By Hope T. Jackson, MD

Cigarette ads may have been banned from television since 1971, but that hasn't stopped electronic cigarette makers from placing TV ads likely to be seen by children and young adults.

Researchers at Research Triangle Institute International found that between 2011 and 2013, e-cigarette TV advertisements that reached children increased by 256 percent, and those that reached young adults increased by 321 percent.

"TV is the primary way advertisers target youth, and these results aren't surprising given that e-cigarette brands have been purchased by tobacco companies, who've had major advertising budget increases," said study author Dr. Jennifer Duke. "It is very surprising that youth and young adult exposure is rising so rapidly."

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Duke and her team found that 80 percent of the ads were for the same company, Blu eCigs, and that the ads were airing on networks such as Comedy Central and VH1.

A woman is pictured purchasing an electronic cigarette on April 24, 2014 in Miami, Fla. (Credit: Joe Raedle/Getty Images)

E-cigarettes, battery-operated nicotine inhalers, have been met with controversy as researchers scramble to determine their health risks. The Food and Drug Administration announced earlier this year that it would begin regulating e-cigarettes.

"There are regulations currently in place to prevent youth-oriented flavorings in traditional cigarettes, but this regulation does not extend to e-cigarettes," said Dr. Brian Primack, a pediatrics professor at the University of Pittsburgh who was not involved in the study. "As a result, marketers see the potential value of targeting this product to them."

E-cigarettes are available in flavors like bubble gum and apple, and they come in a different colors.

The percentage of middle and high school students using e-cigarettes more than doubled between 2011 and 2012, according the Centers for Disease Control and Prevention. It's survey found that in one year, students using e-cigarettes went from 4.7 percent to 10 percent.

"Youth exposure to nicotine can cause changes in the developing brain that favor continued use of nicotine at later stages in life," Duke said.

The Smoke Free Alternatives Trade Association, an e-cigarette industry organization, told ABC News its members do not support or engage in advertising to minors. However, the group said too many restrictions on e-cigarette advertising may be "counterproductive" because "ads are an important source of information and education about the rapidly changing technology behind vapor products."

Blu Cigs sets limitations on advertising placement to be sure it's reaching audiences that are made up of at least 85 percent adults "in an effort to minimize any potential exposure to minors," according to a company statement sent to ABC News.

Doctor's Take

TV commercials expose us to hundreds of messages a day. This study provides evidence that advertisers target children at alarming rates, hoping not just for sales, but for brand loyalty in the future.

What may be even more alarming is that this study only looked at television advertising. Add in social media ads, radio and print, and kids and young adults are likely seeing e-cigarette ads frequently.

Research on the health risks of e-cigarettes continues, but nicotine in both traditional and e-cigarettes is highly addictive and has serious side effects.

Different flavors for electronic cigarettes are pictured for sale on Dec. 19, 2013 in New York City. (Credit: Spencer Platt/Getty Images)