People experiencing social disadvantage tend to show faster biological aging, and this association was strongest when using the newest generation of epigenetic clocks.
This is according to a study — “Social determinants of health and epigenetic clocks: a systematic review and meta-analysis of 140 studies” by Y. E. Willems, A. D. Rezaki, M. Aikins, A. Bahl, Q. Wu, D. W. Belsky, and L. Raffington — that was published in Nature Human Behaviour.
The study synthesizes findings from 1,065 effect sizes across 140 studies involving 65,919 participants aged from birth to 86 years old. By summarizing results across many studies, the researchers were able to produce the most comprehensive assessment to date of how social conditions relate to epigenetic measures of biological aging.
Key findings
Social disadvantage accelerates biological aging: synthesizing results across 140 studies and nearly 66,000 individuals, lower socioeconomic status and marginalized racial or ethnic identities are consistently linked to faster biological aging as measured in the epigenome.
Not all epigenetic clocks are equal: Newer epigenetic measures—which capture how fast the body is aging—are more sensitive to social inequality than older clocks designed to estimate chronological age.
- The effects start early in life: Evidence of accelerated biological aging associated with social disadvantage is already visible in children, indicating that social inequality can shape biology from a young age.
Social inequality, such as poverty and racism, are related to biological aging measured in the epigenome, also known as “epigenetic clocks”. Epigenetic clocks analyze patterns of chemical marks on DNA to estimate a person’s biological age or the rate at which their body is aging. These tools are increasingly used by scientists to study how environmental exposures, lifestyle, and social conditions affect health across the life course.
Previous individual studies have shown that epigenetic clocks are sensitive to socioeconomic and racial or ethnic disparities. However, because multiple types of epigenetic clocks exist, it has remained unclear which measures best capture the effects of social determinants of health, at which stages of life socioeconomic exposures most affect epigenetic aging, and whether associations differ by sex or by technical factors such as the tissue in which epigenetic data are collected.
This study integrates findings across many independent studies offering a comprehensive test of whether these associations are consistent and robust.
Newer biological aging measures are most sensitive to social conditions
The study reveals a robust pattern: people experiencing social disadvantage tend to show faster biological aging, and this association was strongest when using the newest generation of epigenetic clocks.
First-generation clocks — designed primarily to estimate chronological age — are weakly associated with socioeconomic conditions. In contrast, second-generation clocks, which reflect health and mortality risk, and third-generation clocks, which measure the pace of aging, show substantially stronger associations with socioeconomic conditions.
Evidence across the lifespan
The study also indicates that social inequality influences biological aging from early in life: children growing up in lower socioeconomic circumstances already show signs of faster biological aging when measured using newer epigenetic clocks. The study further finds that adults who grew up in disadvantaged families tend to age faster biologically later in life, even decades after childhood exposures.
The researchers also examined racial and ethnic disparities in biological aging. In US-based studies included in the analys hey Siriis, Black participants show faster biological aging than white participants when measured with second- and third-generation clocks. Differences between Latinx and white participants are also observed, though somewhat smaller.
Implications for health research and interventions
The results help clarify which epigenetic clocks are most useful for studying how social and environmental conditions influence biological aging. The team notes that these tools may also help scientists evaluate whether interventions—such as poverty reduction programs, education policies, or health interventions—can slow biological aging and improve long-term health in the future.
