Why the oldest-old is free of Alzheimer’s disease

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A team led by researchers from the University of California, Irvine has made an interesting discovery about the oldest-old people (those over 90) who have excellent cognitive abilities.

These individuals show similar brain pathology, or disease indicators, as Alzheimer’s patients.

However, they seem to have less brain pathology related to other neurodegenerative diseases, which can affect memory and thinking.

The findings were published in an article titled “Superior Global Cognition in Oldest-Old is Associated with Resistance to Neurodegenerative Pathologies: Results from the 90+ Study” in the Journal of Alzheimer’s Disease.

Key Findings from the Study

The researchers found that people aged 90+ with good memory and thinking skills tend to show similar levels of Alzheimer’s disease changes in their brains.

However, they seem to be less prone to other types of neurodegenerative changes, such as Lewy body disease, explains Roshni Biswas, a post-doctoral scholar involved in the study.

As age increases, so does the risk for cognitive problems, like Alzheimer’s, Lewy body disease, and other related dementias.

Over the last three decades, the number of people aged 90 and older in the U.S. has nearly tripled. This trend is expected to continue, with the number predicted to quadruple in the next 40 years.

Despite the rise in age, some people retain superior cognitive abilities, but there’s little data on the brain changes in these individuals.

The aim of the study was to look at the brain characteristics of people without cognitive impairment and understand their connection to superior cognitive skills in the 90+ group.

Significance of the Study

María M. Corrada, ScD, co-principal investigator of the study and professor in the Department of Neurology at UCI School of Medicine, highlighted the significance of these findings.

“Some individuals can maintain high levels of cognitive function well into advanced ages,” she noted.

“More research into the factors that enable these individuals to keep their cognitive function could provide insights into preserving cognitive health despite advanced age.”

The study involved analyzing autopsy data from 102 cognitively normal individuals who died at an average age of 97.6 years.

The researchers also used cognitive test scores from individuals taken between two to twelve months before death.

“In our future research, we will examine how lifestyle habits and health conditions are associated with superior cognition in individuals who are 90+ and the factors that contribute to maintaining stable cognitive function over time,” said Biswas.

The 90+ Study

The 90+ Study is a long-term study on aging and dementia that began in 2003. It focuses on studying the oldest-old population, which is the fastest growing age group in the United States.

With over 2,000 participants enrolled, it’s now one of the largest studies of its kind worldwide. The project has yielded important findings regarding cognitive function, health, and lifestyle habits in the oldest-old population.

If you care about brain health, please read studies about how unhealthy blood pressure increases your dementia risk, and vitamin B12 deficiency may increase risk of Alzheimer’s.

For more information about brain health, please see recent studies that cranberries could help boost memory, and food pyramid and activities could help prevent Alzheimer’s.

The study was published in the Journal of Alzheimer’s Disease.

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