Alzheimer's Symptoms Can Appear Decades Earlier Than Thought, New Study Finds. Here's What To Know

Yahoo

15-05-2025

Alzheimer's symptoms and changes in cognitive function typically start to appear after age 65.
A new study published in Lancet Regional Health-Americas finds that Alzheimer's symptoms can present much earlier than thought, as early as the mid-20s.
Experts say that in addition to staying active, eating healthy, avoiding tobacco, and limiting alcohol, it's a good idea to try to use your brain "vigorously" to stay sharp.
When you close your eyes and think about Alzheimer's disease, you're probably conjuring up an image of an older person. That makes sense, because the symptoms usually start to rear their ugly heads after age 65. But new research suggests that the devastating disease may actually influence a person's cognitive function decades before they're actually diagnosed.
The groundbreaking study, which was published in the journal Lancet Regional Health – Americas, is raising a lot of questions about early biomarkers for Alzheimer's disease—and how to keep your brain healthy, starting from a younger age.
Here's what the study found, plus what neurologists want you to keep in mind when digesting the information.
Meet the experts: Clifford Segil, DO, is a neurologist at Providence Saint John's Health Center in Santa Monica, CA; Amit Sachdev, MD, MS, is the medical director in the Department of Neurology at Michigan State University.
For the study, researchers analyzed data from Waves IV and V of the National Longitudinal Study of Adolescent to Adult Health, which is a long-term health study that has tracked teens since the mid-90s.
The researchers did a slew of in-home interviews, cognitive tests, and physical exams, and collected blood samples from thousands of participants in their 20s and 30s. Ultimately, 1,112 study participants who did in-home interviews were given cognitive tasks like immediate word recall, delayed word recall, and backward digit span. They also provided a sample for genetic testing. The researchers then tied those scores to Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) scores in 529 people.
The researchers discovered that certain risk factors and biomarkers linked to Alzheimer's disease may influence a person's cognitive function starting in their mid-20s and continuing onwards. 'Key risk factors for Alzheimer's disease are linked to cognitive function as early as ages 24–44, highlighting the need for early prevention in the US,' the researchers wrote in the conclusion.
The study focused on a few different factors, including the CAIDE score. The list included things like a person's age, education, sex, systolic blood pressure (the top number in a blood pressure reading), body mass index, cholesterol, physical activity, and the gene variant apolipoprotein E ε4 allele (APOE ε4), a genetic risk factor for Alzheimer's disease.
The researchers also discovered that ATN (amyloid, tau, neurodegeneration), and immune biomarkers linked to Alzheimer's disease may be present and related to cognition in people in their 40s and younger.
Sort of. 'When I see younger patients concerned with getting dementia when they are elderly, I 'risk stratify' and do the same tests I would do in an octogenerian concerned they have dementia,' says Clifford Segil, DO, a neurologist at Providence Saint John's Health Center in Santa Monica, CA.
That means doing blood tests to look for reversible causes of memory loss—including thyroid tests and checking vitamin levels like B12. 'I would also obtain a structural picture of their brain to see if they have had silent strokes or atrophy,' Dr. Segil says.
The only actual available "test" for Alzheimer's disease in younger people would be to check someone's APOE 4 levels, which is considered the strongest genetic risk factor for Alzheimer's disease, Dr. Segil says. 'But this [test] being positive in a young patient would be challenging to say has any clinical significance,' he adds.
There are a few things you can do right now to make sure you have the healthiest brain as you get holder. Aside from eating a healthy diet, staying active, avoiding tobacco, and limiting your alcohol consumption, it's a good idea to 'vigorously' use your brain, says Amit Sachdev, MD, MS, medical director in the Department of Neurology at Michigan State University.
'This is best achieved through self-investment in education but also through socialization and human interaction,' he says. 'Working on finding and cultivating new friends and interests in youth helps to develop those old friendships that are so important later in life.'
Dr. Segil also recommends keeping your body and mind busy to maintain your brain health.
Ultimately, if you're concerned about your dementia risk or if you have a family history of the disease, check in with your primary care physician, who should be able to offer some personalized guidance.
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