Despite declines in the number of youths who smoke cigarettes, hookah or water pipe use continues to rise among Canadian youth, a new study from the University of Waterloo reports. Published Monday in Cancer Causes and Control, the study found that almost one in four high school seniors try smoking hookah.

The study estimates that more than 78,200 youth are current water pipe users.

"While we can celebrate a continued slow decline in cigarette use across the country, water pipes are bucking the trend," said Leia Minaker, a scientist at the Propel Centre for Population Health Research at the University of Waterloo, who conducted the study funded by the Canadian Cancer Society.

Water pipes work by bubbling tobacco smoke through water, leading many users to believe that they carry less risk than cigarettes. The study, which analyzed data from the national 2012-2013 Youth Smoking Survey, found that over a third of youth believe it is less harmful to smoke tobacco in a water pipe than smoking a cigarette.

"The idea that water pipes are somehow less harmful than cigarettes is a dangerous misperception," said Minaker. "Since most water pipe smoking sessions last much longer than a cigarette, water pipe smokers may absorb higher concentrations of the same toxins as in cigarette smoke."

Water pipes join a growing number of products marketed to youth using flavoured tobacco. The survey found that among students who reported using water pipes, about half used flavoured products.

"The tobacco industry continues to add candy, fruit and other flavours to tobacco products to attract young people. Restricting flavours in tobacco products is an important part of a comprehensive tobacco control strategy," Minaker said.

Several countries have banned indoor water pipe smoking, including Lebanon, Turkey, and parts of Saudi Arabia and India, where water pipe smoking is a cultural activity. In Canada, Nova Scotia, Alberta and at least 12 municipalities have adopted legislation to prohibit any water pipe smoking in public places where smoking is banned.

The study also found that water pipe use increases significantly by grade, with boys more likely than girls to try hookah during their high school years. Youth with higher amounts of weekly spending money have significantly higher odds of using water pipes. About 14 per cent of grades 9 to 12 students in Canada have tried water pipes, up from 10 per cent in 2010.

"We want to be able to say with confidence that all kids in Canada can grow up tobacco free. One third of all cancers caused by tobacco use, and this type of tobacco use is growing among Canadian kids. Why wouldn't we put restrictions in place to protect youth from all types of tobacco use?" said Minaker.

The Canadian Cancer Society reports lung cancer as the leading cause of cancer death in Canada. It is estimated that 85 per cent of lung cancer cases are related to using tobacco products.

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