Asthma and atopy in four rural Australian Aboriginal communities

OBJECTIVE: To determine the prevalence and nature of asthma in four rural Australian Aboriginal communities. DESIGN: Cross-sectional population study. SETTING: Four Aboriginal communities in Queensland, the Northern Territory and South Australia, Australia. SUBJECTS: Data were collected from 1252 subjects aged 5-84 years in August 1990 and August/September 1991. MAIN OUTCOME MEASURES: Respiratory symptoms, measured by interview-administered questionnaire; airway hyperresponsiveness (AHR), measured by histamine challenge; and allergy, measured by skin-pick tests. AHR was a PD20FEV1 of histamine of less than or equal to 3.9 mumol. RESULTS: The prevalence of AHR in the four communities ranged from 2.2% to 7.5% and significantly increased with age (chi 2 trend test: P < 0.05). The prevalence of current asthma was 0.5% among 8-12 year old children and 3.3% among adults. The overall prevalence of atopy in the four communities ranged from 21% to 34%. Allergy to cats, house dust mites or cigarette smoking was a risk factor for AHR, and cat allergy was a risk factor for current asthma. CONCLUSIONS: The prevalence of asthma in rural Aboriginal adults is low in comparison with the prevalence among non-Aboriginal Australians, and asthma in Aboriginal children is almost non-existent. The low prevalence of asthma is possibly due to environmental factors that influence the acquisition of atopy and AHR.