Dementia in Your 40s and 50s—Early Onset Risks and Causes
It’s rare, but a disease linked with old age sometimes strikes during the prime of life. Find out what's known about signs of dementia in your 40s or 50s.
When you reach middle age, you're mostly focused on your career and family—not worrying about a disease associated with old age. But while dementia is much more common among seniors, some people do see signs of dementia in their 50s or earlier, known as early onset Alzheimer's or dementia.
When Dementia Comes Early
"Early onset Alzheimer's disease strikes people younger than 65—often in their 40s and 50s—and currently impacts about 200,000 Americans," says Rebecca Edelmayer, PhD, director of scientific engagement with the Alzheimer's Association.
That number represents a small percentage of the people who currently have Alzheimer's disease, estimated to be about 5 percent of all Alzheimer's cases, according to Matt Huentelman, PhD, a professor in the neurogenomics division of the Translational Genomics Research Institute (TGen), which is based in Arizona. "However, the numbers are growing as we improve our ability to diagnose dementia earlier."
The problem, says Edelmayer, is that "doctors do not understand why most cases of early onset Alzheimer's appear at such a young age."
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Risk Is Not Well Understood
It's not entirely clear whether early onset dementia is inherited. The Alzheimer's Society says that some people inherit Alzheimer's and show symptoms in their 30s, 40s or 50s, based on mutations in three specific genes. But it's rare, affecting less than 1 percent of all cases. The earlier symptoms begin, the more likely the cause is genetic.
Despite the rarity of that genetic form of dementia, Huentelman says that more than half of all people with early onset Alzheimer's do have some history of dementia in their family. That would suggest a strong genetic component to early onset risk, he says, even if the genetic underpinnings of early onset Alzheimer's remain "largely unexplained and under intense investigation."
One known risk factor is that Down syndrome and other learning disabilities can lead to dementia at an earlier age.
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Early Dementia Takes Many Forms
Early onset dementia can develop in different ways, and doesn't always mean a diagnosis of Alzheimer's. For instance, vascular dementia can develop when there's insufficient blood supply to the brain. This can affect younger people who struggle with diabetes or heart disease, and accounts for about 15 percent of younger dementia cases, according to the Alzheimer's Society.
In some cases, about 10 to 15 percent of the time, early onset dementia arises because of brain damage in the frontal or side lobes of the brain, known as frontotemporal dementia. This type of dementia is actually much more likely to affect young people than seniors.
According to the Alzheimer's Society, if signs of dementia develop as early as your 50s, it could also be due to the buildup of tiny protein deposits in the brain, known as Lewy bodies.
Alcoholism also raises the risk for a form of brain damage that can lead to youthful dementia.
Age Can Affect Type of Dementia
The Alzheimer's Society notes that across all ages, the disease shares similar roots in that proteins slowly build up to form what are called "plaques" and "tangles" in the brain.
But there are some major differences when it comes to the age of the person affected. About a third of younger people with Alzheimer's develop an atypical form of the disease, one that's only seen among 5 percent of older patients. And while memory loss is usually the first symptom for seniors with Alzheimer's, that's generally not the case for young atypical patients. Their first signs of trouble are usually vision loss, speech loss and difficulties making decisions or plans.
The Takeaway
Differences aside, the bottom line is that dementia is an ever-growing concern for both young and old.
"Barring the development of medical breakthroughs to prevent, slow or stop Alzheimer's, the number of Americans with the disease will triple by mid-century," Edelmayer says. And that, she adds, means that "there is an urgent need for better treatments and effective prevention strategies for people living with Alzheimer's—especially for this early onset population."