The association between activities and cognitive health: Stratified analysis by APOE ε4 status

Background
Despite the growing evidence on the modifiable and genetic factors associated with cognitive health, little is known about the role of the apolipoprotein E (APOE) gene ε4 allele in the associations between productive or leisure activities and cognitive health.
Objective
This study fills a gap of knowledge by examining the associations among employment, civic engagement, and leisure activities and cognitive health by the presence of APOE ε4 allele, an established risk factor of Alzheimer's disease (AD).
Methods
Using pooled data from the Health and Retirement Study (HRS) Psychosocial and Lifestyle Questionnaires (2010–2016) and the HRS data on APOE ε4 alleles, linear regression models with a lagged dependent variable were performed to examine associations between productive or leisure activities and cognitive functioning at the follow-up time point, as well as the role of APOE ε4 in these associations.
Results
Among all participants, employment, low or high-intensity volunteering, and cognitive/social leisure activities were associated with higher levels of cognitive functioning. The presence of at least one ε4 allele was related to poorer cognitive functioning at the follow-up time point. Among people without the APOE ε4 allele, employment, high-intensity volunteering, and cognitive/social leisure activities were significantly associated with cognitive functioning. Among people with at least one APOE ε4 allele, low-intensity volunteering and cognitive/physical leisure activities were significantly associated with better cognitive functioning.
Conclusions
We found that employment, civic engagement, and leisure activities all contribute to cognitive health, although the benefits may be restricted to low-intensity volunteering and cognitive/physical leisure activities among individuals with at least one APOE ε4 allele, who are known to be inherently at a greater risk of AD, highlighting an avenue to a relatively easily implementable strategy to promote cognitive health in this subpopulation.