Have states' mortality rates become more unequal in the last three decades?

State-level differences in the mortality rates of middle-aged Americans increased by 70% between 1992 and 2016.

These differences remain even after accounting for changes in income and the prevalence of so-called “deaths of despair.” For example, the age-adjusted mortality rates in California and Ohio were nearly identical in 1992, but by 2016, California’s death rate had dropped sharply while Ohio’s remained almost the same.

Some possible reasons for diverging mortality rates include differences in state funding for health insurance and support of healthy lifestyle choices — reducing smoking, eating a healthy diet, exercising, etc. These policies receive more funding in places where state-level income has historically been high, allowing for decades-old investments that have continued to accrue benefits over time.