Maryland Attorney General J. Joseph Curran Jr. and his counterparts across the nation are asking Hollywood's major studios to couple any depictions of smoking in movies with anti-smoking ads on the recordings they release.

Curran (D), who has led the charge for many years, collected signatures from 31 other attorneys general, from Hawaii to Maine, for letters he sent to nine major studios last month.

The letters are the latest effort by the top law enforcement officials, who in past years have flown to Los Angeles to meet with directors and studio heads, testified before Congress, pressured theater owners and brought researchers before the Motion Picture Association of America.

Their efforts were boosted this month by a Dartmouth Medical School study showing that teenagers who watch movies depicting smoking are more likely to try it.

The study also prompted a letter from the National Parent Teacher Association, American Academy of Pediatrics, American Heart Association and American Medical Association.

"The Dartmouth study is a big deal," Curran said. "It documents the problem. It's proof."

The study, funded by the National Cancer Institute and published in the Nov. 7 issue of Pediatrics, surveyed 6,522 children ages 10 to 14 and found that one-third who began smoking did so because of exposure to it through movies.

Among the study's suggestions were the anti-smoking previews.

The American Legacy Foundation, a nonprofit organization established as part of a 1999 tobacco industry settlement, has begun talks with theater owners to put such public service announcements in theaters.

In his letter, Curran suggests putting ads produced by American Legacy on DVDs.

American Legacy has scripts for five ads but has yet to film them, said President Cheryl G. Healton.

"The issue is extraordinarily complicated politically," she said. "There's just an apparent lack of interest in the industry. We'll just keep pushing on multiple fronts and hope for a breakthrough somewhere."

The debate over smoking in movies has gathered momentum since the 1990s as the strategy of anti-smoking advocates has evolved to match counterarguments from the movie industry, said Stanton A. Glantz, director of the Center for Tobacco Control Research and Education at the University of California at San Francisco.

"If you look at the first 10 years, we were trying to work with Hollywood to reduce the actual appearances of smoking," Glantz said. "We'd go to these meetings. The studios would listen, wring their hands, say how much they hate smoking but couldn't interfere with artistic freedom."

So in recent years, to sidestep the artistic freedom argument, anti-smoking advocates have begun focusing on such efforts as Curran's push for anti-smoking ads and a move to account for smoking scenes in the MPAA's rating system.

Last month, in response to Curran's letters, MPAA spokeswoman Kori Bernards said each studio would have to decide individually whether to include anti-smoking ads. Many studios did not return calls by The Post to comment, and one reached, MGM, declined to comment.

As for changing the rating system so teenagers would see less smoking, Bernards said: "The rating system we have now has an 80 percent approval rating among people. I challenge you to find anyone with an 80 percent approval rating right now in this country."

Late last month, Curran's office said it had not received a response from studios on its letters.

"The movie people, to be fair about it, have listened to us," Curran said. "We just have to keep bringing it to their attention. It's a strictly voluntary effort; there's nothing we can do to force it on them."

Still, he said he and other attorneys general are not likely to give up on the issue.

"If we knew a way to prevent other diseases like heart attacks or diabetes, we'd do it in a heartbeat," he said. "Well, we know how to prevent smoking. So let's do that."