This Is An Early Indicator Of Dementia & It Shows Up Years Before A Diagnosis

A missed name. A forgotten appointment. Getting lost on a route regularly taken. When these become common occurrences or get in the way of daily life, it almost always warrants further investigation. In some cases, it underlying cause may be early onset dementia.

And while these are more obvious signs, a new study suggests the story starts much earlier than that. Researchers found that people with early-onset dementia (diagnosed before age 65) showed measurable declines in income and work productivity up to 15 years before anyone received a diagnosis.

The place it showed up first wasn't a doctor's office. It was a paycheck.

About the study

Early-onset dementia strikes during peak working years, often leading to reduced work capacity, earlier workforce exit, and lost household income.

What researchers wanted to understand was how far back those effects actually reach and whether the pattern differed depending on the type of dementia involved.

The study followed 793 people diagnosed with early-onset dementia at two Finnish hospitals over 12 years.

For each person, researchers matched 10 people without dementia by age and sex, building a comparison group of nearly 8,000 individuals. They then used national tax records to track earnings over time and measure the growing gap between the two groups.

Income losses began years, sometimes decades, before diagnosis

The income gap between people with early-onset dementia and their peers didn't appear overnight. It widened steadily over time, stretching back 15 years before anyone received a diagnosis.

By the time of diagnosis, the average annual gap had grown to around €12,021 per person. Even 15 years out, a difference was already measurable, at about €2,774 per year.

How early those losses started depended on the type of dementia:

One caveat worth keeping in mind: because the study looked back at existing records rather than following people in real time, the findings describe a pattern, not a direct cause-and-effect relationship.

Why work performance may be an early signal

The biology behind Alzheimer's and related conditions can start changing in the brain 20 or more years before anyone gets a diagnosis. That's a long runway.

And during that time, there may be small shifts in focus, processing speed, and the ability to plan or problem-solve. When those capacities start to dip, even a little, it can show up in output and earning potential well before it would ever register in a clinical setting.

Someone might take longer to finish tasks, make more mistakes, or find it harder to manage projects they used to handle without thinking. The easy explanation is stress, burnout, or just getting older, which is exactly why these shifts go unnoticed for so long.

What this means for earlier recognition

Most people with early-onset dementia wait years for a diagnosis. Recognizing that shifts in work performance or financial management can be early signals, rather than unrelated life stressors, could help people seek evaluation sooner.

While there's currently no cure for most forms of dementia, catching it earlier gives people more time to make informed decisions about their care and future. If you've noticed a meaningful, unexplained shift in work performance or financial management (especially in someone under 65), it may be worth bringing up with a doctor.

How to protect your brain during your working years

The research on brain health is consistent. The habits you build now have a real impact on how your brain ages. A few evidence-backed strategies, practiced consistently over time, can make a meaningful difference.

The takeaway

The gap between when early-onset dementia begins and when it's diagnosed is wider than most people realize, and the financial record may be one of the first places it shows up.

Knowing what to watch for, and building protective habits early, gives you a real advantage. Earlier awareness means more time to act.