Income Inequality and Mortality in Costa Rica

Sepideh Modrek, University of California, Berkeley

The hypothesis that income inequality adversely affects health outcomes has been extensively debated in the economics, demography, and public health literature in recent decades. This study evaluates the relationship between income inequality and mortality in the context of a middle-income country, Costa Rica, whose social structure and history confer the unique benefit of being less susceptible to common sources of confounding. Approximately 16,000 individuals aged 30 or more were selected from the 1984 Census and linked to the Costa Rican National Death Registry until Dec. 31, 2007. Gompertz models were used to estimate the relative risk of mortality for various indicators of area-level inequality, while controlling for area and individual-level confounders. The results in the preferred models suggest residents of areas with higher income inequality in 1989 exhibit lower survival rates over the following 19 years. These results were also corroborated with an alternate measure of inequality, relative deprivation.