Centenarians with high cognitive test scores may ward off dementia, decline

A cognitive test identified individuals aged 100 years or older who had high levels of cognitive performance, according to study findings published in JAMA Network Open.

Researchers posited that investigation of these individuals may reveal the mechanisms underlying resilience against cognitive decline risk factors.

“Dementia incidence increases exponentially with age, to an estimated 40% per year in individuals aged 100 years,” Nina Beker, MSc, of Alzheimer Center Amsterdam, and colleagues wrote. “Results from cross-sectional studies indicated that approximately 50% of centenarians show clear symptoms of dementia and that 25% of centenarians exhibit at least some symptoms of cognitive impairment, whereas approximately 25% are considered to be cognitively healthy. However, these number vary across studies, because it is difficult to define cognitive health in centenarians, in part because of their physical frailty, which hampers accurate cognitive assessment.”

To identify individuals who avoid cognitive decline until significantly older ages and to determine the prevalence of associated risk factors, the researchers analyzed data from the 100-plus Study. This prospective observational cohort study included community-based Dutch centenarians who were visited annually between 2013 and 2019 until participation was no longer possible or until death. Participants self-reported their cognitive health, which was confirmed by a proxy. The analysis included 340 centenarians, and researchers assessed their cognition using the Mini-Mental State Examination (MMSE). Specifically, they looked at the association of baseline cognition with cognitive trajectories and survivorship for 2 years or longer using linear mixed models, adjusted for education, age and sex. Furthermore, they investigated the prevalence of cardiovascular disease and apolipoprotein E (APOE) genotypes as risk factors for cognitive decline.

Median age at baseline was 100.5 years (range, 100-108.2), and 72.1% of participants were women. Results showed a maximum survival estimate plateau of 82% per year (95% CI, 77-87) across participants with scores of 26 to 30 points on the baseline MMSE (HR = 0.56; 95% CI, 0.42-0.75). The researchers noted that an MMSE score of 26 or higher was representative of both physical and cognitive health.

Seventy-nine centenarians were followed for at least 2 years, and those with baseline MMSE scores of less than 26 experienced a decline of 1.68 points per year (95% CI, 2.45 to 0.92) in MMSE score; however, centenarians with baseline MMSE scores of 26 or higher experienced a decline of 0.71 points per year (95% CI, 1.08 to 0.35). The researchers observed no changes among 73% of the centenarians with baseline MMSE scores of 26 or higher, and this lack of change often extended to ensuing years or death. This group is likely representative of less than 10% of Dutch centenarians, the researchers wrote. Approximately 19% of those in this group carried at least one APOE-epsilon 4 allele compared with approximately 6% of those with lower and/or declining cognitive performance.

“The identification of cognitive resilience in centenarians indicates that they may have factors associated with successful aging,” the researchers wrote. “The further investigation of genetic and downstream molecular constellations in blood and brain tissues from these centenarians may lead to novel insights in processes that maintain cognitive health during extreme longevity.” – by Joe Gramigna

Disclosure: Beker reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.