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Background
It is a truism that poverty is bad for health. Relative as well
as absolute forms of poverty are associated with adverse health
outcomes. Yet the precise links between financial circumstances
and health are not well understood. In part, this is because most
analyses of income and health are based on data collected at a single
point in time. What is actually required is information that monitors
changes in an individual's circumstances. Although some people face
long periods of sustained financial hardship, a large number of
others move into and out of poverty in various ways and for differing
periods of time. These kinds of income dynamics, as they are known,
may have important implications for health outcomes. For example,
are long periods of time spent living on a low income more or less
damaging for health than very large but temporary reductions in
income? Or, are there specific stages of the life course, like childhood,
when low levels of income are particularly harmful for health prospects?
The purpose of this project is to investigate these and similar
questions in a British context.
Aims and
Objectives
The project has three aims:
- to develop
a theoretical framework that can account for the observed links
between levels of, and changes in, income and health;
- to investigate
the effects of both short-term fluctuations in income and longer-term
measures of more 'permanent' income on different dimensions of
health using longitudinal datasets and appropriate econometric
techniques;
- to explore
the economic and social policy implications of the relationship
between income and health.
Study Design
Ideally, the data required for this project would include information
on people's income and health at frequent intervals from childhood
through all stages of adult life. Unfortunately, such a dataset
does not exist in Britain. The most suitable of the available datasets
for this project are the National Child Development Survey (NCDS)
and the British Household Panel Survey (BHPS).
The NCDS, a
birth cohort study that began in 1958, allows the examination of
three distinct income and health relationships: parental income
and the health of an individual during childhood and early adulthood;
an individual's current health and their past income; and an individual's
present income and health. The BHPS, which has collected panel data
in 5 annual sweeps to date, permits the examination of the volatile
nature of financial circumstances and their implications for health.
Both of these datasets will be used to determine how, and to what
extent, levels and changes in income affect different dimensions
of health for individuals.
Sophisticated
statistical modelling is required to explore the many possible ways
that different aspects of income dynamics might affect health. One
critical requirement is to adjust for the possibility that health
influences income as well as income having an impact on health,
at the same time as taking account of a wide range of other determinants
of health. The project will employ the latest econometric techniques
to investigate the complex relationship between income and health
over time.
Policy Implications
The final part of the project will review the policy implications
of the study and consult with the policy community. A central goal
of the project will be to establish good links with, and disseminate
findings to, key policy makers and practitioners. The intention
is to provide detailed guidance about when, and in what ways, different
kinds of policy instruments could be used to improve the health
status of those people who are vulnerable to problems associated
with fluctuating or inadequate incomes.
Project Summary
Reducing poverty in childhood and across the lifecourse is a
key objective of the government's strategy to reduce health inequalities
and promote social inclusion. The aim of this project was to investigate
the relationship between an individual's financial circumstances
and their health over time and to consider the implications of findings
for policy development.
Four sets of
analyses were conducted. Firstly, analyses of the British Household
Panel Survey (BHPS) were undertaken to explore the relationship
between income and health over relatively short periods of time
(over 6 consecutive years of the Survey). This shed light on the
issue of health selection (on whether the causal pathways run from
poverty to poor health or from poor health to poverty) and explored
the effect of income dynamics per se on health. Secondly, the 1958
birth cohort study, the National Child Development Study (NCDS)
was employed to examine the role of income in childhood for adult
socio-economic and health outcomes. Thirdly, a conceptual framework
was developed to explore the role of income for health inequalities
within a lifecourse perspective using the BHPS and the NCDS. Again,
social selection (poor health leading to poor circumstances in adulthood)
was taken into account. Finally, drawing on these two sets of analyses,
an assessment of policies introduced by the New Labour government
in the 1997-9 period was undertaken, to review its anti-poverty
strategy and to identify key areas for policy development.
Key findings
- The study
brought together for the first time evidence from two British
longitudinal studies to provide a more detailed picture of the
relationship between income and health over the lifecourse. It
is recognised, however, that unraveling the complex temporal relationships
between poverty and health presents major theoretical and methodological
challenges. Measurement error and selection bias pose real challenges
for researchers.
- Analyses
of 6 consecutive years of BHPS data found a significant association
between adult income and health, for a range of outcome measures
and controlling for health selection. Persistent poverty appears
to be particularly harmful for health, with a stronger relationship
between measures of income over time than income measured at one
point in time. This suggests that it is the accumulation of poor
financial circumstances which is detrimental to health.
- Analyses
of the NCDS suggest that family income plays an important role
in the pathway to adult health. While family income in childhood
had a direct effect on a child's health in early adulthood (age
23), its primary effect was indirect. Family income operated primarily
through educational attainment. Educational qualifications, in
turn, display a significant correlation with both living standards
and health in adult life. Other parental influences, and particularly
family composition and time invested in quality parenting, were
also found to be important factors in the pathways to health in
early adulthood.
- In analyses
of the NCDS, current circumstances also mattered. The detrimental
effects - direct and indirect - of low family income in childhood
were reinforced by the effects of low current income.
- The results
suggest that policies to reduce poverty, especially for families
with children, should be an essential ingredient in any concerted
effort to tackle health inequalities. However, the evidence that
the health effects of childhood poverty operate through educational
pathways suggests that other policy developments, particularly
to promote educational opportunities, are also required.
- The policy
analysis focused on measures introduced in the first two years
of the New Labour government (1997-1999) to tackle poverty. It
suggests that, while an important beginning, these policies had
only marginal effects. Moreover, some key groups were excluded
from the government's anti-poverty strategy. In particular, single
people and couples without children experienced average reductions
in their real living standards across this period. The evidence
from the longitudinal analyses suggests that this reduction may
affect their health adversely.
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