The Women’s Health Initiative Memory Study (WHIMS) has provided valuable insights into the role of epigenetic clocks in predicting longevity. This study examined a cohort of 5,844 women to assess the relationship between epigenetic age acceleration (EAA) and survival to age 90, with a focus on cognitive health.
Background
Epigenetic clocks are biological markers that estimate an individual’s biological age based on DNA methylation patterns. Understanding whether these clocks can predict exceptional longevity, particularly in the context of cognitive health, is crucial for developing interventions aimed at promoting healthy aging.
Methods
The study analyzed data from the WHIMS, where 15 different epigenetic clocks were measured at baseline (1996-1999). Longevity outcomes were categorized into three groups: survival to age 90 with preserved cognition, survival to age 90 with cognitive impairment, and death before age 90. Logistic regression models were employed to explore the associations between the epigenetic clocks and longevity outcomes, adjusting for various covariates.
Results
The findings indicated that each standard deviation increase in EAA for the first-generation clocks was linked to a 7%-18% reduction in the odds of surviving to age 90 compared to earlier death. Notably, stronger associations were observed for second- and third-generation clocks, such as AgeAccelGrim2 (odds ratio [OR] = 0.66), PCGrimAge (OR = 0.64), PCPhenoAge (OR = 0.73), and DunedinPACE (OR = 0.77). However, none of the clocks demonstrated a stronger association with survival to age 90 with preserved cognition compared to survival with cognitive impairment.
Conclusions
While all epigenetic clocks examined were associated with exceptional longevity, none were able to differentiate between long survival with or without preserved cognitive function. This highlights the need for further research to develop epigenetic clocks that can accurately predict cognitive healthspan alongside longevity.
What this study does not show
This study does not establish a causal relationship between epigenetic age acceleration and cognitive health, nor does it provide evidence that specific interventions based on epigenetic clock results can enhance cognitive longevity.
Evidence scorecard
- Analytic validity: Established
- Clinical validity: Partial
- Clinical utility: Not established
The evidence class is primary research involving human subjects.