Parents who smoke may weaken their child’s cough reflex, according to a study by US scientists. The study shows another effect of passive smoking on children’s health.
Despite the widespread perception by doctors that there is a natural tendency for children to cough more in smoky homes, a new study, published in Oxford Journal’s Nicotine & Tobacco Research, found the exact opposite.
The cough reflex is a natural defense against potentially harmful particles that enter the respiratory tract. The cough serves to keep them open and protects the lungs from irritating chemicals, food, bacteria and smoke.
Previous studies have shown that smokers have an impaired cough reflex and therefore a higher coughing threshold, meaning that smokers begin to cough when more irritants enter their airways. Philadelphia researchers tried to see if the same principle applied to children.
Paul Wise, a psychologist at the Monell Chemical Senses Center in Philadelphia, and his colleagues examined 38 healthy children between the ages of 10 and 17, half of whom came from a smoking home and the other had not been exposed to cigarette smoke.
The children were asked to inhale an irritating chemical – capsaicin – the burning ingredient in chillies. Scientists gave the gas in increasing concentrations, and when the child coughed twice, this was considered the cough threshold.
The researchers found that children who came from homes where their parents smoked at least 10 cigarettes a day required twice as much capsaicin as other children before reaching their coughing threshold.
This study is the first to show that passive smoke exposure actually reduces a child’s cough response, said Dr. Fernando Urrego, head of pediatric pulmonology at the OCHSNER Health Center in New Orleans.
A child’s innate airway defenses are not working, Urrego said, children who breathe in smoke are more likely to catch colds and have a higher risk of contracting pneumonia because they cannot clear the secretions from their lower respiratory tract.
This study may also point to one of the reasons why children who smoke are more likely to smoke in the future. They do not feel as intensely the unpleasant throat irritation from cigarette smoke as people growing up in non-smoking homes. (PAP)
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