Stores that sell alcohol magnify violence problems in all neighborhoods where they're concentrated. The density of bars, on the other hand, intensifies violence only in communities prone to violence, while moderating violence in quieter neighborhoods, according to a new study.

Researchers examined data on violence throughout California, and found that the most troubled areas were poor urban neighborhoods and rural towns, places where community disorganization, poverty and residential instability were highest. In such locations, the concentration of both stores that sell alcohol and bars magnifies the communities' existing violence problems. Alcohol outlets are typically concentrated in relatively poor areas of communities.

"The regulation of alcohol outlets in violence-prone areas clearly is an important step to reducing crime," said Paul Gruenewald, Ph.D., lead author of the study published in May in the journal Addiction. "In areas where bars are a particular problem, special effort should be made to reduce the potential for violence in these establishments."

The study showed a clear difference between the impact of stores that sell alcohol and bars in some neighborhoods. Density of stores that sell alcohol increased violence in a wide array of neighborhoods, rich and poor. A greater number of bars strongly increased violence in unstable poor and rural areas, but not in wealthy neighborhoods or established immigrant Hispanic neighborhoods.

Researchers suggested that bars in these neighborhoods could have different uses than bars in neighborhoods prone to violence. In neighborhoods with existing violence problems, bars can accelerate violence rates. But in quiet neighborhoods, they generally don't.

Data on population and neighborhood characteristics were collected for all 1,637 zip code areas in California. Information included hospital discharges that resulted from assault for patients 15 years and older. Census data were used to determine levels of education, unemployment, poverty, race and ethnicity, transience among residents and the proportion of the population 15-29 years of age (the group most likely to be involved in assaults).

Gruenewald is science director at PIRE Prevention Research Center. PIRE, or Pacific Institute for Research and Evaluation, is a national nonprofit research institute with centers in seven cities and funded mostly by federal research grants and contracts. This study was funded by the National Institute on Alcohol Abuse and Alcoholism.

For more information, contact Jim Gogek at (301) 755-2445 or jgogek@pire.org.