Abstract:
Background: Dementia is a chronic neurodegenerative syndrome, with a progressive nature, and leads to deterioration in cognitive function by important damage to neurons. Dementia is currently the seventh leading cause of mortality and affects more than 55 million individuals worldwide. This study aim to collect existing data in the field of epigenetics to provide a new perspective on the impact of lifestyle on the incidence of dementia through epigenetic modification. The present study aimed to find possible links between dementia and epigenetic modification focusing on age accelerators through environmental factors.
Methods: Following the PRISMA guidelines, systematic searches of Medline, EMBASE, PsycINFO, Web of Science, Scopus, and the Cochrane Library conducted.
Results: Although, genetic variants have a deterministic role in the starting dementia process. But modifiable environmental and lifestyle risk factors have also been associated with dementia. Environmental factors alter epigenetic age or DNAm (DNA methylation) age. Intrinsic epigenetic age acceleration (IEAA), extrinsic epigenetic age acceleration (EEAA), age acceleration – AgeAccelPheno (based on PhenoAge) and, AgeAccelGrim (based on GrimAge) consider as novel epi-biomarkers to estimate epigenetic age. Number of risk factors such as smoking and poor physical activity for dementia have associated with age acceleration.
Conclusion: Conclusion: Individual, separated, and relatively small size studies demonstrated lifestyle habits and environmental factors are related to the epigenetic modifications resulting in changes in gene expression. Recognized age-accelerating DNA methylation sites, could be defined as new epi-biomarkers to measure the risk of early onset of determine. Further studies by analyses of separate dementia subtypes are required to investigate the potential association between DNA methylation-based measures of accelerated aging and dementia. Taking into consideration that epigenetic changes are reversible, so targeting lifestyle changes may be a promising strategy for the management of dementia.