Income inequality and socioeconomic gradients in mortality.
OBJECTIVE
We investigated whether the processes underlying the association between income inequality and population health are related to those responsible for the socioeconomic gradient in health and whether health disparities are smaller when income differences are narrower.


METHODS
We used multilevel models in a regression analysis of 10 age- and cause-specific US county mortality rates on county median household incomes and on state income inequality. We assessed whether mortality rates more closely related to county income were also more closely related to state income inequality. We also compared mortality gradients in more- and less-equal states.


RESULTS
Mortality rates more strongly associated with county income were more strongly associated with state income inequality: across all mortality rates, r= -0.81; P=.004. The effect of state income inequality on the socioeconomic gradient in health varied by cause of death, but greater equality usually benefited both wealthier and poorer counties.


CONCLUSIONS
Although mortality rates with steep socioeconomic gradients were more sensitive to income distribution than were rates with flatter gradients, narrower income differences benefit people in both wealthy and poor areas and may, paradoxically, do little to reduce health disparities.
Wilkinson
Richard G
RG
Division of Epidemiology and Public Health, University of Nottingham Medical School, Nottingham NG7 2UH, UK. richard.wilkinson@nottingham.ac.uk
Pickett
Kate E
KE
D000328:Adult; D003430:Cross-Sectional Studies; D006297:Health Services Accessibility; D006301:Health Services Needs and Demand; D054624:Health Status Disparities; D006801:Humans; D007182:Income; D008875:Middle Aged; D009026:Mortality / Q000639:trends*; D011203:Poverty; D011634:Public Health; D012044:Regression Analysis; D040241:Social Marketing; D012959:Socioeconomic Factors; D014481:United States