The Childhood Asthma Prevention Study (CAPS) is the first and only randomised controlled trial of the effectiveness of both house dust mite avoidance and modification of dietary intake of fatty acids, both implemented from birth, for the prevention of asthma and other allergic disease during childhood. The study started in 1997 and recruitment of 616 subjects was completed in January, 2000. The 3 year follow up showed encouraging early results, a small but significant decrease in respiratory symptoms and specific allergic sensitisation. Children in the CAPS cohort at 8 years are currently being followed up to examine the longer-term effectiveness of the interventions using skin prick tests, airway hyperresponsiveness (AHR) spirometry and genetic studies.

An NHMRC project grants has also been awarded to the research group to investigate sex-related changes in asthma during the transition through puberty in the CAPS birth cohort.  Early adolescence is a critical period in the life of people with asthma. Some children "grow out" of their asthma and others acquire the disease for the first time. There are important sex differences in the pattern of change. We believe these changes are related to the passage through puberty. This study will examine changes in the features of asthma and allergy during this period and their relation to early life and current environmental exposures.  We will follow-up a high risk cohort for asthma that was recruited antenatally between 1997 and 2000. During their first five years of life, the children were participants in a randomised controlled trial of two interventions, house dust mite avoidance and modification of dietary fatty acids, to prevent the onset of asthma. The members of cohort were last assessed at age eight years. In the study proposed here, we will obtain data on growth in height at three monthly intervals and self-reported stages of puberty, including age at menarche (in girls) and the development of secondary sexual characteristics, at yearly intervals from age 11 years. At ages 11 ½ and 14 years, we will undertake detailed assessments of environmental exposures, pubertal stage (including sex-hormone levels) and respiratory and allergic outcomes. This cohort analysis will allow us to examine the relation among early and current environmental exposures, stages of puberty and sex-specific changes in the course of asthma during early-to-mid adolescence.