DNA methylation is a process where methyl groups are added to DNA to influence gene expression, and which are critical for normal human development, defining cell identity, as well as for rejuvenation and reprogramming.Ā Highly accurate estimators of chronological age have been developed are known as epigenetic aging clocks, which can predict chronological age through development and across the lifespan (Horvath 2013, Horvath & Raj 2018).Ā
Increasingly these clocks are also being used as a measure of biological age as certain measures ā most notably GrimAge (Lu 2019, Li 2020), which is able to predict future morbidity and mortality risk.Ā GrimAge also performs well for predicting functional decline and onset of major age-related diseases, including heart disease, cancer onset, multi-modal measures of brain health, kidney disease, fatty liver, respiratory function, and more (Lu 2019, Hillary 2018, Hillary 2020, McCrory 2020). These peer reviewed and independent studies have also shown that it performs reliably across large diverse populations.Ā Ā
Many researchers conclude today that overall epigenetic clocks now represent the most robust measure of biological age (Li 2020, Jylhava et al 2017, Justice & Kritchevsky 2020).