"People don't want to confront an armed person at home, " said Garen J.

WSJ: Arizona gun proponents launch free gun program

"The Level I trauma centers are really expensive, " said Dr. Garen Wintemute, who works in UC Davis' Level I trauma center in California and is the director of its Violence Prevention Research Program.

CNN: Chicago's record murder rate: Don't blame guns alone

But Dr. Garen Wintemute, an emergency medicine physician and director of the Violence Prevention Research Program at the University of California, Davis, urged caution in interpreting the study in an accompanying editorial published in the journal.

CNN: Study links gun laws and lower gun mortality