Neighborhood density of alcohol outlets moderates genetic and environmental influences on alcohol problems

Background and Aims: Geographic differences in rates of alcohol use disorder suggest that environmental factors and gene–environment interactions are likely to play an important role in its genesis. We aimed to examine whether living in a community with more alcohol outlets would facilitate the expression of the genetic propensity to develop alcohol problems. Design: Cross-sectional twin/sibling study. Setting: United States. Participants: The participants were 18–26-year-old twin, full- and half-sibling pairs from Wave III of the National Longitudinal Study of Adolescent to Adult Health. Measurements: Participants completed in-home interviews in which past year alcohol problems were assessed. Alcohol outlet densities were extracted from state-level liquor license databases aggregated at the census tract level. Findings: There was evidence that estimates of genetic and environmental influences on alcohol problems varied as a function of the density of alcohol outlets in the community. The heritability of alcohol problems for those residing in a neighborhood with more than 10 on-premises outlets was 78% (95% confidence limits = 52–100%), compared with 11% (95% confidence limits = 0–29%) for those in a neighborhood with no on-premises outlets. This moderating effect of alcohol outlet density was not explained by state of residence, population density or neighborhood socio-demographic characteristics. Conclusions: Individuals who are genetically predisposed to develop alcohol problems may be especially sensitive to the influence of many alcohol outlets in their community.