Phil Anderson
Kuldeep Bhatia
Joan Cunningham
This Occasional Paper is intended to make the results of current research available to other interested parties. The aim is to present accounts of developments and research work or analysis of an experimental nature as to encourage discussion and comment.
Views expressed in this paper are those of the author and do not necessarily represent those of the Australian Bureau of Statistics. Where quoted or used, they should be attributed to the author.
INTRODUCTION
The health disadvantages experienced by Australia's Indigenous people are well documented and occur throughout the life cycle, from babies of low birth weight, to greater illness and hospitalisation rates in children and adults, to early death from a variety of causes (see, for example, Bhatia and Anderson 1995). In order to assess the success of programs which have been implemented to address such problems, it is necessary to be able to identify changes in health status over time.
Several measures can be used to examine trends in health status, but for the Indigenous population this has largely been limited to mortality statistics because of a lack of suitable information of high quality for many other aspects of health and well-being. Death is an endpoint of importance because it is untreatable and irreversible. The legal requirements regarding notification of death mean that the fact that a death has occurred is generally very accurately recorded. The centralised nature of vital statistics reporting means that such information is relatively easy to collate and analyse. Even for death statistics, however, it is difficult to obtain a truly national picture because of incomplete identification of Indigenous people in the death records of some States. The identification of Indigenous people in the registration of deaths in Western Australia, South Australia and the Northern Territory has been of sufficiently good quality (Benham and Howe 1994) to allow the characterisation of Indigenous mortality in those jurisdictions. The information from these States and Territories has been combined to produce quasi-national mortality statistics, which form the basis of this report.
Death rates in Australia have shown a downward trend from the beginning of this century, and have almost halved since 1921 (d’Espaignet et al. 1991). Significant shifts in the age- and cause-specific patterns of mortality have occurred, due mainly to dramatic declines in infant mortality rates (by almost 90%) between 1921 and 1992. Deaths from infectious and parasitic diseases have become uncommon among non-Indigenous Australians, with lifestyle disorders now becoming the major contributors to death. Most deaths now occur in the later years of life.
The decline in death rates in Australia during the last three decades has been due largely to a reduction in deaths from cardiovascular diseases. Between 1981 and 1992, age-standardised death rates (ASDRs) in Australia for cardiovascular diseases declined at an average annual rate of 3.8% for males and 3.3% for females (Bennett et al. 1994). Deaths due to motor vehicle traffic accidents, pneumonia and influenza also declined between 1981 and 1992, although death rates for malignant neoplasms rose during this period (Bennett et al. 1994).
This report examines the mortality of Aboriginal and Torres Strait Islander people from 1985 to 1994. Death rates are examined in both absolute and relative terms. Absolute change is indicated in the presentation of trends over time. Change relative to the non-Indigenous population is measured through the use of standardised mortality ratios (SMR) in which the number of observed deaths is compared to those which would be expected based on non-Indigenous death rates. Both absolute and relative changes are important, but they measure different aspects of mortality. An increase in the SMR could, for example, occur because of an increase in the Indigenous death rate or because of a decrease in the non-Indigenous death rate. A falling death rate for the Indigenous population could signify improvement in absolute terms, yet if the decline were not as steep as for the non-Indigenous population, then there would be a worsening in relative terms.
It is worth noting that death rates may not be sensitive in the short term to some changes in health, especially subtle ones. Because the disease process leading to death can be long-term, there can be a delay in being able to see real progress (or regression). That is, changes for the better now may not result in falling death rates for some years to come because of already established chronic disease which will play itself out over time. Despite such limitations, however, mortality statistics continue to be an important source of information on the health of Indigenous Australians.
In addition to reporting trends in Indigenous mortality by sex and cause of death over the decade from 1985 to 1994, this publication presents an overview of Indigenous mortality in 1992-94, the most recent period for which data are currently available.
