The result? It took twice as much pepper extract to trigger coughs in children habitually exposed to secondhand smoke, compared with kids whose parents never smoked. A similar result held true for the children's parents, who also participated in the study, published in the current issue of Nicotine & Tobacco Research. That is, compared to nonsmokers, the smokers were less sensitive to the cough-inducing irritant.
Monell researcher Paul M. Wise acknowledged that the findings may seem counterintuitive, given the well-known phenomenon of smoker's hack. One might think that chronic smokers and their kids were more prone to coughing, not less.
The reality is that cigarette smoke desensitizes a person to airborne irritants and deadens the protective cough reflex, said Wise, who codirected the study with Monell colleague Julie A. Mennella.
"If your cough reflex is less sensitive, you'll be less able to clear the airways of accumulated secretions and bacteria and virus and chemical threats," Wise said.
In addition to its possible link with infection, this desensitization also may help explain why children of smokers are more likely to take up the habit, the study authors said. That's because, for such kids, experimenting with cigarettes may seem less unpleasant, the scientists reasoned.
The good part is that a smoker's cough reflex is known to recover within a few weeks of quitting cigarettes, and Wise supposese that the same would be true for their children.
- Tom Avril