Social isolation and loneliness moderate the association between uncorrected hearing impairment and cognitive aging across 18 years

Hearing impairment affects a growing number of older adults and is associated with worse cognitive aging outcomes. However, the mechanisms linking hearing impairment and cognition are complex, and the role of potential moderating factors remains underexplored. This study examined whether social isolation and loneliness profiles (e.g., non-isolated but lonely) help explain why some older individuals experience faster cognitive decline as their hearing worsens, while others do not. Using longitudinal data from waves 1 to 9 of the Survey of Health, Ageing, and Retirement in Europe (SHARE), we analysed 33,741 individuals (Mage = 61.4, SD = 8.6). Multilevel modelling revealed that both levels and linear and quadratic changes in hearing impairment predicted lower cognitive performance and steeper cognitive decline. Additionally, compared to those who were non-isolated and less lonely, those in the non-isolated but lonelier profile exhibited steeper declines in episodic memory, but not executive functions, with worsening hearing. These findings highlight key psychosocial factors contributing to cognitive decline in the context of hearing impairment, underscoring the importance of targeted social and health interventions to support cognitive health in older adults.