An epigenetic clock produces an epigenetic age from a patient blood or tissue sample. These clocks are trained on data from many individuals at varying ages. When the measured epigenetic age is greater than chronological age, in other words that their biochemistry looks more like that of older people from the training data, this is referred to as epigenetic age acceleration, and is thought to represent a more rapid progression of degenerative aging. Numerous studies have correlated epigenetic age acceleration with risk of specific age-related conditions. Here, researchers correlate it with odds of survival to late life. The worse the epigenetic age acceleration, the worse the odds of survival.
To our knowledge, this cohort study is the first study examining the association between epigenetic age acceleration (EAA) and healthy longevity among older women. In this racially and ethnically diverse cohort of older women, increased EAA as measured by Horvath, Hannum, PhenoAge, and GrimAge clocks was associated with lower odds of survival to age 90 years with intact mobility. Results were similar when including intact cognitive functioning.
Among 1813 women, there were 464 women (mean age at baseline, 71.6 years) who survived to age 90 years with intact mobility and cognitive functioning, 420 women (mean age at baseline, 71.3 years) who survived to age 90 years without intact mobility and cognitive functioning, and 929 women (mean age at baseline, 70.2 years) who did not survive to age 90 years. Women who survived to age 90 years with intact mobility and cognitive function were healthier at baseline compared with women who survived without those outcomes or who did not survive to age 90 years. The odds of surviving to age 90 years with intact mobility were lower for every 1 standard deviation increase in EAA compared with those who did not survive to age 90 years as measured by Horvath (odds ratio 0.82), Hannum (odds ratio 0.67), PhenoAge (odds ratio 0.60), and GrimAge (odds ratio 0.68) clocks.
This cohort study's findings suggest that EAA may be a valid biomarker associated with healthy longevity among older women. Our results suggest that EAA may be used for risk stratification and risk estimation for future survival with intact mobility and cognitive functioning within populations. Future studies could usefully focus on the potential for public health interventions to reduce EAA and associated disease burden while increasing longevity.