New Study Shows Higher Lifetime Dementia Risk for Americans

New research suggests the risk of Americans developing dementia over a lifetime may be much higher than once thought. A new study predicts about one million Americans will likely develop the disease each year by 2060. That is about twice the number of people estimated in earlier studies.

The new finding is based on a large study involving a team from major U.S. medical centers and other research organizations. It recently appeared in the publication Nature Medicine. The study found that after age 55, people face up to a 42 percent chance of developing dementia, if they live long enough.

The research showed the risk of dementia is highest after age 75. But the good news is that there are steps people can take to reduce the risks. One of them is controlling high blood pressure and other conditions, such as diabetes or being severely overweight, meaning obese. Health experts advise everyone, even those in middle age, to take steps to avoid such problems.

Dr. Josef Coresh of NYU Langone Health was a lead writer of the study. He told The Associated Press, "All of our research suggests what you do in midlife really matters."

What is Dementia?

It can be quite common for older people to take longer to remember a name or where they placed certain objects. But research on dementia suggests it is not a normal part of aging. Rather, the disease is a progressive loss of memory, language and other cognitive abilities over time. Getting older is currently the biggest risk and the U.S. population is aging at a fast rate.

Dementia has many forms, the most common being Alzheimer's. Because the disease is linked to silent changes in the brain, signs or symptoms of dementia might not start showing until many years later. Other kinds include vascular dementia, when heart disease or small strokes limit blood flow to the brain. Many people also have mixed causes, meaning vascular problems could worsen existing dementia.

Dr. James Galvin is an Alzheimer's specialist at the University of Miami. He noted that aging by itself is "not a guarantee that someone will develop dementia." Galvin was not involved in the new study. But he said the latest findings on that support previous research.

Dementia risk by age

Earlier studies estimated about 14 percent of men and 23 percent of women would develop some form of dementia during their lifetime. Since women live longer than men, they are more likely to get it.

But the latest research examined more recent data from a U.S. study that followed the heart health and cognitive abilities of about 15,000 older adults from 1987 until 2020. In that group, the risk for dementia averaged 35 percent for men and 48 percent for women.

One reason for the different rates is that the group of people studied lived longer. The study shows how the risk changes with additional years of life. Only 4 percent of people developed dementia between the ages of 55 and 75. Coresh describes this difference as an important 20-year window for protecting brain health. For people surviving common health threats until 75, the dementia risk then jumped — to 20 percent by age 85 and 42 percent between the ages of 85 and 95.

Black Americans had a slightly higher risk, 44 percent, than white individuals at 41 percent.

Ways to help lower dementia risk

There are some health risks people cannot control. Besides age, people can inherit a gene version, or variant, called APOE4. This can raise the risk of getting Alzheimer's later in life.

But medical researchers have identified some things people can do to delay, or possibly even prevent developing dementia. The University of Miami’s Galvin advises people to exercise, avoid obesity and control blood pressure. He noted that, "What's good for your heart is good for your brain."

Stay socially and cognitively active, too, Galvin said. He urges people to try hearing aids if age brings hearing loss, which can create social isolation. He added, "There are things that we have control over, and those things I think would be really, really important to build a better brain as we age."