HLTB41H3 Chapter Notes - Chapter 4: Environmental Health, Social Capital, Canadian Studies
Chapter 4: Income, Income Distribution, and Health in Canada
SDOH- Canadian Perspective
-National Public Health Program: includes a multitude of health objectives in the domains
of chronic disease, unintentional injury, infectious disease, environmental health, workplace
health, and social health !
-Two general types of studies on income and health:!
1. Those assessing the relationship bw income and health
2. Those assessing the relationship bw income inequality and health
Characteristics of Income-Health Studies
-Many critiques pertain to defining poverty. Other pertain to suitable measures of poverty,
which usually involve income !
-income measures do not necessarily encompass factors such a social deprivation and social
capital: the social aspects of poverty!
-Studies may use data in which the united measurement is at the macro (population) level
rather than at the micro (individual) level!
-Macro-level analyses called ecologic studies
-Macro- may also be subject to a bias called ecologic fallacy—occurs when macro-level
data are used to make inferences at the individual level !
-Criticism of individual level study design—ie cross-sectional studies that assess the poverty-
health relationship at one point in time do not allow one to determine whether poverty
preceded poor health!
-In fact, it is feasible that poor health precedes poverty!
-This bias is called reverse causation
-Although all measures of poverty are relative, one option is to conceptualize poverty as
either absolute, relative, or subjective!
-Absolute Poverty: refers to having less than an absolute minimum income level based on
the cost of basic needs. One of the disadvantages of this definition is that it is difficult to
objectively select a minimum set of necessities. Another disadvantage is that the cut-off
changes over time. Although there is no official poverty line in Canada, the Statistics Canada
low income cut off (LICO) has traditionally been used !
-Recently the Market Basket Measure (MBM) has been used as another tool to measure
poverty!
-Relative Poverty: refers to having less than the average standard in society. This form of
poverty is often measured as the proportion of individuals below a certain percentage of the
median income !
-Subjective Poverty: refers to individuals feeling that they do not have enough to meet their
needs. Information on subjective poverty can be obtained from surveys. In industrialized
countries, there is a general consensus that relative measures of poverty are more
appropriate for studies on income and health. In practice, however, studies tend to vary
greatly on the type of indicator used to measure poverty !
-Some of the indicators used to measure poverty in ecologic studies of income inequality
include:!
1. The proportion of aggregate income earned by the poorest proportion of households
2. The ratio of income earned by the upper 90th percentile to the 10th percentile of
households
3. A multitude of other indices
-these studies have been critiqued for arbitrarily choosing indicators or for using data-driven
indicators!
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-Critique has been countered as income studies usually reach the same conclusion
irrespective of the indicator used!
-the indicators selected for study may have other drawbacks, some of which may have
implications for identifying the income health relationship:!
4. The indicator may not reflect annual disposable income. Ideally, income should be
calculated after taxes and governmental transfers. Likewise, income should account for
costs of public services. If services such as health care are not publicly financed,
disposable income will be reduced since individuals who rely more heavily on these
services will have to pay out of pocket!
5. The household composed of more than one person, the indicator may not account for the
advantage of shared resources. Researchers have proposed equivalence scales to
calculate income per person; however, the choice of equivalence scale may not be
objective. Also equivalence scales may not adjust for unequal sharing of sharing within
families !
6. The indicator may not take into account volatility of income. Long-term measured of
income may be more appropriate. Alternatively, it may be that acute changes in income are
more important determinants of health !
7. Indicators do not take into account accumulated assets or debts !
8. Indicators do not account for time required to acquire income!
9. It may be that depth of poverty, or just how far income falls short of the poverty line, is
more important !
10. Similarly, duration of poverty may be important!
11. Timing of poverty during the life cycle may play a role. Exposure to poverty during the early
years of a child’s life may have a greater effect on health!
12. Study may not adequately adjust for other factors, known as confounders, which could
account for the income-health relationship!
Canadian Studies on Income and Health
Income Inequality and Health
-Income Inequality: the extent to which income is unequally distributed in a population !
-In an early study, using consensus data and vital statistics, Ross and colleagues found no
relationship bw income and mortality in Canada—-but a strong relationship in the US—
income inequality was defined as percentage of total household income received by the
poorest 50% of households—authors speculate that the social policies widely present in
Canada, but less in the US, could partly account for the differences in mortality !
-In a later study using survey data that accounted for neighbourhood income, found that
income inequality was associated with poor self-reported health in Toronto, but not with
chronic conditions or distress (Hou&Chen)— in their analysis, income inequality was
measured with the coefficient of variation for family income!
-Xi and colleagues also found that income inequality, measured as the Gini coefficient of
Ontario Public Health unites, was associated with poor self-reported health beyond
individual and neighbourhood income !
-More recently, Auger and colleagues, showed that income inequality was strongly
associated with mortality among non-immigrants in Canada—the association was more
pronounced for alcohol and smoking-related causes of death!
-Using Canadian survey data, McLeod and colleagues, did not find a relation bw self reported
health and income inequality (measured as the percentage of total income for the bottom
50% of the income distribution !
-thus, depending on the study methodology, differing results have been obtained
-Consequently, the association bw income inequality and health remains a subject of
great debate
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