Economic Geographic Determinants of Alcohol-Related Problems Among Lower Income Populations

Introduction: The aim of this study was to test a set of theoretical macro-level causal mechanisms that combine to produce greater incidence of alcohol-related problems in lower income areas. We proposed a two-stage mechanism: (i) the economic geographic processes common to all retail markets produce greater concentrations of alcohol outlets in lower income areas; and, (ii) alcohol-related trauma occurs with greater frequency in areas with greater concentrations of alcohol outlets. We tested this proposed mechanism using a mathematical simulation.

Methods: We constructed a spatial plane partitioned into spatial units, assigning uniform populations and income to each unit. We distributed alcohol outlets across spatial units according to the population and income of local and surrounding units using parameter estimates from our previous studies in this area. We then estimated the occurrence of alcohol-related problems based on alcohol outlet densities within local and surrounding units. After perturbing the income for one spatial unit, we observed relative rates of problems in all spatial units. Having obtained these observations for a hypothetical spatial plane, we then repeated the analysis with a spatial plane representing the city of Melbourne, Australia. For this analysis we assigned population and income based on Census demographic characteristics, and perturbed income for specific areas, observing relative rates of alcohol-related problems in local and surrounding areas.

Results: Regarding the first stage of our proposed macro-social mechanism, as income in a local spatial unit increased, the density of alcohol outlets decreased locally but increased in surrounding units. Because, per the second stage of our proposed mechanism, greater concentrations of alcohol outlets were related to greater occurrence of alcohol-related problems in local and surrounding areas, these conditions produced greater relative rates of problems in lower income areas. The results of this simulation were replicated in spatial units representing the city of Melbourne.

Conclusions: Increased risk for alcohol-related problems in lower income areas appears at least partly due to the economic geographic processes that produce greater concentrations of alcohol outlets in these areas. These processes are inevitable, and absent appropriately targeted interventions (e.g. restrictions on alcohol outlet density), lower income populations with continue to experience increased risks.