Résumé
This study aimed to examine the associations between subjective well-being (SWB) and risk of all-cause dementia, Alzheimer's disease (AD), and vascular dementia (VD). We adopted a multidimensional approach to SWB that included the level and breadth of SWB, the latter indicating the extent to which SWB spreads across life domains. Participants (N = 171,197; mean age = 56.78; SD = 8.16 years) were part of the UK Biobank and were followed up to 8.78 years. Domain-general and domain-specific SWB were measured by single items, and the breadth of SWB was indexed with a cumulative score of satisfaction across domains. Dementia incidence was ascertained through hospital and death records. Cox regression was used to examine the association between SWB indicators and risk of all-cause dementia, AD, and VD. General happiness, health and family satisfaction, and satisfaction breadth (satisfaction in multiple domains) were associated with lower risk of all-cause dementia. The associations held after accounting for socio-demographics, health, behavioral, and economic covariates, and depressive symptoms. Health satisfaction and the breadth of satisfaction were also associated with lower risk of AD and VD, with a pattern of slightly stronger associations for VD compared to AD. Some life domains (e.g., health) may be more fruitfully targeted to promote well-being and help protect against dementia, but it is also important to enhance well-being across multiple domains to maximize the protective effects.