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Relation between income inequality and mortality: empirical demonstration
M C Wolfson1, G Kaplan, J Lynch
1Institutions and Social Statistics, Branch Statistics, Canada Ottawa, Canada K1A 0T6.
The Western Journal of Medicine
|August 30, 2008
Summary
Income inequality and mortality associations are not just statistical artifacts. Observed links between income inequality and mortality at the state level persist beyond artifact explanations, highlighting broader health determinants.
Area of Science:
- Public Health
- Sociology
- Biostatistics
Background:
- Population-level associations between income inequality and mortality are debated.
- The statistical artifact hypothesis suggests these associations may stem from individual-level income-mortality relationships.
- Clarifying this relationship is crucial for understanding health disparities.
Purpose of the Study:
- To quantify the extent to which observed income inequality-mortality links are statistical artifacts.
- To differentiate between artifactual and genuine state-level associations.
Main Methods:
- Indirect "what if" simulation using individual-level income-mortality data.
- Constructed hypothetical state-level mortality rates assuming the statistical artifact argument was 100% correct.
- Utilized 1990 US Census data, CDC mortality data, and National Longitudinal Mortality Study regressions.
Main Results:
- Simulated hypothetical mortality showed a weaker association with income inequality than observed mortality.
- The statistical artifact explanation could not fully account for the observed state-level income inequality-mortality link.
- A significant association between income inequality and mortality remained after accounting for potential artifacts.
Conclusions:
- Observed associations between US state-level income inequality and mortality are not entirely explained by statistical artifacts.
- A genuine, substantial association between income inequality and mortality exists at the state level.
- This underscores the importance of social factors and the social milieu in determining population health outcomes.
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