|Title||Chronic loneliness-by-epigenetic age effects on dementia risk in late adulthood|
|Publication Type||Journal Article|
|Year of Publication||2021|
|Authors||Lynch, ME, Beam, CR|
|Journal||Alzheimer's & Dementia|
|Keywords||Biological age, dementia risk, DNA Methylation, Loneliness|
Background Over the last 10 years, numerous studies have been published reporting a small but significant correlation between loneliness and dementia risk. To date, few studies have tested mechanisms that mediate the longitudinal association between loneliness and dementia. DNA methylation may be one variable that explains this association, as when combined with other biomarkers, quantifies whether people’s biological age is more (or less) advanced than their chronological age. The purpose of this study is to test whether epigenetic age moderates the longitudinal trajectory of loneliness on dementia risk. Method The sample was drawn from the three waves of the Health and Retirement Study (n = 268, mean age = 69) collected four years apart from 2008-2016. Loneliness scores were composed using with 11 items of the UCLA Loneliness Questionnaire. Dementia risk was quantified according to Langa-Weir’s approach that uses the modified Telephone Interview for Cognitive Status. Epigenetic age is quantified by DNAm PhenoAge (Levine et al., 2015.). Ordinary least squares regression was used to test the interaction effect of DNAm PhenoAge and loneliness on dementia risk. Result A significant interaction effect between DNAmPhenoAge and longitudinal loneliness on dementia risk was found (F(7,268) = 6.98 , p < 0.001; adjusted R2 =.13). Effects of DNAm PhenoAge were greater in those with higher levels of loneliness over time, suggesting that effects of loneliness on dementia risk depend on epigenetic age. Conclusion Study results suggest that the longitudinal association between loneliness and dementia risk depends on epigenetic age. One implication of the current results is that the epigenome may be a promising area of study for understanding the processes through which loneliness increases dementia risk.