What Age Can Dementia Start?
Kim Trevey on 
What Age Can Dementia Start?
In February this year, the Journal of Alzheimer’s Disease released information about the youngest case of diagnosed Alzheimer’s on record. The patient is only 19 years old.
The young man lives in China and has been experiencing issues with memory loss since he was 17. His memory loss grew so severe, he had to drop out of high school. After brain imaging scans revealed damage to his hippocampus, a part of the brain responsible for memory, doctors determined he likely has Alzheimer’s disease. He has no history of head trauma, stroke or genetics that could be causing such an early-onset case.
While this young man’s case is incredibly rare, early-onset dementia and Alzheimer’s disease is on the rise in younger Americans (which we’ll talk more about below). Because of this, understanding what early-onset Alzheimer’s is and the warning signs is crucial.
What is early-onset Alzheimer’s disease?
Most cases of dementia are found in older adults, age 65 and up. This is because age is largely associated with symptoms of dementia. However, people can develop symptoms of dementia as early as their twenties, thirties, forties and fifties. Any case diagnosed before age 65 is considered early-onset dementia or Alzheimer’s disease.
Most cases of early dementia involve rare types of Alzheimer’s disease such as:
1. Posterior cortical atrophy Alzheimer’s
Early signs of this type of Alzheimer’s disease include difficulty with visual information like judging distances.
2. Logopenic aphasia Alzheimer’s
Difficulty with language, such as finding certain words, is typically an early sign of this type of rare Alzheimer’s.
3. Behavioral/dysexecutive Alzheimer’s
Early symptoms for this type of Alzheimer’s disease include difficulty with decision-making and inappropriate social behavior.
Alzheimer’s can also be a genetic disease, though this is rare. Certain genetic mutations can cause Alzheimer’s or increase someone’s risk of developing Alzheimer’s disease. This genetic form of Alzheimer’s more commonly appears earlier in life, before the age of 65 and has a 50% chance of being passed to a child.
Genetic testing can determine if you carry a gene mutation that increases your risk for Alzheimer’s disease.
Why is early-onset Alzheimer’s on the rise?
According to a Blue Cross Blue Shield (BCBS) study, early-onset dementia and Alzheimer’s disease increased three-fold from 2013 to 2017, rising to about 131,000 reported cases in commercially insured adults. The average age of those diagnosed was 49, and a larger percentage were women.
The rise in cases seems to be more prevalent in the younger age group, age 30-44, which saw a 373% increase. Diagnoses in those age 45-54 saw a 311% increase. And for those age 55-64, cases rose by 143%.
Why is this happening?
There are a few possible reasons.
The BCBS report noted 57% of those who had early-onset dementia or Alzheimer’s had also filled a prescription for depression medication in the year prior to their diagnosis. The Alzheimer’s Organization points out that this link does not mean depression causes Alzheimer’s. It could, however, mean that there’s an unknown, underlying condition that causes depression and Alzheimer’s disease.
The Alzheimer’s Organization also notes that the rise in cases could be due to the rise in doctors’ knowledge and awareness of dementia and Alzheimer’s. As doctors become more aware of the signs and symptoms, it’s possible that they are conducting more screenings and, therefore, able to diagnose people at a younger age.
The majority of the 6.5 million people who are living with Alzheimer’s in America today are older adults, with 70% of cases in those who are 75 and older. Still, you can get an early dementia or Alzheimer’s diagnosis. These are typically associated with rare forms of Alzheimer’s or a genetic mutation.
With early-onset cases on the rise, it’s important that early-onset Alzheimer’s is understood in the broader Alzheimer’s community. It’s not as rare as we tend to think, and the earlier doctors can detect it, the earlier they can intervene with medications, treatments and therapies, giving people the best quality of life possible as they live with the disease.
