Exposure to secondhand smoke decreases sensitivity to cough-eliciting respiratory irritants in otherwise healthy children and adolescents, according to a study.
The findings may help explain why children of smokers are more likely to develop pneumonia, bronchitis and other diseases and also are more likely to experiment with smoking during adolescence, researchers wrote in the journal Tobacco and Nicotine Research.
"Cough protects our lungs from potentially damaging environmental threats, such as chemicals and dust," Julie Mennella, PhD, a developmental biologist at the Monell Center and co-director of the study, said in a news release. "Living with a parent who smokes weakens this reflex, one of the most vital of the human body."
Adult smokers are known to have a less sensitive cough reflex relative to non-smokers, meaning that eliciting a cough in smokers requires more irritation. The Monell research team conducted the latest research to investigate whether the cough reflex of children and adolescents who regularly are exposed to secondhand smoke is affected in a similar fashion.
In the study, 38 healthy children ages 10 to 17 inhaled increasing concentrations of capsaicin from a nebulizer. Capsaicin is the burning ingredient in chili peppers and a potent chemical stimulus for cough. Seventeen of the youth regularly were exposed to smoke in the home, while 21 never were exposed to smoke at home. Parents also were tested.
The amount of capsaicin in the nebulizer was increased after each inhalation until the subject coughed twice. The capsaicin concentration that induced the two coughs was labeled as the individual’s cough threshold.
Youth regularly exposed to secondhand smoke required twice as much capsaicin to trigger cough compared with non-exposed children, meaning that the exposed children were less sensitive to the irritating environmental stimulus. A similar finding was true for the parents, confirming earlier findings.
The findings highlighted a previously unrecognized public health risk from exposure to secondhand smoke. An insensitive cough reflex could make exposed children less able to cope with environmental threats, which in could turn play a role in their increased risk for developing respiratory illness.
"This study suggests that even if an exposed child is not coughing, his or her respiratory health may still be affected by secondhand smoke," said Monell sensory scientist Paul Wise, PhD, a co-director of the study.
An insensitive cough reflex also could increase the adolescents’ risk of acquiring a smoking habit by making experimentation with smoking less unpleasant, the researchers hypothesized.
Future research will explore the relationships among secondhand smoke exposure, cough reflex and the sensory response to cigarettes to investigate whether exposure-related decreased sensitivity to irritants makes smoking more pleasurable to teens. The researchers also will seek funding to determine whether impairment of the cough reflex is reversible and how this may relate to the age when secondhand smoke exposure ceases.
The study abstract is available at http://ntr.oxfordjournals.org/content/early/2012/08/09/ntr.nts198.short?rss=1.
The findings may help explain why children of smokers are more likely to develop pneumonia, bronchitis and other diseases and also are more likely to experiment with smoking during adolescence, researchers wrote in the journal Tobacco and Nicotine Research.
"Cough protects our lungs from potentially damaging environmental threats, such as chemicals and dust," Julie Mennella, PhD, a developmental biologist at the Monell Center and co-director of the study, said in a news release. "Living with a parent who smokes weakens this reflex, one of the most vital of the human body."
Adult smokers are known to have a less sensitive cough reflex relative to non-smokers, meaning that eliciting a cough in smokers requires more irritation. The Monell research team conducted the latest research to investigate whether the cough reflex of children and adolescents who regularly are exposed to secondhand smoke is affected in a similar fashion.
In the study, 38 healthy children ages 10 to 17 inhaled increasing concentrations of capsaicin from a nebulizer. Capsaicin is the burning ingredient in chili peppers and a potent chemical stimulus for cough. Seventeen of the youth regularly were exposed to smoke in the home, while 21 never were exposed to smoke at home. Parents also were tested.
The amount of capsaicin in the nebulizer was increased after each inhalation until the subject coughed twice. The capsaicin concentration that induced the two coughs was labeled as the individual’s cough threshold.
Youth regularly exposed to secondhand smoke required twice as much capsaicin to trigger cough compared with non-exposed children, meaning that the exposed children were less sensitive to the irritating environmental stimulus. A similar finding was true for the parents, confirming earlier findings.
The findings highlighted a previously unrecognized public health risk from exposure to secondhand smoke. An insensitive cough reflex could make exposed children less able to cope with environmental threats, which in could turn play a role in their increased risk for developing respiratory illness.
"This study suggests that even if an exposed child is not coughing, his or her respiratory health may still be affected by secondhand smoke," said Monell sensory scientist Paul Wise, PhD, a co-director of the study.
An insensitive cough reflex also could increase the adolescents’ risk of acquiring a smoking habit by making experimentation with smoking less unpleasant, the researchers hypothesized.
Future research will explore the relationships among secondhand smoke exposure, cough reflex and the sensory response to cigarettes to investigate whether exposure-related decreased sensitivity to irritants makes smoking more pleasurable to teens. The researchers also will seek funding to determine whether impairment of the cough reflex is reversible and how this may relate to the age when secondhand smoke exposure ceases.
The study abstract is available at http://ntr.oxfordjournals.org/content/early/2012/08/09/ntr.nts198.short?rss=1.
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