Identifying the Causes of the Stagnation in National U.S. Cardiovascular Disease Mortality - PROJECT SUMMARY Since 2010, U.S. life expectancy improvements have stalled and in certain years declined. Much attention to this stall has focused on the role of rising drug overdose deaths. In published work, however, our team has identified stagnating declines in cardiovascular disease (CVD) mortality to be the major culprit. A failure to improve CVD mortality puts the U.S. at risk for sustained declines in inter-generational life expectancy. However, to date, research has not identified why U.S. CVD mortality is stagnating and, for some age groups, increasing. Using novel approaches, we will investigate four hypotheses for stagnating CVD mortality: (a) rising obesity and the resulting increase in CVD risk at a national level, (b) plateauing declines in cigarette smoking, (c) survivor effects attributable to improved survival among those with a history of a CVD event, and (d) rising levels of socio-economic vulnerability and geographic disparities. Aim 1 identifies the role that changes in obesity (Aim 1a) and cigarette smoking levels (Aim 1b) are having on national-level CVD mortality. We will reconstruct cohort histories of obesity to model the aggregate effects of both current and earlier-in-life obesity incorporating the dynamics of obesity duration in the population across time. We will provide the first estimates of the role of slowdowns in the decline in cigarette smoking use to CVD mortality trends by extending the Preston Glei Wilmoth approach to cause-specific mortality. We will also apply g-method approaches to identify the joint effects of obesity and smoking accounting for the dynamic relationship between the two variables. We will provide new estimates of the changing prevalence, treatment, and control of three other established CVD risk factors (diabetes, hypertension, high cholesterol) (Aim 1c). Aim 2 investigates “survival effects”, namely that improved survival among those with a history of stroke or a heart attack have accumulated in the population raising the overall frailty of the population. We will apply a novel simulation to quantify its role. Aim 3 turns the lens to disparities and provides an in-depth accounting of heterogeneity in recent CVD trends by geography, race, nativity and socioeconomic status. Examining subpopulation heterogeneity will reveal whether patterns of CVD mortality align with those of diseases of despair. We will apply the methods developed in Aims 1 and 2 to account for disparities in levels and trends in CVD mortality across population subgroups. We will also explicitly investigate the role of the shifting population composition of the United States with respect to nativity and race/ethnicity. The stagnation in U.S. CVD mortality declines has now been evident for a decade without a clear explanation. The COVID-19 pandemic may only worsen existing trends. Given the magnitude of the change in the CVD mortality trajectory and the fact that it is now affecting Americans of most age groups indicates that more than one causal factor is responsible. This project will be a comprehensive and rigorous treatment of leading explanations for the stagnation.