Second-hand smoke traps teens

A Montreal researcher has found that exposure to second-hand smoke can make children more likely to become smokers when they are teenagers.

Dr. Margaret Becklake, professor in the departments of medicine and epidemiology, biostatistics and occupational health at McGill University, made the discovery during a study of school children in Montreal.

In the study, which was meant to look for asthma predictors, researchers studied 989 children in Grades One, 3 and 5 from 18 Montreal schools.

Between 1990 and 1993, they tested the cotinine levels - a measure of recent exposure to nicotine - in the saliva of 201 of these children to assess the levels of second-hand smoke they were exposed to at home.

These children were then restudied in 1994-1996, when they were roughly 11, 13 and 15 years old.

At that point, 83 of the 201 children examined identified themselves as “smokers” - defined as having smoked at least one cigarette a week for a month or more.

Becklake said the finding that cotinine levels from passive smoking in childhood can predict adult smoking came as a surprise.

Among the 201 children who had their cotinine measured in childhood, Becklake said salivary levels were higher (even when there were the same number of smokers in the home) in the children who took up smoking in their teens compared to those who did not.

“They appeared to get a bigger bang from their passive smoking,” said Becklake.

“If confirmed, this means the more second-hand smoke you absorb into your system as a child, the more likely you are to take up smoking later.”

Most smokers take up the habit before the age of 25, and according to Health Canada statistics, 85 per cent of the 250,000 Canadians who start smoking each year are under the age of 16.

Becklake said she intended to examine features of the home environment that favour the development of asthma in children.

But she was also interested in seeing whether there was anything her team of researchers could measure in primary school children which would predict which would become smokers in adolescence.

“We wanted to know if there were biological, as opposed to sociological, reasons for taking up smoking,” Becklake said.

“And it appears to be the case.”

The study also found that children who took up smoking had larger lungs than those who did not.

Becklake said she is baffled as to why these children had larger lungs.

She said the observation has been reported by others before, but there is no obvious explanation for it.

The study concluded in 1996 and researchers are now in the final stages of analyzing their data.

Becklake is currently looking to have the study published in a medical journal.

But she warned that the results are tentative until she can do further research to confirm the findings.

"These were entirely unexpected," she said.

“Of course, before we read too much into them, they must be validated in future studies and we are looking at ways to do so. But they do suggest fascinating and important links between the levels of smoke absorption from others and the formation of future smoking habits.”

Finding the funds to do further research is Becklake's next big challenge.

Her study was funded by the Inspiraplex federal Network of Centres of Excellence, one of the three networks that will lose their federal financial support at the end of March.

“Losing the federal network grant means further research may never get done,” said Dr. Peter Macklem, scientific director of the soon-defunct Inspiraplex respiratory health network.

“Industry is not going to support it because it's quality of life research that would have no economic benefit for them.”

Every four years, networks are considered for renewal. Three of the existing 14 networks were cut last fall to make room for new ones.

Inspiraplex, Concrete Canada and the Neurosciences Network were funded for eight years by the federal networks but lost their bid for renewal .

Inspiraplex received roughly $22 million dollars in federal funds over an eight-year period.

The network linked 70 respiratory health researchers in 18 universities and other research centres across Canada.

The NCE program gets $47.4 million a year from the federal government and the Natural Sciences and Engineering Research Council, the Medical Research Council, and the Social Sciences and Humanities Research Council -- councils which got a major funding boost in the budget last week.

“It's too bad Mr. Martin's money didn't come in time to reach projects like this one,” Becklake said.