The report 'Living Standards and Health: New Zealand 2006/07' compares two measures of living standards that were included in the 2006/07 New Zealand Health Survey, and investigates the associations between living standards and health.
Living standards are a direct measure of an individual's or family's actual consumption of goods and services that are essential for wellbeing. Many factors influence an individual's living standards, including income, assets, non-income contributions, special demands on income, adverse life events, and human and social capital. The 2006/07 New Zealand Health Survey included two measures of living standards: the New Zealand Individual Index of Deprivation (NZiDep), developed by the University of Otago, Wellington; and the Economic Living Standards Index - short form (ELSI), developed by the Ministry of Social Development. Both measures were found to perform well in the survey.
Methodology
The data source for this study was the 2006/07 New Zealand Health Survey (NZHS), which surveyed a nationally representative sample of 12,488 adults aged 15 years and over drawn from the usually resident population of New Zealand.
The survey collected data on self-reported physical and mental health status, doctor-diagnosed chronic conditions, risk and protective behaviours, body mass index, use of health services and sociodemographic characteristics, including living standards.
Two measures of living standards were included in the survey: the Economic Living Standards Index short form (ELSISF) and the New Zealand Individual Deprivation Index (NZiDep).
The ELSISF is a 25-item instrument developed between 2000 and 2002 by the Ministry of Social Development, which has since included it in four population-based surveys. The NZiDep is an eight-item instrument developed by the Wellington School of Medicine (University of Otago, Wellington) in 2001–2002. Its developers describe it as a measure of ‘individual-level deprivation’: a construct similar to ‘living standard’ as that term is used in this document.
The NZiDep has not previously been included in any population-based survey, although it is included in the ‘Health’ supplement to the Survey of Families, Income and Employment (SoFIE). Logistic regression was used to investigate associations between living standards and health, adjusting for the confounding factors of sex, age, ethnicity, urban/rural residence, sole parenthood status, housing tenure, employment status, education, equivalised household income and (in some models) private health insurance. All results were weighted to the estimated 30 June 2007 New Zealand population aged 15 years and over
Key Results
- Living standards are significantly associated with health outcomes, health risk behaviours and health service use. These associations are direct, strong and graded.
- There are particularly strong associations between living standards and psychological distress, as well as between living standards and rates of unmet need for a general practitioner in the past year.
- Living standards act on health independently of income, as well as (partially) mediating the effect of income.
- Living standards should continue to be monitored in future New Zealand health surveys, along with measures of socioeconomic position such as equivalised household income.
Both of the two candidate instruments (ELSISF and NZiDep) are recommended for use in future studies or surveys: the choice between the two should depend on the specific context and purposes of the research.