MONDAY, Jan. 17 (HealthDay News) -- Tobacco advertisements really do prompt teenagers to smoke, say the authors of a new study that calls for a ban on cigarette ads.

In research involving more than 2,100 public school students in Germany, 277 young people who had never smoked before took up the habit after viewing tobacco advertising. Those who saw the most ads were 46 percent more likely to try cigarettes than those who saw no tobacco ads, the study found.

This "just adds weight to the idea of having the [U.S. Food and Drug Administration] be able to control tobacco marketing," said study co-author Dr. James D. Sargent, a professor of pediatrics and family and community medicine at Dartmouth Medical Center in New Hampshire.

Sargent, who has done extensive research on the influence of media on teen behaviors, worked with German researchers to produce the study, published online Jan. 17 in advance of print publication in the February issue of Pediatrics.

"There is a mental model for how advertising works," said Sargent. After viewing an ad, teens "start having favorable thoughts about smoking: 'it might be fun, it might make me more socially accepted.' This preceded any intent to smoke on their part."

Eventually a teen who has seen tobacco ads thinks about trying smoking, and soon after that "they try it," said Sargent.

Students involved in the study ranged from 10 to 17 years old, with an average age of 12.5 years, when the study began. They were shown 12 ads with branding removed -- six for cigarettes and six for other products, including candy, cars and cell phones. They were asked to identify the product advertised and recall the brand if they could.

After nine months, 13 percent of the students who had seen tobacco ads began smoking, showing a strong connection between the behavior and tobacco advertising, said Sargent. And the more ads they saw, the more likely they were to start smoking, the study found.

Smoking was not related to advertising for other products, the researchers said.

"Each one of these studies that we do is another little block that supports causality, just another little piece of evidence," Sargent said.

Other known risk factors for teen smoking, such as parental and peer smoking, were controlled for during the data analysis, the researchers said.

"This [study] is very important because there are few, if any, longitudinal studies," demonstrating a link between tobacco advertising and teen smoking, said Cheryl Healton, president and CEO of the American Legacy Foundation, an anti-smoking organization.

Previous research has mostly relied on cross-sectional studies, she said. That type of study documents incidence of a behavior at a certain point in time and may suggest a link between, say, smoking and advertising, but it doesn't show cause-and-effect. A longitudinal study, on the other hand, follows participants for a period of time in an effort to demonstrate that one causes the other.

Advertising exploits themes that are meaningful to teens including sex appeal, masculinity for boys, thinness for girls, and social acceptance, according to research cited in the study. Most smoking starts during adolescence, and because tobacco is a powerful psychoactive drug, the path to addiction readily follows, the authors added.

Healton said tobacco companies spend about $30 million a day on advertising in the United States alone. They "have to get young people to smoke or else they will go out of business," she said.

Although tobacco advertising is banned on American television, Healton said some TV programs promote smoking by showing characters lighting up.

" Sex and the City was the longest-running ad for Marlboro Lights," she said, referring to the popular TV series.

In the United States, teen smoking has declined dramatically since its peak in 1997, according to data provided by Legacy. Yet, in 2007 about 20 percent of American teenagers reported smoking in the previous 30 days, the American Lung Association reported.

More information

The Nemours Foundation details the dangers of smoking for young people.