Asthma is more prevalent in Australia than in Europe or North America. As part of the European Community Respiratory Health Survey (ECRHS), we investigated exposure to risk factors for
asthma among young adults in Melbourne. During this study, 553 randomly selected and 204 symptomatic participants aged between 20 and 44 years completed a detailed respiratory questionnaire, of whom 675 underwent measurement of
bronchial hyperreactivity (BHR) by
methacholine challenge and 745 had skin prick tests for atopy. Current
asthma, defined as BHR and wheeze in the preceding 12 months, was present in 25.5% of those tested. A family history of
asthma was a risk factor for current
asthma (maternal
asthma odds ratio [OR] 2.4, paternal
asthma OR 2.1). Current smokers were 1.7 times more likely to have current
asthma. A serious respiratory
infection before 5 years of age increased the risk of current
asthma 2.3-fold. Atopy on skin testing was also strongly associated with current
asthma (OR 5.9). The greatest risks were associated with positive skin tests to Cladosporium, house dust mite, cat and rye grass pollen. We conclude that female gender, maternal
asthma, smoking,
hayfever, early respiratory
infection, occupational exposure and atopy are important risk factors for
asthma in young adults.