State-Level Income Inequality as a Determinant of Suicide Mortality in the United States

Income inequality has been increasing for decades and is now known to be related to many downstream health outcomes, where greater inequality is a predictor of poorer health. Results of investigations into the relationship between income inequality and suicidality have been mixed. This study leverages the most recent data available from the National Longitudinal Mortality Study to investigate the relationship between state-level income inequality and suicide mortality. A series of rigorously controlled logistic regression models, employing multiple measures of inequality, and various suicide mortality case-control specifications are used to investigate the phenomenon. Results indicate that the odds of suicide mortality increase with inequality, and this result is invariant across all models. A reduction in the Gini coefficient from the highest to lowest values of income inequality observed in U.S. states may reduce the odds of suicide mortality by 20 percent to 55 percent or more. Findings have application for social workers and other mental health professionals with respect to clinical assessment and treatment. Likewise, community organizers, policy advocates, and legislators should be aware that policy solutions reducing income inequality in the United States are a mechanism for alleviating the suicide mortality burden.