Socio-economic status (based on factors like income, occupation and education) is a key determinant of health. People living in favourable circumstances continue to experience better health than people living in poverty, within a context of rising living standards, improvements in life expectancy, changing causes of illness and death, and developments in medical technology since the 19th century. Health inequalities between rich and poor are found in every area and for almost all diseases.
Researchers have argued about how socio-economic factors affect health, but accept that there is a connection. It is likely that a combination of material poverty (such as poor housing and nutrition) and stress caused by low social status results in health inequalities.
The New Zealand Index of Deprivation uses census data based on income, family status, employment status, qualifications, accommodation, communications and transport to create a scale of socio-economic status. This is applied to neighbourhoods. Decile one is the least deprived and decile 10 the most deprived. There is a strong correlation between deprived areas and the health status of their residents.
Life expectancy and mortality trends are common ways of measuring health status and monitoring inequality. Life expectancy is lower in more deprived areas. In the early 2010s there was an eight-year life-expectancy gap for males and a six-year gap for females between the least and most deprived neighbourhoods.
While all-age mortality rates fell at much the same rate for all income groups in the 1980s and 1990s, the gap between the rates for low- and high-income earners (which researchers call the ratio of mortality) widened over this period. While the overall drop in mortality rates was a positive change, the widening relative gap was not. However, the gap did not increase in the 1990s and early 2000s.
Researchers have suggested that increased income inequality in the 1980s and 1990s (associated with structural reform of the economy) contributed to increased inequality in mortality rates. However, they point out that this inequality also increased in other comparable countries at the same time, and the change was no faster in New Zealand than in countries that did not reform their economies.
Ethnicity is a critical component of health inequalities. Māori and Pacific people have had consistently poorer health than other ethnic groups since the 19th century. Though this is linked to socio-economic status, both populations still have poorer health when factors like income, occupation, education, neighbourhood and personal behaviour are accounted for. Explanations for this include institutional racism (where organisations and structures discriminate against certain ethnic groups, either overtly or unintentionally) and for Māori, the ongoing effects of colonisation.
Over and under
In the 2010s Māori and Pacific people were over-represented in negative health statistics, but under-represented in health-sector employment. In the 2013 census 14.9% of New Zealanders identified themselves as Māori and 7.4% as Pacific people. However, in 2013 only 2.7% of doctors were Māori and 1.8% were Pasifika. In 2015 6.5% of nurses and 9% of midwives were Māori, while 2.6% of nurses were Pasifika.
Life expectancy, mortality and ethnicity
Life expectancy for Māori improved dramatically over the 20th century, and the considerable gap between Māori and Pākehā life expectancy narrowed rapidly after the Second World War. Non-Māori life expectancy increased rapidly in the 1980s and 1990s, but the increases for Māori were small. However, the gap narrowed in the early 21st century. In 2012-14 life expectancy at birth was 83.9 years for non-Māori women, 80.3 for non-Māori men, 77.1 for Māori women and 73 for Māori men. Life expectancy at birth was 78.7 years for Pasifika females and 74.5 years for Pasifika males.
In the early 21st century Māori had the highest all-age mortality rates, followed by Pacific people. The gap in mortality rates between these two groups and Europeans and others (mainly Asians) widened in the 1980s and 1990s. This was probably related to the economic restructuring of the time, which had a big impact on Māori and Pasifika employment and income. The gap narrowed from the late 1990s to the early 2000s, a time when the economy recovered and health policies began to address health inequalities.
The Asian population (which included a large proportion of recent migrants) had the lowest mortality rate over this period. This reflected the good health of most migrants.