Political environment and mortality rates in the United States, 2001-19: population based cross sectional analysis

Abstract

Objective: To assess recent trends in age adjusted mortality rates (AAMRs) in the United States based on county level presidential voting patterns.

Design: Cross sectional study.

Setting: USA, 2001-19.

Participants: 99.8% of the US population.

Main outcome measures: AAMR per 100 000 population and average annual percentage change (APC).

Methods: The Centers for Disease Control and Prevention WONDER database was linked to county level data on US presidential elections. County political environment was classified as either Democratic or Republican for the four years that followed a November presidential election. Additional sensitivity analyses analyzed AAMR trends for counties that voted only for one party throughout the study, and county level gubernatorial election results and state level AAMR trends. Joinpoint analysis was used to assess for an inflection point in APC trends.

Results: The study period covered five presidential elections from 2000 to 2019. From 2001 to 2019, the AAMR per 100 000 population decreased by 22% in Democratic counties, from 850.3 to 664.0 (average APC -1.4%, 95% confidence interval -1.5% to -1.2%), but by only 11% in Republican counties, from 867.0 to 771.1 (average APC -0.7%, -0.9% to -0.5%). The gap in AAMR between Democratic and Republican counties therefore widened from 16.7 (95% confidence interval 16.6 to 16.8) to 107.1 (106.5 to 107.7). Statistically significant inflection points in APC occurred for Democratic counties between periods 2001-09 (APC -2.1%, -2.3% to -1.9%) and 2009-19 (APC -0.8%, -1.0% to -0.6%). For Republican counties between 2001 and 2008 the APC was -1.4% (-1.8% to -1.0%), slowing to near zero between 2008 and 2019 (APC -0.2%, -0.4% to 0.0%). Male and female residents of Democratic counties experienced both lower AAMR and twice the relative decrease in AAMR than did those in Republican counties. Black Americans experienced largely similar improvement in AAMR in both Democratic and Republican counties. However, the AAMR gap between white residents in Democratic versus Republican counties increased fourfold, from 24.7 (95% confidence interval 24.6 to 24.8) to 101.3 (101.0 to 101.6). Rural Republican counties experienced the highest AAMR and the least improvement. All trends were similar when comparing counties that did not switch political environment throughout the period and when gubernatorial election results were used. The greatest contributors to the widening AAMR gap between Republican and Democratic counties were heart disease (difference in AAMRs 27.6), cancer (17.3), and chronic lower respiratory tract diseases (8.3), followed by unintentional injuries (3.3) and suicide (3.0).

Conclusion: The mortality gap in Republican voting counties compared with Democratic voting counties has grown over time, especially for white populations, and that gap began to widen after 2008.

Fig 1

Trends in age adjusted mortality rates (AAMRs) per 100 000 residents of counties voting for Democratic or Republican presidential candidates. Widening gap in AAMR is noted between Democratic and Republican counties. Statistically significant inflection points in annual percentage change (APC) of AAMR occurred for Democratic counties between periods 2001-09 (APC −2.1) and 2009-19 (APC −0.8) and Republican counties between periods 2001-08 (APC −1.4) and 2008-19 (APC −0.2)

Fig 2

Trends in age adjusted mortality rates (AAMRs) per 100 000 residents of counties voting for Democratic or Republican presidential candidates by sex. Widening gap in AAMR is noted between male and female residents of Democratic and Republican counties. (Top lines) Statistically significant inflection points in annual percentage change (APC) of AAMR occurred for male residents of Democratic counties between periods 2001-10 (APC −2.2) and 2010-19 (APC −0.7) and male residents of Republican counties between periods 2001-07 (APC −1.7) and 2007-14 (APC −0.6) with no significant change noted after additional inflection point (straight line) between 2014 and 2019. (Bottom lines) Statistically significant inflection points in annual percentage change of AAMR occurred for female residents of Democratic counties between periods 2001-09 (APC −2.0) and 2009-19 (APC −0.9) and female residents of Republican counties between periods 2001-07 (APC −1.4) and 2007-19 (APC −0.3)

Fig 3

Trends in age adjusted mortality rates (AAMRs) per 100 000 residents of counties voting for Democratic or Republican presidential candidates by race and ethnicity. Widening gap in AAMR is noted most prominently among white residents of Democratic and Republican counties, while the gap appears to narrow for Hispanic residents. AAMR gap for black residents of Democratic and Republican counties oscillates across the study period

Fig 4

Trends in age adjusted mortality rates (AAMRs) per 100 000 population of residents of counties voting for Democratic or Republican presidential candidates by urban-rural location. Widening gaps in AAMR between Republican and Democratic counties are noted across urban-rural spectrum, from large metropolitan areas, medium metropolitan areas, and rural areas

Fig 5

Age adjusted mortality rates (AAMRs) per 100 000 population for the 10 most common causes of death in Democratic and Republican counties in 2001 and 2019. Except for cerebrovascular disease, the gap in AAMR between Republican and Democratic counties increased for every cause of death over the study period driven by heart disease, cancer, chronic lower respiratory tract disease, unintentional injuries (which include drug overdoses), and suicide

Fig 6

Trends in age adjusted mortality rates (AAMRs) per 100 000 population for counties voting for Democratic or Republican governors by state Group from 2001 to 2019. Group A=New Hampshire and Vermont; Group B=Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Florida, Georgia, Hawaii, Idaho, Illinois, Iowa, Kansas, Maine, Maryland, Massachusetts, Michigan, Minnesota, Nebraska, Nevada, New Mexico, New York, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Wisconsin, Wyoming, and Washington DC; Group C=Delaware, Indiana, Missouri, Montana, North Carolina, North Dakota, Utah, Washington, and West Virginia; Group D=Kentucky, Louisiana, and Mississippi; Group E=New Jersey and Virginia