Associations Between Income Inequality and Mortality Among U.S. States

The Importance of Time Period and Source of Income Data

Previous research has documented an association between income inequality and mortality in the United States. To further explore this association, this study compared census data and tax return income data for the period between 1949 and 1999 with mortality rates for each decade. Data was drawn from the U.S. Census Bureau, Internal Revenue Service, and reports from the National Center for Health Statistics and Behavioral Risk Factor Surveillance System data.

Key Findings:

  • The decades 1949, 1959 and 1969 showed little association between income inequality and mortality.
  • There was an association between income inequality and mortality in 1979 which became stronger in 1989 and weaker in 1999.
  • The 1989 and 1999 associations were weaker when the analysis used tax return data rather than census data, reflecting changes in the highest income bracket.