DNA Methylation–Based Measures of Biological Aging

Aging is associated with profound changes in DNA methylation. Recent studies have used DNA methylation to build very accurate age predictors, also named “epigenetic clocks,” that deviate from chronological age by only a few years. The individual-specific deviation from chronological age—represented by the residual from a regression of predicted age on chronological age—has been interpreted as a biomarker of biological aging and referred to as “age acceleration” or “epigenetic aging.” Numerous studies have investigated such measures of biological aging based on DNA methylation and have found them to be associated with mortality, disease, and risk factors for disease. Although the biological significance of age acceleration measures is not yet fully characterized, they represent a promising tool for epidemiologists and clinicians to study health. Other attempts to characterize how age-associated methylation changes relate to health are likely to emerge in the near future.