Exercise-induced wheezing risk increases with asthma severity

By Sara Freeman, medwireNews Reporter

Exercise-induced wheezing (EIW) is associated with the severity of asthma, according to the findings of a large, cross-sectional survey conducted in Japanese children.

Children who had an asthma attack every day were 24 times more likely to have EIW at least once a week than those who had no asthma attacks in the preceding 4 weeks.

The risk of EIW was four to six times higher when compared with children with intermittent asthma attacks.

“It is concluded that EIW was not rare among current asthmatic children, and the increasing severity of current asthma was associated with the heightened risk of having EIW”, say Satoshi Honjo, from the Fukuoka National Hospital, and colleagues in Allergology International.

Honjo et al analysed data on more than 184,000 children recruited from 1931 educational institutions to participate in a national survey of asthma and other allergic diseases conducted across Japan in 2008.

Children were recruited from nurseries, primary schools, junior high schools and high schools and they, or their parents, completed the International Study of Asthma and Allergies in Childhood questionnaire.

The prevalence of EIW was found to be 4.8% among nursery-aged (3–6 years) children, 4.7% among those attending primary schools (6–8 years), 17.9% among those at junior high schools (13–15 years) and 15.4% among those attending high schools (16–18 years).

Of 24,103 children identified as having current asthma, the prevalence of EIW was 20.9%, 28.7%, 76.1% and 73.6%, respectively. The prevalence of EIW in children without current asthma in each of the four educational groups was 0.8%, 0.7%, 11.6% and 10.0%.

Odds ratios for having EIW due to having current asthma were 35.16, 53.63, 24.42 and 25.20, respectively.

The researchers suggest that given the “strong and consistent” link between current asthma severity and EIW, a higher EIW frequency could signify a higher frequency of an asthma attack in general.

Since some children without current asthma reported EIW, particularly among the children aged 13 years and older, they reasoned that some children did not consider EIW to be an asthma attack.

“When seeing patients in this age range with suspected asthma, possible presence of EIW should be asked”, Honjo and team advise. While better asthma control may improve EIW that could limit school activities, better control of EIW might also initiate better asthma control, they suggest.

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