article_snippet.sent: Researchers examined data from two nationally representative surveys of primary and secondary schoolchildren from more than 150 schools across Wales.
article_snippet.sent: Professor Peter Hajek, director of the Tobacco Dependence Research Unit, at Queen Mary University of London, said: 'The results of this large survey tally with all other available data and the picture is consistently reassuring. '
article_snippet.sent: The Cardiff University study was published in BMJ Open.