Tuesday, April 14, 2009

Gun Violence and Public Health

The blood had not yet dried in the lecture rooms of Virginia Tech, Blacksburg, Virginia, before polarized camps claimed that the slaughter of 32 students and teachers vindicated their particular stance on gun control. So shrill was the debate about whether the tragedy would have been better prevented by reducing firearms through stronger gun laws or by increasing availability through liberalizing right-to-carry legislation, that the more important issue of gun violence as a public-health menace has been neglected.

Until the debate widens to address violence as a preventable social problem, rather than solely a legal concern, mass shootings will continue. To pretend that the Blacksburg tragedy is unique ignores the legacy of school shootings in Dunblane, Columbine, and elsewhere, and deprives people of an opportunity to reduce future risks.

Violence is a broad problem that involves communities, not just criminals, and populations around the world, not just the USA. In 2003, 1.6 million people were killed by violence worldwide, more than by road traffic crashes or malaria. One-third died as a result of homicide. The incidence is rising, fuelled by inequalities, victimization, and lack of social trust, so that gunshot wounds are a major cause of death for young men.

Because the USA has the highest homicide and gun-homicide rates of any industrialized democracy, the country is a natural focus for attempts to learn more about violence. But despite many federally funded programs, objective research on interventions to reduce violence is lacking. Nor has the Campbell Collaboration, established to synthesize evidence for the social sciences, provided guidance. In 2004, the US National Research Council critically reviewed gun violence and concluded that there was little quality science to inform decision making. The reason is that most studies are based on associations or on before-and-after series.

A 2004 survey from Harvard estimated that 38% of households and 26% of individuals had at least one of the 283 million private firearms in the USA. Even teenagers report ready access to guns. Several studies in the USA and elsewhere cite protection as the main reason for having a gun, despite the fact that guns are far more likely to be used offensively, including suicide, than for self-defense. The association of firearms and their use in homicide between populations (four shooting deaths per 100 000 in the USA vs 0.15 per 100000 in Cameroon where private guns are banned) is complex and obviously involves cultural factors as well.

Yet, interventions within populations that remove guns do seem to reduce gun crime in a reproducible manner. In 2003, more than half the guns retrieved from crimes were traced to 1% of dealers. When such a dealer in Milwaukee stopped selling inexpensive handguns, local gun crime was reduced by 96% and the transfer of new weapons to criminals decreased by 44%. In Indianapolis, Pittsburgh, and Kansas City, policing to remove illegal firearms from the street reduced gun crime as well. Multiple interventions combining social networks with stronger enforcement can also be successful, such as the 63% drop in homicides after Operation Ceasefire in Boston. Tougher gun laws in Brazil in 2003, allied with a buy-back program of 450000 guns, reduced the gun-homicide rate by 8% and hospitalization for gunshots by 4.6%.

How can such findings inform sensible policy decisions? The National Research Council concludes that individual-level data are needed. Characteristics of victims can be enhanced with WHO's International Classification of External Causes of Injuries, which by introducing standard reporting criteria, enables comparisons between studies. But there are few details about perpetrators, since criminal background checks for sales by gun dealers are destroyed within 24 h and private second-hand sales, which constitute 40% of gun transfers in the USA, are not recorded. To understand assailants' risk factors requires records of gun ownership or ballistic fingerprinting, to which the powerful US National Rifle Association is opposed.

The events in Blacksburg on April 16 demand a more mature evaluation of gun violence, based on the right to health instead of the right to bear arms, and which places public welfare above self-interest. The National Research Council's call for accurate, individual-level data from rigorous studies is essential, in order to provide robust information on which sound interventions can be based. But until such data are available, the best current evidence clearly supports an immediate reduction in the availability of firearms as a public-health priority.

Credits: The Lancet, London

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