Alcohol Outlet Density and Alcohol Use and Problems: Evidence for Gene-Environment Interaction?

The most widely-discussed contributor to the “alcohol environment” is availability, and one of the key contributors to availability is the density of alcohol outlets in one’s community. However, studies of alcohol... [ view full abstract ]

The most widely-discussed contributor to the “alcohol environment” is availability, and one of the key contributors to availability is the density of alcohol outlets in one’s community. However, studies of alcohol involvement that have incorporated gene–environment interactions have tended to emphasize the social and demographic characteristics of individuals or families rather than characteristics of the community- or neighborhood-level alcohol environment. The goal of this study was to examine whether living in a community with more alcohol outlets would facilitate the expression of the genetic propensity to drink and to develop alcohol-related problems in a genetically-informed national survey of United States young adults.  The participants were 1,751 18-26 year-old twin, full-, and half-sibling pairs from Wave III of the National Longitudinal Study of Adolescent to Adult Health.  Participants completed in-home interviews in which alcohol use and problems were assessed. Alcohol outlet densities were extracted from state-level liquor license databases, aggregated at the census tract level, and divided by the total land area for each census tract to derive the density of outlets.  We examined whether estimates of genetic and environmental influences on alcohol use and problems varied as a function of the density of alcohol outlets in the community.  Because the distribution of outlet densities across the United States is extremely skewed and they may only exert an effect at high levels, we dichotomized outlet densities at above (mean of 29 outlets per square kilometer) and below (mean of 1.5 outlets) the top decile.  There was evidence to suggest that alcohol outlet density moderated the genetic diathesis to develop alcohol-related problems; the age- and sex-adjusted heritabilities were 67% and 16% in high- and low-outlet-density communities, respectively.  The results for other alcohol outcomes and for different types of alcohol outlets will be presented and limitations of this study will be discussed.