Area socioeconomic inequality and suicide mortality: contrasting common measures using National Violent Death Reporting System and linked administrative data.

Abstract

Area economic inequality may underlie social disparities in suicide mortality (SM). Differences in measuring inequality contribute to variability across empirical evidence. We contrasted common income measures-absolute poverty, Gini inequality index, Index of Concentration at the Extremes (ICE)-and examined their associations with age- and sex-standardized SM across 1381 US counties. We used the 2006-2019 National Violent Death Reporting System linked to 2006-2010 administrative data on socioeconomic factors and a Bayesian spatial multilevel approach. Compared to affluent areas, poorer areas had the highest relative risk (RR) of SM (ICE RR, 1.24; 95% credible interval [CI], 1.17-1.31; absolute poverty RR, 1.33; 95% CI, 1.25-1.41). Gini inequality was not linearly associated with SM. Cross-classifying Gini × ICE showed that the highest-risk areas had concentrated poverty (ICE) but varying Gini inequality. These high-risk, poverty-segregated areas were more often medically underserved, had lower population density, and high unemployment. African American or Indigenous suicide decedents frequently resided in high inequality areas, while older, White decedents with military backgrounds more often resided in lower Gini areas. The choice of inequality measure can lead to varied conclusions about social disparities in SM. A comparative approach offers more nuanced understanding of underlying socioeconomic marginalization.