Researchers have found that biological aging, as measured by DNA methylation-based epigenetic clocks, may play a significant role in explaining why individuals from different socioeconomic and demographic backgrounds experience varying life expectancies.

The findings, published in a recent study using data from the National Health and Nutrition Examination Survey (NHANES) 1999–2002, examined how factors such as race, ethnicity, education, income, and occupation are associated with mortality risk. The research explored whether biological aging markers could help explain these long-observed health disparities.

Socioeconomic status has long been linked to differences in life expectancy. Individuals with higher levels of education, income, and occupational status generally live longer than those facing economic and social disadvantages. Researchers have sought to understand the biological mechanisms underlying these disparities.

The study focused on DNA methylation clocks, advanced biomarkers that estimate biological aging by analyzing patterns of chemical modifications to DNA. Among the tools evaluated were the GrimAge2 clock and the Dunedin Pace of Aging Measure (DunedinPoAm), both of which have been developed to assess aging-related health risks.

Results showed that epigenetic aging measures accounted for a substantial portion of mortality differences across socioeconomic groups. GrimAge2 explained approximately 21 percent of the mortality gap between individuals with a high school diploma and those with a college degree or higher. The measure accounted for as much as 52 percent of the mortality difference between workers in high-skilled blue-collar occupations and those employed in professional or white-collar positions.

Similarly, the DunedinPoAm measure explained 11 percent of the mortality disparity between high school graduates and college-educated individuals, as well as 28 percent of the mortality difference observed between Hispanic and White participants.

Researchers noted that these epigenetic measures often demonstrated stronger explanatory power than traditional clinical biomarkers, suggesting that biological aging processes may serve as important pathways through which social and economic conditions influence long-term health outcomes.

The findings contribute to a growing body of research investigating biological age and its relationship to health and longevity. While scientists have yet to establish a universally accepted method for measuring biological age in individuals, epigenetic clocks are increasingly being studied as promising tools for understanding aging and mortality risk at the population level.

Researchers believe that continued investigation into biological aging markers could provide valuable insights into the mechanisms driving health inequities and help inform future strategies aimed at reducing disparities in longevity and overall health outcomes.