Alzheimer’s disease is the most common dementia, impacting over 5 million Americans. Although the disease was first described by Dr. Alzheimer in the early 1900s, scientists are still trying to understand its causes. Here are some of today’s leading theories:


In 1900, the average life expectancy in the United States was 47. Today people live well into their 80’s and 90’s. This is good news for most of us and many seniors are enjoying an active, engaged life. However, one downside of a long life is that aging increases your risk for Alzheimer’s disease – 15% of people over 65 have Alzheimer’s disease; 40% of people over 85. Despite these frightening percentages, most researchers don’t think that Alzheimer’s disease is a “normal” part of aging. Researchers remain hopeful that we will develop strategies to delay the onset of Alzheimer’s or prevent it altogether.

Family history

The consensus among researchers is that if you have one or more parent or close family member with Alzheimer’s disease, you are generally considered to be at greater risk for developing the disease. One gene in particular called ApoE4 increases your likelihood of getting Alzheimer’s disease. Like all risk factors, a family history may or may not lead to the development of the disease.

Lifestyle factors

Some lifestyles may be very unfriendly to the brain and increase the risk of Alzheimer’s disease. For example, individuals who sustain concussions or head injury (through sports, work or accidents) have a greater risk of getting Alzheimer’s. Positive lifestyle factors that may prevent Alzheimer’s or delay the onset include exercise (break a sweat at least once a day), a healthy diet rich in antioxidants, socialization, treating depression, lifelong learning (“use it or lose it”) and avoiding tobacco use.

The Alzheimer’s Association has described the suspected links between heart health and brain health. The Association argues that “what is good for the heart is good for the head.” We may not know if a low fat, heart friendly diet will ultimately prevent Alzheimer’s, but it certainly can prevent stroke, another enemy of the brain.

Plaques and Tangles

Two areas of ongoing research include studying the buildup of plaques and tangles in the brain. Plaque consists of the protein beta amyloid that accumulates in the spaces between nerve cells. Tangles are the twisted fibers of another protein tau (rhymes with “how”) that accumulates inside nerve cells.

These proteins most likely block the ability of the cells to communicate, leading to cell death. This cellular death ravages the brain and causes the progressive symptoms of Alzheimer’s disease.

Much of the research to date on potential medications for Alzheimer’s has looked at ways to prevent the buildup of plaques and tangles in the brain. Unfortunately, there have been a number of very high profile failures and disappointments with promising drugs. Many scientists are now looking at other mechanisms besides attacking plaques and tangles, for example, looking at inflammation in the brain as a possible trigger for Alzheimer’s disease

Within the field of Alzheimer’s research, there is much optimism, but also a sobering recognition that there is still much to be accomplished. The good news is that our field of knowledge about Alzheimer’s disease is expanding rapidly. New tools such as powerful scanners can look inside of the brain and now even identify amyloid plaques. There is also a world wide effort underway with significant coordination of research between scientists and universities.

The Alzheimer’s Association points out that 90% of what we’ve learned about Alzheimer’s disease has been discovered in the last 15 years. Let’s hope that the next 15 years leads to the breakthroughs we need to help Alzheimer’s disease itself become a “distant memory.”

Alzheimer’s Association

Preventing Alzheimer's & Other Dementias

Laurie Owen from Home Instead Senior Care and Dr. Jane Potter from the University of Nebraska Medical Center discuss how to prevent Alzheimer's disease and other dementias.

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