Background Repetitive head impacts in former contact sport athletes are associated with cognitive impairment, accelerated cerebral atrophy and risk of neurodegenerative disease. Epigenetic clocks derived from age-associated DNA methylation (DNAm) profiles may capture accelerated biological ageing in neurodegenerative conditions; however, their application in former athletes remains unexplored. Here we aim to explore the application of epigenetic clocks as a measure of accelerated biological ageing in a cohort of former athletes. Methods In 126 former athletes (96% male; mean age: 54.5±14.4 years; mean concussions: 6.8±6.7), we examined associations of brain volumes, plasma neurofilament light levels and cognitive/behavioural scores with DNAmAge-acceleration, AgeAccelResidual and DNAmFitAge-acceleration. Results We only found an association between the number of concussions and DNAmFitAge-acceleration (p=0.003, B=0.46, R²=0.063), indicating that every two additional concussions were associated with a 5-year increase in DNAmFitAge-acceleration. There was also a trend towards an association between years of play and DNAmAge-acceleration in older athletes. Conclusions These preliminary findings suggest that specific epigenetic clock measures may serve as early markers of biological ageing related to repetitive head impacts.
Tang et al. (Mon,) studied this question.