Social determinants of health and life expectancy in US adults.

INTRODUCTION

Individual unfavorable social determinants of health (SDoH) negatively affect health outcomes, yet the combined impact of multiple SDoH on life expectancy is not well understood.

METHODS

We analyzed data from a nationally representative sample of US adults aged ≥18 years in NHANES (1999–2018) to examine associations between unfavorable SDoH—both individually and in combination—and life expectancy.

RESULTS

Among 45,516 participants (mean age 47.7 years; 51.4% women) with a median follow-up of 9.4 years, 6,164 deaths occurred. Four key SDoH—employment, family income, education, and marital status—were individually associated with shorter life expectancy at age 50: unemployment (−4.2 years, 95% CI 3.9–4.6), low income (−3.5, 3.1–3.9), low education (−3.1, 2.7–3.4), and unmarried status (−2.4, 2.1–2.8). Among 16 combined SDoH profiles, participants who were unemployed, low-educated, and unmarried lost 10.8 years compared with the most favorable profile. Notably, education had the largest individual impact, but its effect diminished when combined with other adverse SDoH; well-educated individuals with multiple unfavorable SDoH lost more life years than less-educated counterparts (7.2 vs. 4.9 years).

CONCLUSIONS

In this nationally representative cohort, four key SDoH strongly influenced life expectancy. Multiple adverse SDoH had additive effects, and the impact of education was context-dependent, emphasizing the importance of considering combined social risk in public health strategies.