Race/Ethnicity, Education, and All-Cause Mortality in US Adults: Mediation by Telomere Length

Abstract Background Racial/ethnic inequities in mortality risk are pervasive in the United States even after controlling for socioeconomic status indicators such as educational attainment. Although the mechanisms underlying these inequities remain unclear, telomere length (TL) has emerged as a potential mediator. We aimed to investigate the joint association of race/ethnicity and education with all-cause mortality risk, and the contribution of TL to this relationship. Methods We used data from the U.S. National Health and Nutrition Examination Survey, 1999 to 2002, and 2019 Linked Mortality File (n = 6,526 non-institutionalized adults aged 25 years or older, including 2,166 deaths), a retrospective cohort study with a follow-up period to December 31, 2019. Cox proportional hazards regression and causal mediation analysis were used to address these aims. We reported hazard ratios (HR) and 95 % confidence intervals (CI). Furthermore, for the mediation analysis, we reported the total, direct, and indirect effects measured as HR and 95 % CI. Results After adjusting for age and sex, among White individuals, those with less than a high school education had a 2.26 times higher (95% CI: 1.93, 2.65) rate of all-cause mortality compared to those with some college or higher education. When compared with White adults with at least a college degree, Black adults with at least a college degree had a 1.38 higher rate of dying (95% CI: 1.04, 1.84). There was no significant joint association of race/ethnicity and education on all-cause mortality in Mexican Americans. In the mediation analysis, TL did not significantly contribute to the joint association of race/ethnicity and education with all-cause mortality risk. Discussion These findings underscore the need for a better understanding of the joint relationship of race/ethnicity and education on mortality risk inequities and their potential mechanisms to improve population health ultimately. Key messages • Lower educational attainment was associated with higher mortality rates among White individuals, disparities persisted among the Black population, despite higher education levels. • Our analysis did not find a significant mediation effect of telomere length on the joint effect of race/ethnicity and education-mortality relationship.