New research suggests that television advertisements for e-cigarettes may be enticing current and even former tobacco smokers to reach for another cigarette.

Researchers from the University of Pennsylvania's Annenberg School for Communication found that people who smoke tobacco cigarettes daily and who watched e-cigarette advertisements with someone inhaling or holding an e-cigarette (aka vaping) showed a greater urge to smoke than regular smokers who did not see the vaping.

They also found that former smokers who watched e-cigarette advertisements with vaping had less confidence that they could refrain from smoking tobacco cigarettes than former smokers seeing e-cigarette ads without vaping.

"We know that exposure to smoking cues such as visual depictions of cigarettes, ashtrays, matches, lighters, and smoke heightens smokers' urge to smoke a cigarette, and decreases former smokers' confidence in their ability to refrain from smoking a cigarette," researcher Dr. Erin Maloney said in a statement. "Because many e-cigarette brands that have a budget to advertise on television are visually similar to tobacco cigarettes, we wanted to see if similar effects can be attributed to e-cigarette advertising."

For the study, researchers studied more than 800 daily, intermittent, and former smokers who watched e-cigarette advertising, and who then took a survey to determine smoking urges, intentions, and behaviors.

Researchers observed a trend that more daily smokers who viewed ads with vaping smoked a tobacco cigarette during the experiment than daily smokers who viewed ads without vaping and daily smokers who did not view ads. Over 35 percent of the daily smokers in the condition that showed vaping reported having a tobacco cigarette during the study versus 22 percent of daily smokers who saw ads without vaping, and about 23 percent of daily smokers who did not see any advertising.

"Given the sophistication of cigarette marketing in the past and the exponential increase in advertising dollars allotted to e-cigarette promotion in the past year, it should be expected that advertisements for these products created by big tobacco companies will maximize smoking cues in their advertisements, and if not regulated, individuals will be exposed to much more e-cigarette advertising on a daily basis," researchers wrote.

The findings are significant, considering that tobacco advertising on television went up in smoke over four decades ago by way of a federal ban. Moreover, e-cigarette advertising is stoked by big tobacco companies. Estimates peg e-cigarette ad spending at more than $1 billion this year. That number is expected to grow at a 50 percent rate over the next four years.

The findings are detailed in the journal Health Communication.