The joint association between race/ethnicity and education on all-cause mortality risk among US adults aged 25 years or older: A mediation analysis of telomere length

PURPOSE: Racial/ethnic inequities in mortality risk persist in the US, even after accounting for socioeconomic factors such as education. Telomere length (TL), a biomarker of aging, has been proposed as a potential mechanism underlying these inequities. This study examined the joint association of race/ethnicity and education with all-cause mortality and whether TL mediated this relationship. METHODS: We used data from the National Health and Nutrition Examination Survey (1999-2002) and 2019 Linked Mortality File (n = 6526; 2166 deaths). Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the joint race/ethnicity-education categories. Causal mediation analysis was used to examine the contribution of TL to this association. RESULTS: Among White adults, those with less than high school education (HS) had 2.26 times higher mortality rate (95% CI: 1.93, 2.65) than those with greater than HS. Blacks with greater than HS had 1.38 times higher mortality rate (95% CI: 1.04, 1.84) than Whites with greater than HS. No association was found between education and mortality among Mexican Americans. TL did not significantly mediate these relationships. CONCLUSIONS: Persistent differences across racial/ethnic groups with comparable education suggest that other factors may contribute to inequities in mortality risk.