Superagers
Even at an advanced age, superagers have the memory of someone 20 or 30 years their junior. But why is that? A new study shows that in superagers, age-related atrophy of the gray matter, especially in the areas responsible for memory, develops much more slowly than in normal older adults. However, the study also emphasizes the importance of physical and mental fitness for a healthy aging process.
"One of the most important unanswered questions with regard to superagers is, 'Are they resistant to age-related memory loss, or do they have coping mechanisms that allow them to better offset this memory loss?' " wrote Marta Garo-Pascual, a PhD candidate at the Autonomous University of Madrid, Spain, and colleagues in the Lancet Healthy Longevity. "Our results indicate that superagers are resistant to these processes."
Six Years' Monitoring
From a cohort of older adults who had participated in a study aiming to identify early indicators of Alzheimer’s disease, the research group chose 64 superagers and 55 normal senior citizens. The latter served as the control group. While the superagers performed just as well in a memory test as people 30 years their junior, the control group’s performance was in line with their age and level of education.
All the study participants were over age 79 years. Both the group of superagers and the control group included more females than males. On average, they were monitored for 6 years. During this period, a checkup was scheduled annually with an MRI examination, clinical tests, blood tests, and documentation of lifestyle factors.
For Alessandro Cellerino, PhD, of the Leibniz Institute on Aging–Fritz Lipmann Institute in Jena, Germany, this is the most crucial aspect of the study. "Even before this study, we knew that superagers demonstrated less atrophy in certain areas of the brain, but this was always only ever based on a single measurement."
Memory Centers Protected
The MRI examinations confirmed that in superagers, gray matter atrophy in the regions responsible for memory (such as the medial temporal lobe and cholinergic forebrain), as well in regions important for movement (such as the motor thalamus), was less pronounced. In addition, the volume of gray matter in these regions, especially in the medial temporal lobe, decreased much more slowly in the superagers than in the control subjects over the study period.
Garo-Pascual and her team used a machine-learning algorithm to differentiate between superagers and normal older adults. From the 89 demographic, lifestyle, and clinical factors entered into the algorithm, two were the most important for the classification: the ability to move and mental health.
Mobility and Mental Health
Clinical tests such as the Timed Up-and-Go Test and the Finger Tapping Test revealed that superagers can be distinguished from the normally aging control subjects with regard to their mobility and fine motor skills. Their physical condition was better, although they, by their own admission, did not move any more than the control subjects in day-to-day life. According to Cellerino, this finding confirms that physical activity is paramount for cognitive function. "These people were over 80 years old — the fact that there was not much difference between their levels of activity is not surprising. Much more relevant is the question of how you get there — i.e., how active you are at the ages of 40, 50 or even 60 years old," he stressed.
Remaining Active Is Important
As a matter of fact, the superagers indicated that generally they had been more active than the control subjects during their middle years. "Attempting to stay physically fit is essential; even if it just means going for a walk or taking the stairs," said Cellerino.
On average, the superagers also fared much better in tests on physical health than the control subjects. They suffered significantly less from depression or anxiety disorders. "Earlier studies suggest that depression and anxiety disorders may influence performance in memory tests across all ages and that they are risk factors for developing dementia," said Cellerino.
To avoid mental health issues in later life, gerontologist Cellerino recommended remaining socially engaged and involved. "Depression and anxiety are commonly also a consequence of social isolation," he underlined.
Potential Genetic Differences
Blood sample analyses demonstrated that the superagers exhibited lower concentrations of biomarkers for neurodegenerative diseases than the control group did. In contrast, there was no difference between the two groups in the prevalence of the APOE e4 allele, one of the most important genetic risk factors for Alzheimer’s disease. Nevertheless, Garo-Pascual and her team of researchers assume that genetics also play a role. They found that, despite 89 variables employed, the algorithm used could only distinguish superagers from normal older adults 66% of the time. This suggests that additional factors must be in play, such as genetic differences.
Body and Mind
Since this is an observational study, whether the determined factors have a direct effect on super-aging cannot be ascertained, the authors wrote. However, the results are consistent with earlier findings.
"Regarding the management of old age, we actually haven’t learned anything more than what we already knew. But it does confirm that physical and mental function are closely entwined and that we must maintain both to age healthily," Cellerino concluded.
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