Having guns in the home triples the risk of suicide and doubles the risk of homicide, researchers reported on Monday.
Their review of 15 studies considered high quality confirms a clear association between gun ownership and violent death in the United States, where more than a third of the population owns firearms.
It's a touchy subject — gun rights activists say they suspect researchers want to restrict gun ownership. Congress has restricted federal funding of gun research, while President Barack Obama has explicitly instructed federal health agencies to start doing it again. Some groups, like the American Academy of Pediatrics, have also lobbied in favor of more research on gun violence.
Andrew Anglemyer and colleagues at the University of California, San Francisco, trolled through studies that had already been done to see if they could clarify the association between gun ownership and violent death. They found 14 studies that found the odds of suicide went up by anywhere from 1.5 times to 10-fold if people had access to guns. Experts say this is partly because guns are far deadlier than other suicide methods, such as taking pills, which may not succeed.
Studies looking at homicide found that if people had access to guns, they were two to three times more likely to be killed themselves.
"Firearms cause an estimated 31,000 deaths annually in the United States," they wrote in their report, published in the Annals of Internal Medicine. "Data from the 16-state National Violent Death Reporting System indicate that 51.8 percent of deaths from suicide in 2009 were firearm-related; among homicide victims, 66.5 percent were firearm-related."
Other evidence is even more overwhelming, David Hemenway of the Harvard School of Public Health wrote in an editorial also published in Annals.
"Why having a gun in the home would substantially increase the risk for being murdered by a person who is not a family member is uncertain, and Anglemyer and colleagues do not provide an explanation," Hemenway wrote.
"Obtaining a firearm not only endangers those living in the home but also imposes substantial costs on the community."