The Association of Life's Crucial 9, Socioeconomic Status, and Social Isolation With Dementia.

OBJECTIVE

To investigate the association between Life's Crucial 9 (LC9) and dementia, and the mediating and interaction effects of socioeconomic status or social isolation with LC9, as well as their joint association on dementia.

METHODS

LC9 included diet, physical activity, body mass index, sleep duration, tobacco exposure, blood lipids, blood pressure, blood glucose, and psychological health. Socioeconomic status was derived from education, income, and employment status. Social isolation was based on household cohabitants, friend/family visit frequency, and weekly social activities. Cox proportional hazard models were performed to estimate the association of LC9 with dementia.

RESULTS

Our analysis included 336,394 UK Biobank individuals. Compared with high LC9 category, the hazard ratio (95% confidence interval) with low LC9 category was 2.12 (1.72-2.62) for all-cause dementia. The association between LC9 and dementia was partially mediated by socioeconomic status or social isolation. A significant additive interaction was observed between LC9 and socioeconomic status on all-cause dementia (p <0.05). Participants with low LC9 category, low socioeconomic status and social isolation had the highest risk of dementia compared with those with high LC9 category, high socioeconomic status and no social isolation (HR: 3.35, 95% CI: 2.79-4.01).

CONCLUSIONS

The low LC9 category was associated with a higher risk of dementia, and socioeconomic status or social isolation mediated a small proportion of this association. These results feature the importance of preserving an ideal LC9 as a potential prevention approach for dementia and emphasize the benefits of simultaneous and comprehensive intervention strategies in decreasing dementia risk.