By Michelle Roberts
20 September 2011 Last updated at 03:17
Teenagers who watch films showing actors smoking are more likely to take it up, new UK research suggests.
Experts who made the link by questioning 5,000 15-year-olds say their findings should prompt a change in film certification so that under-18s are no longer exposed to such images.
The Bristol University investigators say a precautionary approach is needed.
But pro-smoking choice campaigners say this is unjustified and nonsensical.
They say there is no proof that what a person views at the cinema or on DVD influences their decision about whether or not to smoke.
The latest research, published in the journal Thorax, looked at the potential influence of some of the 360 top US box office films released between 2001 and 2005, including movies like Spider-Man, Bridget Jones and The Matrix, that depict smoking.
Adolescents who saw the most films depicting smoking were 73% more likely to have tried a cigarette than those exposed to the least. And they were 50% more likely to be a current smoker.
Knowing that smoking attitudes are influenced by factors such as whether an individual’s parents and peers smoke, the researchers also gathered data about the adolescents’ social background.
Even after controlling for these variables, these teenagers were still 32% more likely to have tried a cigarette themselves, they said.
Dr Andrea Waylen, who led the research, said: “We saw a linear relationship between adolescent smoking and the number of films they had seen depicting smoking.
“More than half of the films shown in the UK that contain smoking are rated UK15 or below, so children and young teenagers are clearly exposed.”
She said raising certification to 18 was necessary in the UK and would lower youth smoking rates.
The UK Centre for Tobacco Control Studies has written to the British Board of Film Classification (BBFC) asking it to do just this to protect children from “particularly harmful imagery”.
Both U (universal) and PG (parental guidance) film ratings proscribe “potentially dangerous behaviour which young children are likely to copy”. This includes drug misuse but not cigarette smoking.
David Cooke, director of the BBFC, said: “Smoking is a major public health issue and we consulted the public very extensively on it in 2005 and 2009. Their clear expectation is that we should be vigilant, sensible and proportionate in how we deal with the issue.
“Glamorising smoking has therefore been included as a classification issue in our published classification guidelines and we frequently use our extended classification information to draw the attention of parents and others to depictions of smoking in films.
“There is, however, no public support for automatically classifying, for instance, a PG film at 18 just because it happens to contain a scene of smoking. We always look carefully at all research on this and related subjects drawn to our attention.
“Experience suggests, with media effects research generally, that attempts to claim a causal link between a particular depiction and a particular behaviour are often disputed and seldom conclusive.”
Simon Clark, director of the smokers’ group Forest, said: “The idea that films need to be reclassified in order to create a utopian, smoke-free world for older children is not only patronising, it is completely unnecessary.
“Today you would be hard-pressed to find a leading character who smokes in any top 10 box office movie.
“What next? Should government reclassify films that feature fat people as well in case they are bad role models?
“We go to the cinema to escape from the nanny state. The tobacco control industry should butt out and take its authoritarian agenda elsewhere.”