Exercise-induced bronchoconstriction by ethnicity and presence of asthma in British nine year olds.

BACKGROUND The prevalence of exercise-induced bronchoconstriction among British children by ethnicity has not been studied. METHODS Peak expiratory flow rate (PEFR) was measured before and after an exercise challenge test using a cycle ergometer in 593 nine year olds from Scottish and inner city English schools. Logistic regression analysis was carried out to assess the association between changes in PEFR with exercise by reported asthma, ethnicity, and sex. RESULTS The probability of exercise-induced bronchoconstriction was greater among the asthmatics than in either the children without asthma attacks or wheeze, or in the children with only wheeze (p < 0.01). Asian children were 3.6 times more likely to have exercise-induced bronchoconstriction than white inner city children, and also were more likely to have exercise-induced bronchoconstriction than those from the other ethnic groups (p < 0.01). CONCLUSION Exercise challenge can assess the prevalence of asthma in the community and detect under-reporting of asthma in ethnic minorities.