Association of Epigenetic Age Acceleration With Incident Mild Cognitive Impairment and Dementia Among Older Women

Abstract Background Epigenetic age acceleration (AgeAccel), which indicates faster biological aging relative to chronological age, has been associated with lower cognitive function. However, the association of AgeAccel with mild cognitive impairment (MCI) or dementia is not well-understood. We examined associations of 4 AgeAccel measures with incident MCI and dementia. Methods This prospective analysis included 578 older women from the Women’s Health Initiative Memory Study selected for a case–cohort study of coronary heart disease (CHD). Women were free of CHD and cognitive impairment at baseline. Associations of AgeAccel measures (intrinsic AgeAccel [IEAA], extrinsic AgeAccel [EEAA], AgeAccelPheno, and AgeAccelGrim) with risks for incident adjudicated diagnoses of MCI and dementia overall and stratified by incident CHD status were evaluated. Results IEAA was not significantly associated with MCI (HR, 1.23; 95% CI, 0.99–1.53), dementia (HR, 1.10; 95% CI, 0.88–1.38), or cognitive impairment (HR, 1.18; 95% CI, 0.99–1.40). In stratified analysis by incident CHD status, there was a 39% (HR, 1.39; 95% CI, 1.07–1.81) significantly higher risk of MCI for every 5-year increase in IEAA among women who developed CHD during follow-up. Other AgeAccel measures were not significantly associated with MCI or dementia. Conclusions IEAA was not significantly associated with cognitive impairment overall but was associated with impairment among women who developed CHD. Larger studies designed to examine associations of AgeAccel with cognitive impairment are needed, including exploration of whether associations are stronger in the setting of underlying vascular pathologies.