An epigenetic measurement of an individual's biologic age versus chronological age appears to function as a biomarker of cognitive function and health in older women, according to a study appearing this week in JAMA Network Open. Previous studies have linked age-related disease and mortality to epigenetic age, which is a composite measure of DNA methylation (DNAm) levels across specific cytosine-guanine dinucleotide sites that together form a single measure associated with chronological or phenotypic age. To further investigate, a team led by scientists from the University of California, San Diego, performed a secondary analysis of genome-wide DNAm data on around 1,800 older participants in the Women's Health Initiative. The researchers find that participants with increased epigenetic age acceleration (EAA) — the difference between epigenetic age and chronological age — were less likely to live to 90 years old with intact mobility and cognitive functioning. "Future studies could usefully focus on the potential for public health interventions to reduce EAA and associated disease burden while increasing longevity," they write.