Causes of inequality in life expectancy between Indigenous and non-Indigenous people in the Northern Territory, 1981-2000: a decomposition analysis.

OBJECTIVE: To identify the causes of the gap in life expectancy between Indigenous and non-Indigenous populations of the Northern Territory and how the causes have evolved over time. DESIGN AND
SETTING: Analysis of NT death data over four 5-year periods, 1 January 1981 to 31 December 2000 inclusive. A decomposition method using discrete approximations (Vaupel and Romo) was applied to abridged life tables for the Indigenous and non-Indigenous populations of the NT. MAIN OUTCOME MEASURES: Contribution of causes of death, grouped according to global burden of disease groups and categories, to the life expectancy gap.
RESULTS: The gap between the life expectancy of Indigenous and non-Indigenous people in the NT did not appear to narrow over time, but there was a marked shift in the causes of the gap. In terms of disease groups, the contribution of communicable diseases, maternal, perinatal and nutritional conditions halved during the 20 years to 2000. Meanwhile, the contribution of non-communicable diseases and conditions increased markedly. The contribution of injuries remained static. In terms of disease categories, the contribution of infectious diseases, respiratory infections and respiratory diseases declined considerably; however, these gains were offset by significantly larger increases in the contribution of cardiovascular diseases and diabetes for Indigenous women and cardiovascular diseases, cancers and digestive diseases for Indigenous men.
CONCLUSIONS: The main contributors to the gap in life expectancy between the Indigenous and non-Indigenous populations were non-communicable diseases and conditions, which are more prevalent in ageing populations. With the life expectancy of Indigenous people in the NT expected to improve, it is important that public health initiatives remain focused on preventing and managing chronic diseases.