Does a rising tide of health outcomes lift all boats?

Politicians who favor reducing taxes and other financial policies that predominantly benefit "the rich" have argued that wealthy people have an outsized influence on the general health of the economy, and that their prosperity will benefit lower earners by directly or indirectly creating new or higher-paying jobs. A more pithy expression for this sentiment that President Kennedy first made famous is: "a rising tide lifts all boats." I don't have the expertise to comment on the veracity of this statement in an economic sense, but a recent study in Preventing Chronic Disease by Dr. David Kindig and colleagues asked an analogous question: can states simultaneously improve health outcomes and reduce health outcome disparities?

The study authors used age-adjusted mortality data from a Centers for Disease Control and Prevention database to compare the annual percent change in combined black and non-Hispanic white mortality by state with the annual change in black-white mortality disparities in those states from 1999 through 2013. Overall, in states where sufficient mortality data was available for analysis, combined-race mortality fell by a mean of 1.1% and the black-white disparity fell by a mean of 3.6% per year. However, there was no relationship between combined mortality and racial disparity reductions across states. A few states (Georgia, Maryland, Massachusetts) experienced above average improvements on both measures, but others (Oklahoma) were below average on both, and most states experienced relatively greater improvement on one measure than on the other.

Figure courtesy of CDC.

The implications of these findings are that strategies to improve health across all populations (the "rising tide") may be different from those aimed at eliminating racial health disparities ("all boats"). They also provide a baseline for what state health departments may reasonably expect when setting health improvement and disparity reduction goals in future years.