Teens ages 12 to 17 were exposed to many new e-cigarette television ads between 2011 and 2013, a new study finds. Young people in this age group experienced a 256 percent jump in exposure to the ads during those years, according to NBC News.

Young adults, ages 18 to 24, experienced a 321 percent increase in e-cigarette ad exposure between 2011 and 2013, researchers from RTI International wrote in the journal Pediatrics.

More than 80 percent of the ads in 2013 were for a single brand, blu eCigs, owned by the tobacco company Lorillard. More than three-quarters of the ads aired on networks known to be popular with young people, including Comedy Central, TV Land, WGN America, VH1, Country Music Television and AMC.

“If the current trends continue, awareness and use of e-cigarettes will increase among youth and young adults,” study co-author Jennifer Duke, PhD, said in a news release. “And unfortunately, in the absence of evidence-based public health messages regarding the health risks of e-cigarettes, television advertising is promoting beliefs and behaviors that pose harm to youth and young adults and raise public health concerns.”

“This whole study is tremendously concerning to me,” pediatrician Dr. Deb Lonzer of Cleveland Clinic Children’s told NBC News. “Celebrities have enormous power and they are touting the benefits of smoking. I’m just a nerdy little pediatrician, how can I compete with some celebrity or the deep pockets of a tobacco company?”