Television ads that tobacco companies say are designed to discourage teenagers from smoking do no such thing, and some may actually encourage youths to smoke, researchers reported on Tuesday.

Their study of more than 100,000 U.S. teenagers shows that the ads may do more harm than good, the researchers report in the American Journal of Public Health.

“This study provides more proof that the tobacco industry is all smoke and mirrors,” said M. Cass Wheeler, chief executive officer of the American Heart Association.

“The tobacco industry is addicted to lying and in truth wants our kids to become addicted to tobacco. If they were serious about reducing smoking rates, they would stop spending $15 billion a year to promote their deadly products.”

Melanie Wakefield of the Cancer Council Victoria in Melbourne, Australia, and colleagues at the University of Illinois at Chicago and the University of Michigan got television viewing data from Nielsen Media Research.

They looked at the reach and frequency of tobacco company-sponsored ads and whether they were seen by 12-year-olds to 17-year-olds in the largest 75 U.S. media markets, covering close to 80 percent of all U.S. households, from 1999 to 2002.

They then looked at surveys of 8th, 10th and 12th graders in 48 states collected in the same period for a study on tobacco use and beliefs at the University of Michigan.

The data showed no correlation between frequency of the industry’s anti-smoking ads and actual or intended smoking by the teens.

“This research provides the clearest evidence to date that tobacco-sponsored ads don’t work,” Wakefield, also with the University of Illinois, said in a statement.

“Tobacco-sponsored ads targeted at youth have no impact and those targeted at parents seem to have an adverse effect on students who are in their middle and later teenage years.”

DELAYING BUT NOT PREVENTING

The researchers noted that cigarette giant Philip Morris launched a national $100 million television “Think. Don’t Smoke” campaign in December 1998.

“Lorillard Tobacco Company also launched a U.S.-televised youth smoking prevention campaign with the slogan, ‘Tobacco is Whacko if You’re a Teen,’” they added. Lorillard is owned by Loews Group.

They noted that in one tobacco trial, Carolyn Levy, a former director of Philip Morris youth smoking prevention programs, “admitted that the aim of their programs was to delay smoking until age 18” - not to prevent teens from ever smoking.

In the survey, teens living in markets where many parent-oriented ads aired were less likely to remember having seen such an ad, and were more likely to say they might smoke in the future.

“It is conceivable that tobacco company smoking prevention ads could have even greater adverse effects on youth smoking behavior than suggested by this study,” they wrote.

Peggy Roberts, a spokeswoman with Philip Morris, said the tobacco company does extensive research to ensure that its ads are effective with parents. “We haven’t found anything (in our research) to indicate that this study’s conclusions are valid,” she said.

Roberts said summer research showed that 61 percent of parents of kids from 10 to 17 years old were aware of at least one of the Philip Morris ads, and of those, a majority indicated that they had talked to their children about not smoking after seeing the ads.

Roberts also took issue with the comments attributed to Levy, saying such comments would have been inconsistent with the company’s goal. “I personally would have a hard time envisioning that she would have said such a thing,” Roberts said.