Income Inequality and Mortality: The Costa RIcan Case
In recent decades there has been much debate on the extent to which income inequality affects health outcomes. The majority of studies in this literature have examined the relationship between income distribution and health outcomes in the contexts of high-income nations. This dissertation evaluates both the ecological and individual-level relationship between income inequality and mortality in the context of a middle-income country, Costa Rica. The Costa Rican case is particularly interesting because its strong social safety net, political organization, and history limit the effects of income inequality on health through indirect channels. Using 20 years of household data, this study begins by documenting changes in income inequality at the canton level. These data reveal that on average inequality has been growing at an annual rate of 0.5%. Using these inequality data, Vital Statistics Mortality records, and longitudinal methods, this study next examines whether cantons with greater growth in inequality also experienced increasing mortality. The analyses indicate that there is no relationship between changes in income inequality and changes in all-cause mortality; however, a relationship does exist for specific causes of death. Area-level inequality was found to be associated with an increase in suicide mortality rates, and a decrease in cardiovascular, respiratory cancer, and breast cancer mortality rates. At the individual-level survival analysis was applied to a new census-mortality linked dataset that allows for a 20-year prospective follow-up. These individual level analyses also test whether income inequality disproportionately affects the poor. In the case of all-cause mortality, the results suggest that there is no association between income inequality and time to death for either the entire sample or for the poor. Contrary to expectations the magnitudes of the estimated effects indicate that residents living in areas with increasing income inequality had a survival advantage for cardiovascular mortality, which further confirms the results found at the ecological level. Overall, this study finds that while inequality has been increasing in Costa Rica, it had limited effect on mortality, indicating that in an environment where safety net services are available, the negative effects of income inequality may be limited to suicide mortality.