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

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.