Asthma in the Australian Indigenous population: a review of the evidence.
BACKGROUND
In 2001 national health survey data, Indigenous Australians reported asthma as the second most commonly experienced health condition. This systematic review was undertaken to determine the current evidence concerning asthma in the Aboriginal and Torres Strait Islander population.


METHODS
The review was conducted according to Australian National Health and Medical Research Council guidelines. Relevant databases and Internet sites were searched with selection criteria inclusive of all study designs, outcome measures and interventions that investigated asthma in Australian Indigenous participants. Studies of Level 4 evidence were graded using the READER critical appraisal tool, in the absence of an instrument validated and specifically designed for the Indigenous Australian context.


RESULTS
A total of 10 descriptive studies published in scientific journals were found, which were largely cross-sectional prevalence studies with rural and remote populations and retrospective reviews of hospitalisation data. There are no published scientific papers on the prevalence of asthma in Indigenous individuals dwelling in metropolitan areas. Other papers included a review, an editorial, and a number of abstracts and letters. Three national health surveys published by the Australian Bureau of Statistics were included. Inconsistency of results regarding the prevalence of asthma was common among studies. Asthma prevalence in rural children has been described as low as 0.5% and as high as 39.4%, and in rural adults in one study as 3.3%. In remote communities, asthma prevalence has been described as 15.8% for children, and for adults between 7% and 26%. National health survey data in the last 10 years has described overall prevalence of asthma in the Indigenous population in the range 15.3%-19%. Hospitalisation data for children with asthma in the Northern Territory showed that rural Indigenous children were admitted significantly less than urban non-Indigenous children, while a Western Australian study found that admissions for asthma were 3.1 times higher in Indigenous than non-Indigenous children, and rates were higher in non-metropolitan compared with metropolitan areas. A single descriptive study of an asthma management strategy utilised with good attendance rates on a remote Torres Strait Island has been published. It is unclear whether the divergence in research findings reflects a difference in prevalence of asthma across demographic regions and among different states and territories, or results from the lack of standardisation of epidemiological research methods used.


CONCLUSIONS
Previous research efforts concerning asthma in the Australian Indigenous population are insufficient, although there has been an increasing number of studies published during the past decade. All studies undertaken reside at a low level on the hierarchy of evidence scale. There remains no consensus of scientific opinion around the prevalence and aetiology of asthma in Aboriginal and Torres Strait Islander individuals. Particularly lacking are quality studies on asthma management interventions. Extensive consultation with Indigenous communities is indicated in order to determine priorities for asthma research. Following this, well-funded studies of a high methodological quality and culturally appropriate design investigating asthma in the Indigenous population should be undertaken.
Dawson
A P
AP
Division of Health Science, City East Campus, University of South Australia, Adelaide, South Australia, Australia. anna.dawson@unisa.edu.au