The researchers said the increase -- which comes just a year after the U.S. Surgeon General warned that watching movies with smoking scenes causes youngsters to start smoking -- is a setback for national youth tobacco prevention goals.
The report found that half of youth-rated movies in 2012 delivered an estimated 14.8 billion "tobacco impressions" to audiences, a 169 percent increase from the historic low in 2010. Tobacco impressions are depictions of tobacco use multiplied by the number of tickets sold per film.
The study was funded by Legacy, a nonprofit, antismoking foundation based in Washington, D.C.
"Movies may be more powerful than traditional tobacco ads," Cheryl Healton, president and CEO of Legacy, said in a foundation news release. "We know that the more smoking that youth see in movies, the more likely they are to smoke. This explosion in on-screen smoking puts hundreds of thousands of young Americans at risk of addiction, disease and premature death."
The report noted that three major film studios had eliminated almost all smoking in their youth-rated movies in 2010. But by 2012, one of the companies -- Time Warner's Warner Bros. -- had the most depictions of smoking in their youth-rated movies, followed by Sony and News Corp.'s 20th Century Fox.
"Increases in smoking imagery in the movies are discouraging," Dr. Tom Frieden, director of the U.S. Centers for Disease Control and Prevention, said in the news release. "Every day in the United States approximately 3,800 youth under 18 smoke their first cigarette, and approximately 1,000 become daily cigarette smokers. Reducing smoking and tobacco use in youth-oriented movies will help save lives, money, and years of suffering from completely preventable smoking-related chronic diseases."
Since 2002, the CDC has listed on-screen smoking as a factor in young people taking up smoking. Research suggests that seeing smoking in movies is a factor in 37 percent of new young smokers in the United States taking up the habit, according to Legacy.
About 800,000 current smokers in the United States are aged 12 to 17, the release noted. Of those, up to 250,000 will eventually die from tobacco-related diseases and may incur medical costs of $18 billion up to age 50.
The Nemours Foundation has more about youngsters and smoking.