Has the prevalence of asthma symptoms increased in Australian children?

This paper estimates whether an increase has occurred in the prevalence of asthma symptoms and diagnosed asthma in Australian children over the past two decades. Seventeen population-based studies undertaken in Australia since 1969 were reviewed. Inclusion criteria were studies using population samples of children aged 5-12 years, with standardized questionnaire measurements. Data from serial National Health Surveys were also examined for trends in recent and chronic asthma. The prevalence of recent (12 month) and cumulative wheeze increased, showing a significant correlation with year of study (r = 0.78 and r = 0.79, respectively). Diagnosed asthma showed a smaller but still significant increase (r = 0.65). The trends observed indicated that diagnosed asthma and reported wheeze have increased by almost 1% per year over the past two decades. Data since 1980 have provided estimates of bronchial hyperreactivity (BHR), but no trend was observed. Substantial increases were noted in the National Health Surveys, with recent asthma prevalence in children aged 5-14 increasing from 3.3% in 1983 to 8.3% in 1989, and chronic asthma prevalence increasing from 4.5% in 1977 to 15.2% in 1989. The findings of this review suggest an increase in the prevalence of asthma symptoms in children, but these observations could also be explained by changes in diagnostic fashion and an increased awareness of asthma symptoms.