Income Inequality and Population Health: Examining the Role of Social Policy

Studies of the relationship between income inequality and life expectancy often speculate about the role of policy, but direct empirical research is limited. Drawing on the neo-materialist perspective, we examine whether the longitudinal association between income inequality and life expectancy is mediated and moderated by policy liberalism in U.S. states (2000–2014). More liberal policy contexts are characterized by greater efforts to regulate the economy, redistribute income, and protect vulnerable groups and lesser efforts to penalize deviant social behavior. We find that state-level income inequality is inversely associated with policy liberalism and life expectancy. The association between income inequality and life expectancy was not mediated by policy liberalism but was moderated by it. The association is attenuated in states with more liberal policy contexts, supporting the neo-materialist perspective. This finding illustrates how states like New York and California (with liberal policy contexts) can exhibit high income inequality and high life expectancy.