Friday 13 August 2010 12:33pm
Increasing differences in life expectancy between high and low income groups since the early 1980s provide evidence of the impact of social determinants, such as income, on inequalities in health in New Zealand, according to latest research from the University of Otago, Wellington.
This study, from the Health Inequalities Research Programme, has just been published in the New Zealand Medical Journal.
This research investigates trends in survival and life expectancy by ethnicity, income and smoking, using data from census cohorts from 1981-2004, Statistics New Zealand life-tables and the New Zealand Census-Mortality Study that links mortality and census data. The uniqueness lies in linking these datasets so life expectancy by combinations of these demographic groups could be investigated.
“One of the key findings of our research is that ‘gaps’ between income groups with regard to survival and life expectancy consistently increased from 1981 to 2001,” explains lead researcher Dr Kristie Carter.
The ‘gap’ in life expectancy widened from 1981-2001 between low income and high income, in males from 4.4 years in 1981 to 6.5 years in 2001, and in females from 3.3 years in 1981 to 4.7 years in 2001.
“This is despite the fact that life expectancy improved for most groups in this period; some groups have clearly done much better than others.”
Overall life expectancy improved the most in the high-income non-Māori population over time, males (6.7 years) and females (5.3 years).
When specific sub-population groups are compared, life expectancy of high-income Māori was consistently lower than low-income non-Māori over time.
“It is unclear whether the positive improvements in life expectancy and the subsequent negative increases in inequalities between groups are directly linked to either economic, social or health policies, due to the complex nature of the relationships,” Dr Carter says. “But it is inescapable that they would have had some impact.”
Other results show:
- improvements in life expectancy in females over the last 20 years are not as great as those experienced in males
- female life expectancy started at a higher level than males so this may be a closing of the gender gap in life expectancy
- the gap in life expectancy between Maori and non-Maori widened from 1981 to 1996, then stabilised to 2004
- the differences in life expectancy between current and never smokers was around 7 years during 1996-99
This study was funded by the Ministry of Health and the Health Research Council.
For further information contact
Dr Kristie Carter
University of Otago, Wellington
Tel +64 4 806 1617
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