The number of children wounded or killed by gunshots has been climbing in recent years and states with high gun-ownership rates also tend to have lots of childhood firearm injuries, a new study shows.

While such a conclusion may seem obvious, epidemiological research in this field has been lacking because of pressure from some members of Congress to limit federally funded gun research for the past two decades.

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The new report out today by a Boston medical student and his advisor at Harvard Medical School provides some intriguing, and disturbing, trends. With nearly 7,500 children wounded and 500 killed each year, they found that the big problem is actually handguns.

“Our data shows that handguns are responsible for more hospitalizations and in-hospital deaths than any other firearm type,” said Arin Madenci, a surgical resident at Brigham and Women’s Hospital who conducted the study while a student at the University of Michigan School of Medicine. “While public health resources and policies have largely focused on military-style semi-automatic assault weapons, it may be more crucial to intervene on handguns.”

Madenci and Christopher Weldon, professor of surgery at the Harvard Medical School, compared household gun ownership and childhood gun violence across the 50 U.S. states. They used figures from the Behavioral Risk Factor Surveillance System, a database of personal health data maintained by the Centers for Disease Control in Atlanta since 1993.

Between 1997 and 2009, hospitalizations from gunshot wounds increased from 4,270 to 7,730, while in-hospital deaths rose from 317 to 503. The report is being presented today at the American Academy of Pediatrics conference in Orlando.

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“Based on our research, we know that there is a clear correlation between household gun ownership (and gun safety practices) and childhood gunshot wounds in the home on a large scale,” Madenci said in an email to Discovery News.

Madenci said he didn’t have enough data to determine whether guns in specific homes were responsible for these deaths or injuries, but said it is something they plan to answer in future studies. He said he decided to look at the question of gun ownership and childhood gun deaths after the shooting at Sandy Hook Elementary School in 2012. One expert says the study should not come as a big surprise.

“It’s consistent with general theory which is that greater exposure leads to greater risk,” said Daniel Webster, professor and director of the Johns Hopkins Center for Gun Policy and Research.

Webster said that Congress has eliminated federal funding for research into the causes of gun violence since the early 1990s under pressure from the National Rifle Association. President Obama used executive powers to restore funding after the Newtown shootings, and the National Institutes of Health has just released its first request for applications for studies in this field.

“I see this as a huge step forward,” Webster said.