Behaviors that enhance cognitive reserve or improve certain other psychosocial and health factors may offer a degree of protection from the cognitive decline associated with the APOE ε4 allele, according to research published in the March issue of JAMA Neurology.
Allison R. Kaup, PhD, of the Sierra Pacific Mental Illness Research, Education, and Clinical Center at the San Francisco Veterans Affairs Medical Center, and her associates analyzed data collected in the prospective Health, Aging, and Body Composition study to identify factors that may promote cognitive resilience in carriers of the APOE ε4 allele. The study examined aging-related health in 3,075 older adults residing in Pittsburgh or Memphis between 1997 and 1998. These study participants, who were between ages 69 and 80 at baseline, had repeated cognitive testing during 11 years of follow-up. A subset of 670 individuals were APOE ε4 carriers.
As expected, APOE ε4 carriers had greater cognitive decline over time than noncarriers did. A subset of APOE ε4 carriers, however, showed high retention of cognitive status in comparison with demographically similar noncarriers. Among Caucasian carriers, the factors that strongly predicted cognitive resilience were, in order of importance, an absence of recent negative life events, higher literacy level, older age, higher education level, and more time spent reading. Among African American carriers, the factors that most strongly predicted cognitive resilience were higher literacy level, higher education level, female sex, and absence of diabetes mellitus.
The reasons why some predictors differed by race aren’t yet understood. The investigators analyzed the two races separately because the prevalence of APOE ε4 differs by race, as does the gene’s impact. APOE ε4 occurs more frequently among African Americans than among Caucasians, and the gene’s deleterious effects on cognition are weaker in African Americans than in Caucasians.
The current findings “raise the possibility that interventions targeting the modifiable factors among these predictors could help promote cognitive resilience in APOE ε4 carriers,” said Dr. Kaup. For example, promoting cognitive reserve would likely be protective for both races. In addition, Caucasians would likely benefit most from stress reduction or stress management, while African Americans would likely benefit most from prevention or close management of diabetes.
—Mary Ann Moon