Smoke-exposed kids show nicotine dependence signs

By Anne Harding

NEW YORK (Reuters Health) - Children who have never had a single puff of a cigarette may report symptoms of nicotine dependence if they've been exposed to secondhand tobacco smoke, Canadian researchers report.

"I think it's very compelling," co-investigator Dr. Jennifer O'Loughlin of the Universite de Montreal in Quebec told Reuters Health. "It's just one more link in the chain that parents shouldn't be smoking in front of their kids."

Previous research has shown that children exposed to environmental tobacco smoke at home or in the family car have nicotine and markers of nicotine metabolism in their urine, blood and hair, O'Loughlin and her team note in their report, published in the current issue of the journal Addictive Behaviors. One investigation showed that non-smoking children with higher concentrations of one of these markers, cotinine, in their saliva were more likely to become smokers 2 years later.

To further investigate the role of second-hand smoke exposure and nicotine dependence, O'Loughlin and her colleagues evaluated 1,488 children between 10 and 12 years old who had never smoked. At present, O'Loughlin noted in an interview, the best -- and only -- way to measure nicotine dependence is by symptoms, such as cigarette cravings and nicotine withdrawal.

Sixty-nine of the children, about 5 percent, reported at least one symptom of nicotine dependence. The most commonly reported symptoms included mental addiction, physical addiction, having a hard time not smoking when other people were, and feeling the need to have a cigarette.

The greater children's exposure to second-hand smoke at home or in motor vehicles, the more likely they were to exhibit these symptoms. Once the researchers adjusted the data by smoking susceptibility - how likely a child was to be influenced by the smoking behavior of their peers and family members -- the relationship remained.

This suggests, according to O'Loughlin's team, that the nicotine dependence symptoms children felt weren't solely due to social role modeling, but actually had a physiological basis.

The results, along with other recent findings showing that non-smoking adults exposed to second-hand smoke have nicotine withdrawal-like symptoms, "provide support for the hypothesis that second-hand smoke exposure in some youth may result in the development of psycho-behavioral symptoms believed until now to occur only among smokers," the researchers write.

"If replicated, these findings support public health interventions that promote non-smoking in the presence of children," the researchers conclude, "and, more specifically, uphold policy interventions to restrict smoking in motor vehicles in which children are present."

SOURCE: Addictive Behaviors, September 2008.