Synergistic and Joint effect of Cardiovascular Health and Social Determinants of Health on Mortality Evidence from a Nationally Representative Cohort

Objectives

To examine whether social determinants of health (SDOH) modify the association between cardiovascular health (CVH), defined by Life’s Essential 8 (LE8), and mortality risk, and to evaluate the protective effects of CVH across different levels of SDOH.

Methods

We analyzed data from 25,885 adults participating in the 2005–2018 National Health and Nutrition Examination Survey (NHANES). SDOH were assessed using eight variables reflecting socioeconomic, healthcare, and living conditions. Each variable was dichotomized according to conventional cut-off values. A value of 0 was assigned to each favorable level and 1 to each unfavorable level, and the sum of these dichotomous measures was used to create a cumulative SDOH score. Participants were then classified into a “more favorable SDOH” group and a “less favorable SDOH” group based on the median of the cumulative score. CVH was derived from LE8 metrics and classified into low, medium, and high categories. Mortality outcomes were determined through linkage to the National Death Index with follow-up through 2019.

Results

A significant interaction between SDOH and CVH on all-cause mortality was observed (Pinteraction=0.007). Among individuals with more favourable SDOH, high CVH was associated with substantially lower risks of all-cause mortality (HR 0.49, 95% CI 0.35–0.69), cardiovascular mortality (HR 0.33, 95% CI 0.18–0.60), and cancer mortality (HR 0.52, 95% CI 0.28–0.97). In the less favourable SDOH group, high CVH remained protective against cardiovascular death (HR 0.42, 95% CI 0.21– 0.83), though associations with all-cause and cancer mortality were attenuated. Sensitivity and competing risk analyses confirmed these findings.

Conclusions

Higher CVH consistently reduced mortality risk, especially among socially advantaged individuals. Interventions targeting both cardiovascular health and social determinants are needed to address disparities in cardiovascular outcomes.

Social determinants of health (SDOH) were selected according to the five domains recommended by Healthy People 2030 and the World Health Organization: economic stability, education access and quality, health care access and quality, neighborhood and built environment, and social and community context. Cardiovascular health was defined by the Life’s Essential 8 (LE8) scoring system, which includes diet, physical activity, tobacco/nicotine exposure, sleep, body mass index (BMI), non–high-density lipoprotein cholesterol (non-HDL-C), blood glucose, and blood pressure. The figure illustrates how higher LE8 scores are associated with lower mortality risk, particularly under more favorable SDOH conditions.

Abbreviations: SDOH, social determinants of health; LE8, Life’s Essential 8; BMI, body mass index; BP, blood pressure; CVD, cardiovascular disease; HDL-C, high-density lipoprotein cholesterol.