Mortality trends in Australian Aboriginal peoples and New Zealand Māori

Bronwen Phillips, John Daniels, Alistair Woodward, Tony Blakely, Richard Taylor, Stephen Morrell

The health status of Indigenous populations of Australia and New Zealand (NZ) Māori manifests as life expectancies substantially lower than the total population. Accurate assessment of time trends in mortality and life expectancy allows evaluation of progress in reduction of health inequalities compared to the national or non-Indigenous population. Age-specific mortality and life expectancy (at birth) (LE) for Indigenous populations (Australia from 1990 and NZ from 1950); and all Australia and non-Māori NZ (from 1890), males (M) and females (F), were obtained from published sources and national statistical agency reports. Period trends were assessed for credible estimates of Indigenous LE, and the LE gap compared to the total population for Australia, and non-Māori for NZ. Period trends in premature adult mortality, as cumulative probability of dying over 15-59 years, were assessed similarly. The relative contribution of differences in age-specific mortality to the LE gap between Indigenous and the all-Australia population, and the non-Māori NZ, was estimated for each country by sex for the most recent period: 2010-2012 for Australia, 2012-2014 for NZ. LE increased for all populations, although LE gaps between Indigenous and all Australia showed little change over time. LE gaps between NZ Māori and non-Māori increased significantly from the early 1980s to the mid-1990s, and since then have fallen again. Recent LE gaps in Australia (M 12.5; F 12.0 years in 2010-2012) were larger than in NZ (M 7.3; F 6.8 years in 2012-2014). Premature adult mortality (15-59 years) improved for all populations, but mortality ratios show little change since 2000, with Indigenous at 3½-4 times that of all Australians, and Māori 2-3 times that of non-Māori. Using decomposition analysis, the age interval contributing most strongly to differences in LE between Indigenous and all Australia was 35-59 years, but between Māori and non-Māori it was 60-74 years. In Australia and NZ, Indigenous LE and adult mortality are improving in absolute terms, but not relative to the entire or non-Indigenous populations, causing gaps in life expectancy to persist.