In analyses of the epigenetic clocks in relation to clinical and genetic factors, including dementia and AD dementia diagnoses, cognition and memory scores, and APOE genotype, it was found that older epigenetic ages based on the Hannum, Horvath, and PhenoAge clocks were not associated with increased likelihood of AD dementia, global cognitive decline over time, or specific cognitive function declines. The gene discussed is APOE; the disease is dementia.