I examined the association between income inequality and population health and tested whether this association was mediated by interpersonal trust or public expenditures on health. Individual data on trust were collected from 48 641 adults in 33 countries. These data were linked to country data on income inequality, public health expenditures, healthy life expectancy, and adult mortality. Regression analyses tested for statistical mediation of the association between income inequality and population health outcomes by country differences in trust and health expenditures. Income inequality correlated with country differences in trust (r = -0.51), health expenditures (r = -0.45), life expectancy (r = -0.74), and mortality (r = 0.55). Trust correlated with life expectancy (r = 0.48) and mortality (r = -0.47) and partly mediated their relations to income inequality. Health expenditures did not correlate with life expectancy and mortality, and health expenditures did not mediate links between inequality and health. Income inequality might contribute to short life expectancy and adult mortality in part because of societal differences in trust. Societies with low levels of trust may lack the capacity to create the kind of social supports and connections that promote health and successful aging.
