NEW YORK: The fictional James Bond always had a license to kill, and research from New Zealand suggests the suave spy's movies have gotten more violent through the years.

“In fact, they got quite a bit more violent over time,” said Robert Hancox, senior author of a study published in the Archives of Pediatrics & Adolescent Medicine.

The concern is that children may watch these and other popular movies, and be exposed to an increasing amount of violence, said Hancox, who is at the University of Otago in Dunedin, New Zealand.

To test whether popular movies that are accessible and marketed to children and teens are showing more violent acts, Hancox and his colleagues analyzed the Bond movie series, which includes 23 films spanning the last 50 years.

The researchers watched each Bond movie and counted the number of violent acts, such as one character trying to shoot or punch someone else.

They found that the number of violent acts shown on the screen during the first Bond film in 1962,  “Dr. No”, and the film they analyzed in 2008, “Quantum of Solace”, more than doubled from 109 to 250, respectively.

The increase didn't come from trivial violence, such as a character slapping someone else, Hancox said.

“The change has been in the portrayal of severe violence,” he added, referring to any character punching, kicking or using a weapon.

Severe violence increased from 77 acts in the first film to 219 in 2008.

While the movies tended to show more violent acts over time, each movie had a different number of violent acts. For example, 1997's “Tomorrow Never Dies” contained about 400 violent acts, which is nearly twice as many as 1999's “The World is Not Enough.”

Metro-Goldwyn-Mayer Studios, which co-owns the copyright to Bond films with Eon Productions, had no comment on the research.

Amy Bleakley, a senior research scientist at the Annenberg Public Policy Center at the University of Pennsylvania, who was not involved in the study, told Reuters Health that the study results jibe with research she published earlier this year.

That study, which looked at top-grossing films between 1950 and 2006, she and her colleagues found movie characters were increasingly involved with violent acts.

“So when this content shows up in films kids are seeing, it can be problematic,” she said, adding that parents should follow the American Academy of Pediatrics recommendations, which suggest limiting screen time for movies, television, video games and the computer to one to two hours per day.

“The main point of this is that it's not just Bond,” said Hancox. “It's about what's happening in movies and media in general, and that they tend to be getting more violent.”