Ten- to 14-year-olds are about two times more likely to start smoking when they see movie characters smoking — regardless is the character is a "good guy" or "bad guy," a new study indicates.

"Episode for episode, there is a greater likelihood of an adolescent starting to smoke if she or he sees a 'bad guy' smoking," Dr. Susanne E. Tanski, of Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire, told Reuters Health.

However, she and colleagues identified about five times fewer "bad" than "good" characters among the 3848 major movie characters they assessed. Therefore, "the net effect of both 'bad guy' and 'good guy' smoking is about the same," Tanski said.

Adolescents with low sensation-seeking tendencies — in other words at low risk for taking up cigarette smoking — seem more influenced by "bad guy" smoking, Tanski and colleagues found.

The investigators surveyed movie watching among 6522 boys and girls representative of the 10- to 14-year-old population in the U.S.

In 532 movies most commonly watched, the researchers deemed nearly 65 percent of the characters as "good" and just over 13 percent as "bad," based upon how characters were portrayed. Of these, 14 percent "good" and 23 percent "bad" characters smoked.

Over the course of 2 years, 16 percent of the adolescents started smoking. Exposures to the smoking characters increased the odds of trying smoking by about twofold, even after accounting for known smoking risk factors such as older age, poor school performance, having a parent, sibling or friend who smoked, and being a sensation-seeker.

Tanski noted that previous investigations have shown that the association between adolescent smoking and exposure to smoking in movies "is strong."

"This study specifies that it does not matter if the smoking is by a positive or negative character," Tanski said.