The number of US movies in which an actor lights up Bond cigarettes fell sharply between 2005 and 2010, and this could have contributed to the decline in smoking among US teens, a study released Thursday says.

A majority of movies — 55 percent — that scored huge box office success in the United States in 2010 had no scenes that included tobacco use, compared with a third of top-grossing films in 2005, the study released by the Centers for Disease Control and Prevention (CDC) says.

In the same six-year period, the number of what are called “tobacco incidents” in top-grossing movies fell by 56 percent — but still clocked in at nearly 2,000 scenes where an actor used tobacco either openly, on screen, or implicitly, off-screen, the study says.

“The percentages of 2010 top-grossing movies with no tobacco incidents were the highest observed in two decades,” the CDC says in the study published in the Morbidity and Mortality Weekly Report.

“The decreased presence of onscreen smoking might have contributed to the decline in cigarette use among middle school and high school students,” it says.

A study released last year by the CDC found that the percentage of middle school students in the United States who smoked cigarettes fell from 11 percent to five percent between 2000 and 2009 and those who “experimented” with cigarettes fell from nearly 30 percent to 15 percent.

Use of other tobacco products, such as cigars, pipes and chewing tobacco, was also down among middle schoolers, generally aged between 11 and 14.

Among high school students, smoking was down, too, although less sharply, the 2010 study showed. Seventeen percent of high school students smoked cigarettes in 2009 compared with 28 percent in 2000, while three in 10 high schoolers tried smoking two years ago, compared with nearly four in 10 in 2000.

An analysis of four studies linked 44 percent of teens who started smoking with seeing tobacco products being used in movies, the CDC says in the study released Thursday. Most people start to smoke or use smokeless tobacco products when they are teens, the CDC adds.

With studies pointing to a link between less smoking on the silver screen and fewer teens taking up smoking, the US Department of Health and Human Services has made reducing youth exposure to onscreen smoking part of its 2010 strategic plan to cut tobacco use.

Three of the six major US movie companies have policies to reduce tobacco use in their movies, and the number of tobacco incidents in their G and PG movies fell from an average of 23.1 incidents per movie in 2005 to a single incident per movie last year, the study says.

“Tobacco incidents” were 10 times more frequent in movies made by independent companies and the three major studios that do not have anti-tobacco policies.

The study did not indicate which movie studios have anti-tobacco policies and which do not. Earlier this year, Paramount Pictures came under fire from the American Academy of Pediatrics (AAP) for its PG-rated animated feature “Rango,” which shows several characters using cigars and a cigarette.

“The hero, a chameleon, swallows a cigar and breathes fire in the face of a villain,” the AAP noted in March, shortly after the film was released.

“It is a mystery why Hollywood?s masters of storytelling and visual effects have not found a better way to depict their characters without the danger of influencing young people to light up.”