Cognitive leisure and dementia risk: evidence beyond reverse causation.

BACKGROUND

Engagement in cognitive leisure activities (CLA) may reduce the risk of dementia, but findings are often challenged by reverse causation and unmeasured cognitive reserve.

OBJECTIVE

To examine the association between CLA and incident dementia whilst accounting for reverse causation and lifelong cognitive enrichment.

DESIGN

Prospective cohort study with a 12-year follow-up, including a 7-year exposure-outcome time lag.

SETTING

Community-dwelling older adults from the three-city study conducted in France.

SUBJECTS: A total of 3326 participants aged 65 and older, free of dementia at baseline and during the time-lag period.

METHODS

At baseline, participants reported frequency of engagement in five cognitively stimulating activities. A global CLA score was calculated and categorised into low, moderate, and high engagement. Incident dementia and Alzheimer's disease (AD) were ascertained during the 5-year follow-up. Delayed-entry Cox models with age as the time scale were used, adjusting for socio-demographic, health-related, and genetic factors including APOE ε4 and past occupational grade.

RESULTS

Compared to low CLA engagement, moderate and high engagement were associated with lower risk of dementia (hazard ratios [HR] = 0.50 [95% CI: 0.33-0.76] and 0.53 [0.35-0.80]) and AD (HR = 0.35 [0.20-0.59] and 0.45 [0.28-0.73]). Frequent engagement in crosswords and artistic activities showed the strongest independent associations with reduced dementia risk.

CONCLUSIONS

CLA in late life is associated with lower dementia risk, beyond the influence of cognitive reserve and reverse causation. Promoting such activities may be a valuable component of dementia prevention strategies in older adults.