Objective: This study examines whether the association between violence and population density is moderated by the presence of alcohol outlets, both within a target geographical area and in adjacent geographical areas. The effect of sociodemographic variables on violence is also examined controlling for spatial confounding.
Method: Zip code areas (N = 766) in California from four distinct areas (three urban and one rural) were examined for rates of violence, taking into consideration population characteristics of persons living in those areas and the potential interaction effects of alcohol outlets on violence rates. Population characteristics were assessed using Census data: outlet densities were obtained from the California Department of Alcohol Beverage Control; and violence rates were abstracted from hospital discharge data. A spatial population model of the production of violence was used to examine the relationships of population characteristics of target and surrounding areas to violence rates.
Results: The density of bars was found to be strongly associated with greater rates of assault, while density of restaurants was associated with less violence. Both appeared to have greatest effect in densely populated areas. Local and nearby population characteristics were also found to be related to greater rates of violence.
Conclusions: While limited to cross-sectional data, the current study suggests that alcohol outlets, in the presence of socioeconomic measures, moderate the occurrence of violence in urban areas.