Mediating Effect of Established Risk Factors on Association Between Social Determinants and Cardiovascular Disease Mortality

Abstract

Background: Social determinants of health (SDOH) contribute to increased cardiovascular disease (CVD) mortality.

Objectives: The authors investigated the mediating effects of behavioral and clinical risk factors in the association between SDOH and CVD mortality.

Methods: A total of 50,808 National Health and Nutrition Examination Survey participants aged ≥20 years were included in this analysis. Data on social, behavioral, and clinical risk factors were collected in each National Health and Nutrition Examination Survey, and CVD deaths were ascertained through linkage to the National Death Index with follow-up through 2019. Multiple mediation analysis was used to examine the contributions of behavioral and clinical risk factors to the SDOH-CVD mortality association.

Results: The mean age of participants was 47.2 years, and 48.8% were male. A dose-response association between the number of SDOH and CVD mortality was identified. Individuals with a composite SDOH score ≥ median have a 2.13-fold increased risk of CVD mortality (95% CI: 1.91-2.37) compared to those with a score < median. After adjusting for behavioral and clinical risk factors, the HR was reduced to 1.67 (95% CI: 1.50-1.86). Current smoking (relative contribution 11.4%; 95% CI: 8.1%-14.8%), physical inactivity (7.7%; 95% CI: 4.9%-10.6%), chronic kidney disease (5.5%; 95% CI: 3.8%-7.1%), diabetes (2.0%; 95% CI: 1.1%-2.9%), and unhealthy sleep duration (1.8%; 95% CI: 0.3%-3.3%) significantly mediated the association between CVD mortality and unfavorable SDOH. In aggregate, behavioral and clinical risk factors mediated 30.8% (95% CI: 24.2%-37.5%) of the overall CVD mortality attributable to unfavorable SDOH.

Conclusions: Behavioral and clinical risk factors partially mediate the association between unfavorable SDOH and increased CVD mortality.

Keywords: behavioral risk factors; cardiovascular disease mortality; clinical risk factors; mediating effect; social determinants of health.

Graphical abstract

Figure 1

Conceptual Model of Multiple Mediation Analysis for Social Determinants of Health and Cardiovascular Disease Mortality We hypothesized that cardiovascular disease mortality associated with social determinants of health was partially attributable to established cardiovascular disease risks factors in the U.S. population. Age, sex, and race/ethnicity were confounding factors for those associations. NHANES = National Health and Nutrition Examination Survey.

Figure 2

HR and 95% CI of Cardiovascular Disease Mortality Associated With Social Determinants of Health in U.S. Adults ∗Stratified by the National Health and Nutrition Examination Survey (NHANES) cycles and adjusted for age, sex, and race and ethnicity. †Stratified by NHANES cycles and adjusted for age, sex, race, and ethnicity, and all other SDOH listed in the figure. SDOH = social determinants of health.

Figure 3

Mediation Effects of Behavioral and Clinical Risk Factors on Social Determinants of Health and Cardiovascular Disease Mortality Association The composite SDOH score was created based on the number of unfavorable individual SDOH variables, weighted by their regression coefficients from the multivariable Cox regression models, and rescaled to a range of 0 to 1. A larger SDOH score indicates a higher number of unfavorable individual SDOH, with 0 representing no unfavorable determinants and 1 representing 8 unfavorable determinants. HDL = high-density lipoprotein; other abbreviations as in Figures 1 and 2.

Central Illustration

Behavioral and Clinical Risk Factors Mediate a Moderate Proportion of Social Determinants of Health and Cardiovascular Disease Mortality Association Established behavioral and clinical risk factors, including cigarette smoking, physical inactivity, unhealthy sleep duration, diabetes, and chronic kidney disease, mediated 30.8% of the overall cardiovascular disease mortality attributable to unfavorable social determinants of health. The direct effect accounted for 69.2% of cardiovascular disease mortality attributable to unfavorable social determinants of health.