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Studies find onset of Alzheimer’s disease decades before problems begin

Posted on 08/15/19

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This year’s Facts and Figures report from the Alzheimer’s Association estimates that 5.8 million Americans are living with dementia due to Alzheimer’s disease–a number expected to grow steeply in coming decades as Baby Boomers age. The report also lists and defines the stages of Alzheimer’s disease, one of which might be unfamiliar to you.

The last, most severe, and most recognizable stage of Alzheimer’s disease is “dementia due to Alzheimer’s disease.” This diagnosis is given when Alzheimer’s disease has advanced enough to cause cognitive deficits serious enough to render a person incapable of caring for themselves. Dementia due to Alzheimer’s disease is preceded by a milder form of cognitive decline, called “mild cognitive impairment (MCI) due to Alzheimer’s disease.” Individuals with MCI notice problems with memory and thinking but these problems are not serious enough to prevent them from independently carrying out their activities of daily living. MCI may or may not progress to dementia, but if Alzheimer’s disease is the cause of MCI, progression is likely.

The Facts and Figures report also lists a stage of Alzheimer’s disease that precedes MCI. This stage has been named “Preclinical Alzheimer’s disease.” During this stage individuals have changes in the brain (e.g. accumulation of amyloid plaques, tau tangles, inflammation, and poor glucose sensitivity) that are characteristic of Alzheimer’s disease, but the damage to neurons is not extensive enough to cause cognitive symptoms. It is this stage of Alzheimer’s disease that researchers have targeted for intervention, both through drug development and testing, and through lifestyle and health modifications with the purpose of delaying the onset of dementia far enough into the future to give an individual a dementia-free life.

The brain demonstrates remarkable ability to function despite the presence of disease. A recent study reports Alzheimer’s pathology developing 34 years before dementia onset. What are some ways to potentially delay the onset of dementia in the presence of preclinical Alzheimer’s disease?

· Regular moderate-level aerobic exercise, like brisk walking for 40 minutes 3 times per week has been shown to delay age-expected neurodegeneration.
· Adequate healthy deep sleep has been shown to help flush toxic proteins like amyloid from the brain.
· Eating a low-inflammatory diet like the Mediterranean or Mind diet may protect the brain (and body) from inflammation and oxidative stress.
· Lifelong learning and maintaining an active social life may give the brain increased ability to thrive in the presence of disease.
· Managing and treating diabetes and hypertension can further reduce risk of MCI and dementia. It has been estimated delaying the onset of dementia by 5 years would lead to a 50% reduction in the prevalence of dementia due to Alzheimer’s disease.

To learn more about the risk factors for Alzheimer’s disease and dementia, or for an appointment with a neurologists specializing in brain health and dementia prevention, visit

This story is provided by AARP Illinois. Visit the AARP Illinois page for more news, events, and programs affecting retirement, health care, and more.

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