University of OtagoWednesday 16 May 2012, 12:26PM
Media release from University of Otago
Short term changes in household income have only small effects on
health, but have more significant impacts if income is affected by
unemployment or chronic health conditions, new research from the
University of Otago, Wellington shows.
In a study published in the Journal of Epidemiology and Community
Health, researcher Dr Fiona Imlach Gunasekara and colleagues found
that an increase of $10,000 in household income over a year
increased the likelihood of improving self-rated health by about
This study used four years of data and observations on more than
7,800 adult respondents from the Survey of Family, Income and
Employment (SoFIE) from 2002 to 2005. This is a Statistics New
Zealand longitudinal survey which follows the same individuals over
Although the overall effect of increases in income on 'self-rated'
health was small, the researchers say this is consistent with
"It's commonly accepted that poverty increases the chance of
poor health," says Dr Gunasekara. "This is true over long periods
of time according to both New Zealand and international research,
particularly in childhood. What our study shows is that changes in
income over the short term don't alter health that much."
However, the SoFIE study did find that becoming unemployed is bad
for 'self-rated' health, with job loss reducing the likelihood of
an individual reporting better health.
Also, for people with two or more chronic health conditions, such
as asthma, stroke, heart disease, mental illness or diabetes, an
increase in income is associated with significantly improved
self-rated health. These people were 10% more likely to report
better 'self-rated' health with a $10,000 increase in household
"This provides a reason to target income support for those
individuals who have chronic conditions," says Dr Gunasekara. "This
may be through health prevention activities and financial
assistance for those with multiple health issues."
Dr Gunasekara emphasises that the study looked only at short term
effects on health from changes in income. It excluded the effect of
chronic or permanent low income on adult health. Other evidence
from New Zealand has shown the significance of chronic poverty over
the course of a person's life.
"We recently found that 21% of our SoFIE respondents are
chronically in low income - that is, have an average before tax
household income of below $27,000 over seven years. This is a high
proportion of respondents and has implications for health."
(See media release at: www.otago.ac.nz/wellington)
Dr Gunasekara says we also know from cohort studies in Dunedin and
Christchurch over many decades that children from low income
families have worse health outcomes as adults than children from
higher income families.
Research linking chronic low income to health using SoFIE data is
currently underway. However, existing evidence suggests that
improving health will be best achieved by measures to reduce
childhood and long term poverty, chronic disease and unemployment
rather than policies that expect 'a quick fix' over short time
This study was funded by the Health Research Council.