A new study from the University of California, Berkley, has found that in the weeks following gun shows in Nevada, gun-related injuries and deaths in nearby California increased by nearly 70 percent.

The researchers looked at gun-related injuries and deaths in California before and after gun shows to see if there was a notable difference. They focused their research on anywhere within a convenient driving distance of a show that took place between 2005 and 2013, identifying 275 gun shows in nearby Nevada, mainly in Las Vegas and Reno, and 640 gun shows in California. 

Interestingly, their results, published in the journal Annals of Internal Medicine, found no increases in firearm-related deaths and injuries in California in the two weeks following a gun show, if the show was held in California. However, if the show was across the state line in Nevada, injury rates increased by 70 percent in nearby Californian communities.

Comparing the average number of deaths in the two weeks before and after a gun show, their results revealed the rate went from 0.67 per 100,000 people injured or killed by firearms to 1.14 per 100,000 following 161 Nevada gun shows. That's 30 more firearm-related deaths in California in the two-week period following a gun show in Nevada.

So why this difference? The authors suggest it's all down to the states' firearm regulations and background checks.

In California, the law requires background checks on all transfers of guns, including private transfers during gun shows. Nevada does not. In 2016 Nevada voters approved legislation requiring a background check on private sales, but it has not yet come into force.

By purchasing guns at gun shows, buyers from California are also bypassing the 10-day waiting period required in California after buying a firearm. A study that tracked purchases of firearms over a 45-year period recently found that a delay in receiving a handgun after purchase reduced homicides by 17 percent.

“The study suggests that travel to less-restrictive states may threaten the effectiveness of firearm laws within California," the study’s lead author, Ellicott Matthay said in a statement. "When a less-restrictive [state] is next to a state that is more restrictive, there may be spillover effects.”

 The researchers believe that nationwide the increase in injury and death could be larger.

“The area of California that borders Nevada is sparsely populated, and over the study period there were relatively few Nevada gun shows," Jennifer Ahern, the study's senior author said.

"However, there are thousands of gun shows in the United States each year, most of them in relatively unregulated states. If we extended this study nationwide, it is possible that the number of deaths and injuries associated with gun shows would be far greater.”