Association Between County-Level Change in Economic Prosperity and Change in Cardiovascular Mortality Among Middle-aged US Adults

Abstract

Importance: After a decline in cardiovascular mortality for nonelderly US adults, recent stagnation has occurred alongside rising income inequality. Whether this is associated with underlying economic trends is unclear.

Objective: To assess the association between changes in economic prosperity and trends in cardiovascular mortality in middle-aged US adults.

Design, setting, and participants: Retrospective analysis of the association between change in 7 markers of economic prosperity in 3123 US counties and county-level cardiovascular mortality among 40- to 64-year-old adults (102 660 852 individuals in 2010).

Exposures: Mean rank for change in 7 markers of economic prosperity between 2 time periods (baseline: 2007-2011 and follow-up: 2012-2016). A higher mean rank indicates a greater relative increase or lower relative decrease in prosperity (range, 5 to 92; mean [SD], 50 [14]).

Main outcomes and measures: Mean annual percentage change (APC) in age-adjusted cardiovascular mortality rates. Generalized linear mixed-effects models were used to estimate the additional APC associated with a change in prosperity.

Results: Among 102 660 852 residents aged 40 to 64 years living in these counties in 2010 (51% women), 979 228 cardiovascular deaths occurred between 2010 and 2017. Age-adjusted cardiovascular mortality rates did not change significantly between 2010 and 2017 in counties in the lowest tertile for change in economic prosperity (mean [SD], 114.1 [47.9] to 116.1 [52.7] deaths per 100 000 individuals; APC, 0.2% [95% CI, -0.3% to 0.7%]). Mortality decreased significantly in the intermediate tertile (mean [SD], 104.7 [38.8] to 101.9 [41.5] deaths per 100 000 individuals; APC, -0.4% [95% CI, -0.8% to -0.1%]) and highest tertile for change in prosperity (100.0 [37.9] to 95.1 [39.1] deaths per 100 000 individuals; APC, -0.5% [95% CI, -0.9% to -0.1%]). After accounting for baseline prosperity and demographic and health care-related variables, a 10-point higher mean rank for change in economic prosperity was associated with 0.4% (95% CI, 0.2% to 0.6%) additional decrease in mortality per year.

Conclusions and relevance: In this retrospective study of US county-level mortality data from 2010 to 2017, a relative increase in county-level economic prosperity was significantly associated with a small relative decrease in cardiovascular mortality among middle-aged adults. Individual-level inferences are limited by the ecological nature of the study.

Figure 1.. Counties by Tertile of Change in Economic Prosperity and Change in Age-Adjusted Cardiovascular Mortality Rates (40- to 64-Year-Old Adults)

Maps are based on the US National Atlas Equal Area Projection and reflect county geographic size and not population. A, Change in economic prosperity is the unweighted mean of the ranks for change in the 7 markers of economic prosperity between baseline (2007-2011) and follow-up (2012-2016). A higher mean rank indicates a greater relative increase or lower relative decrease in economic prosperity compared with other counties. The mean rank for change in economic prosperity ranged from 5.4 to 43.8 for the lowest tertile (n = 1041), 43.8 to 56.0 for the intermediate tertile (n = 1041), and 56.1 to 91.9 for the highest tertile (n = 1041); 20 counties did not have data available and were not included. The lightest hue indicates relative improvement in prosperity. B, The change in age-adjusted cardiovascular mortality was −611 to −14 deaths per 100 000 individuals in the lowest tertile (n = 1041), −14 to 21 in the intermediate tertile (n = 1041), and 21 to 666 in the highest tertile (n = 1041); 20 counties did not have data available and were not included. The lightest hue indicates a declining or stable cardiovascular mortality rate. The primary analysis in Table 3 accounts for changes in mortality rates across all years from 2010 to 2017. Distribution of baseline economic prosperity levels and annual cardiovascular mortality rates across the US are available in eFigures 2, 4, 5, 6, 7, 8, 9, 10, and 11 in the Supplement.

Figure 2.. Population-Weighted Mean Annual Age-Adjusted Mortality Rates (40- to 64-Year-Old Adults) by Tertile of Change in Economic Prosperity

Change in economic prosperity is the unweighted mean of the ranks for change in the 7 markers of economic prosperity between baseline (2007-2011) and follow-up (2012-2016). A higher mean rank indicates a greater relative increase or lower relative decrease in economic prosperity compared with lower-ranked counties. The mean rank for change in economic prosperity ranged from 5.4 to 43.8 for the lowest tertile (n = 1041), 43.8 to 56.0 for the intermediate tertile (n = 1041), and 56.1 to 91.9 for the highest tertile (n = 1041). Counties with economic prosperity markers unavailable were not included. ^aAll cardiovascular disorders include ischemic heart disease and stroke.