Living alone, social support, and relationship strain: links to epigenetic ageing

Social connections have been linked to a wide range of health outcomes; however, their role in the epigenetic processes underlying biological ageing is less well understood, particularly across different dimensions of social relationships. This study examined how structural, functional, and quality aspects of social connections are cross-sectionally associated with epigenetic ageing, using measures of both epigenetic age and pace of ageing.

Using data from Understanding Society, we applied doubly robust inverse-probability-weighted regression models to investigate the associations between living alone (structural indicator), social support (functional indicator), and relationship strain (quality indicator), and the second- and third-generation epigenetic clocks (PhenoAge, DunedinPoAm, and DunedinPACE). Covariates in both treatment and outcome models included age, age squared, sex, education, household income, employment status, living area, and area deprivation, with additional adjustment for cell composition in the outcome model. A series of sensitivity analyses were conducted to examine confounding, non-linear ageing processes, and sex differences.

In fully adjusted models (n=3,320), living alone was associated with higher epigenetic age as measured by the second-generation clock, but showed no association with pace of ageing as captured by third-generation clocks. Greater social support was associated with a slower pace of ageing, whereas greater relationship strain was associated with a faster pace of ageing. Sensitivity analyses are ongoing and will be presented in the talk.

By jointly examining different dimensions of social connections across both second- and third-generation clocks, these findings suggest that different aspects of social connections may have distinct biological correlates, with functional and quality aspects playing a particularly important role in shaping the pace of epigenetic ageing. Therefore, supporting individuals in maintaining and improving their social relationships could be a potential approach for slowing biological ageing.