Laughter is major asthma trigger

Laughter is more likely to trigger an asthma attack in a child than exercise or smog, according to an Australian study.

Richard Henry and colleagues at the University of New South Wales analysed all cases over a six-month period of children who were taken to the emergency department at Sydney Children's Hospital because they were suffering from an asthma attack. Almost one third had what Henry calls "mirth-triggered asthma".

"This is one example where laughter is not the best medicine," Henry told delegates to a meeting of the Thoracic Society of Australia and New Zealand in Cairns. "We like our children to be happy but if children with asthma can't be happy because it brings on asthma, that's a major potential problem."

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The parents of these children, as well as children with asthma who attended outpatient respiratory clinics at the hospital, were asked to complete questionnaires on symptoms, medication and triggers.

Mirth-triggered asthma was more common in older children, in those with more night-time and early morning symptoms, and in those who reported changes in weather and chemical irritants as also being triggers for attacks.

The reasons for the link are unclear, but Henry thinks mirth-triggered asthma is primarily caused by the physical stimulation of irritant receptors in the airways. However, he says that laughter-triggered problems can be avoided if the asthma is managed properly.

Henry's team also asked the parents of 62 children with asthma to keep laughter diaries, and to measure their child's "peak expiratory flow" after each asthma attack. Laughter while watching a film caused the biggest reduction in flow.

Emma Young