Swing voting in the 2016 presidential election in counties where midlife mortality has been rising in white non-Hispanic Americans

Understanding the effects of widespread disruption of the social fabric on public health outcomes can provide insight into the forces that drive major political realignment. Our objective was to estimate the association between increases in mortality in middle-aged non-Hispanic white adults from 1999 to 2005 to 2009-2015, health inequalities in life expectancy by income, and the surge in support for the Republican Party in pivotal US counties in the 2016 presidential election. We conducted a longitudinal ecological study in 2764 US counties from 1999 to 2016. Increases in mortality were measured using age-specific (45-54 years of age) all-cause mortality from 1999 to 2005 to 2009-2015 at the county level. Support for the Republican Party was measured as the party's vote share in the presidential election in 2016 adjusted for results in 2008 and 2012. We found a significant up-turn in mortality from 1999 to 2005 to 2009-2015 in counties where the Democratic Party won twice (2008 and 2012) but where the Republican Party won in 2016 (+10.7/100,000), as compared to those in which the Democratic Party won in 2016 (−15.7/100,000). An increase in mortality of 15.2/100,000 was associated with a significant (p < 0.001) 1% vote swing from the 2008-2012 average to 2016. We also found that counties with wider health inequalities in life expectancy were more likely to vote Republican in 2016, regardless of the previous voting patterns. Counties with worsening premature mortality in the last 15 years and wider health inequalities shifted votes toward the Republican Party presidential candidate. Further understanding of causes of unanticipated deterioration in health in the general population can inform social policy.