checklist of relatives. For this study, FH was implemented as a four-level variable: negative history (referent); extended family only (grandparents, aunts/uncles, cousins); first-degree relatives only (parents, siblings); and both first-degree and extended family (high FH density) (Dawson et al., 1992, Hill et al., 1994, Kendler et al., 2018). Measures of degree of FH provide more information than dichotomous parental or first-degree relative measures, as increases in an outcome measure with greater cumulative levels of FH imply genetic effects (Hill, Blow, Young, & Singer, 1994).
