This is the finding of Tracking Disparity: Trends in Ethnic and Socio-economic Inequalities in Mortality, a report released by the Health Inequalities Research Programme.
Programme director and lead author of the report Professor Tony Blakely says this is good news for the health system.
"Previous research we've carried out using the New Zealand Census-Mortality Study shows quite clearly that health gaps relating to income and ethnicity widened markedly in the 1980s and 1990s.
But in 2001 to 2004 they have either narrowed or stayed the same."The report details two areas in particular: health disparities according to ethnicity and also socio-economic status.
The key findings are that death rates for all people, aged one to 74, fell across the whole period 1984 to 2004, and the death rates for Mäori and Pacific peoples also decreased, particularly in the late 1990s to 2004.
One of the main reasons for this is the fall in death rates from cardiovascular disease, with big improvements across Mäori, Pacific and European ethnic groups.
While the report found that heart disease still contributes more than 40 per cent of the gap in mortality rates for males, between Mäori and European/other, and 36 per cent for females, this has been falling over the last 25 years and the percentage contribution of cancer has been increasing.
The results are also positive with regard to socio-economic disparities and health; one- to 74-year-old death rates have also fallen for all income groups.
But Blakely says that, although this is a continuation of the good news, the concern is that low-income earners between 25 and 44 years have not experienced any real decline in mortality over the last 20 years.
"The message from this latest report is that there is probably a halting of the deterioration in health inequalities and an improvement in some areas in recent years," says Blakely.
"It also appears from this analysis that the underlying widening social inequalities in the 1980s and 1990s were partly responsible for increasing disparities in health outcomes."
Nevertheless, gaps in mortality are still very large.
The study shows two- to three-fold differences in death rates between Mäori and the European/other section of the population, and, while inequalities may not be widening, Blakely says there is still much to do to "close the gaps" in health disparities.
Blakely's data also clarify to what extent health disparities are caused by ethnicity or socio-economic factors.
The research suggests at least 50 per cent, and probably more, of the widening in Mäori:European/other mortality ratio among working adults is driven by socio-economic factors.
Whilst the report does not directly assess what explains ethnic gaps that are not due to socio-economic status, other factors such as racism, access to health care and lifestyle factors such as diet and tobacco are all likely to be important.
FUNDING
Health Research Council
Ministry of Health