A U.K. study found that graphic warnings on cigarette packages had relatively little impact on deterring youth smokers. Reuters

For years health officials have tried to combat teen smoking with dire health warnings, but according to the findings of a new study, even graphic images on cigarette packages do little to deter teenagers from smoking.

Dr. Crawford Moodie, the lead researcher of a study published in the Tobacco Control journal, told the BBC that there is little statistical evidence to prove that the introduction of images like diseased lungs, gums and hearts on British cigarette packages in 2008 has had an effect on smokers. The study, conducted by Scotland’s Stirling University, surveyed 2,800 youths between the ages of 11 and 16, 10 percent of whom identified themselves as smokers.

While Moodie said the self-identified smokers were relatively unswayed by the graphics, he said the warnings did have an effect on non-smokers and children who had only experimented with smoking. Prior to the use of images, cigarette packs came only with text warnings.

The study concluded that while the portion of youths who believed that health warnings were an effective deterrent against smoking did increase after British cigarette manufacturers began including images in the labels, they have not proven any more effective than text warnings. According to data provided by the Youth Tobacco Policy Survey, the percentage of smokers deterred by health warnings held relatively constant, from 13 percent before the images began being used, to 14 percent, after.

The study also found that the images had significantly less of an impact when they were displayed on the back of a cigarette pack. "As warnings need to be salient to be effective, positioning pictorial warnings only on the less visible reverse panel limits their impact," the study's co-authors wrote. "While recall was high at both waves for pack-front (text) warnings, it was low -- below 10 percent -- for the pictorial warnings on the pack reverse, fear-appeal pictures aside."

Moodie said one hypothesis for why the picture warnings have not had the anticipated impact is that they haven’t been updated at all since 2008, suggesting that children may have become desensitized to them.

"Other countries regularly change their warnings,” Moodie said. “I think if we rotated them here they would have more impact."

Moodie said the study did have at least one “really positive” finding, a rise in non-smokers and casual experimenters.

Meanwhile, teen use of electronic cigarettes in the United States has risen dramatically in recent years, the Centers for Disease Control and Prevention reported on Thursday. According to research the CDC published this week in Morbidity and Mortality Weekly Report, the percentage of middle and high school students who have tried e-cigarettes more than doubled from 3.3 percent in 2011 to 6.8 percent in 2012.