Scientists discover one dementia clue up to 15 years before diagnosis

People diagnosed with early-onset dementia were found to have shown measurably lower work productivity as much as 15 years before their diagnosis was given, according to a new study of nearly 800 patients in Finland.

The research, published July 8, 2026, in Neurology, the medical journal of the American Academy of Neurology, found that income losses tied to the condition grew steadily in the years leading up to diagnosis, adding up to an average of €74,577—about $86,000—per person over the course of the study.

Early-onset dementia generally refers to any type of dementia diagnosed in someone under the age of 65, and that is the definition the researchers went with while pursuing their study.

“This study is significant as it supports what many dementia experts have observed in clinical practice,” Dr. Edmundo Rodriguez-Frias, the medical contributor of Full of Life, a recovery center in New Jersey, told Newsweek.

“Cognitive decline likely occurs for several years prior to receiving the official diagnosis of a cognitive disorder. The first sign of such cognitive decline could potentially be a noticeable decline in job performance, especially for those diagnosed with early-onset dementia who are still working.

“This research shows the value of recognizing early signs of potential problems. If a previously high-functioning individual develops persistent difficulty with planning, task management, making decisions, language use, or adapting to new tasks, especially if others also notice these changes, it may be worth talking to your doctor instead of dismissing the problem as normal aging or work-related stress.”

Newsweek reached out to the study’s authors for additional comment via email.

How the Study Was Conducted

Researchers tracked 793 people diagnosed with early-onset dementia at two hospitals in Finland over a 12-year period. Each patient was matched by age and sex to 10 people without dementia, for a comparison group of 7,926 people.

Among those with dementia, 421 had Alzheimer’s disease, 179 had frontotemporal dementia, and 46 had alpha-synucleinopathies, a category that includes dementia with Lewy bodies and Parkinson’s disease dementia. The remaining 147 had other forms of dementia, including vascular cognitive disorders and mixed dementias.

Using national tax records, researchers compared incomes between the two groups. National registries supplied data on education levels and other health conditions, which researchers factored into their analysis to isolate the effect of dementia on income.

Productivity Losses Varied by Dementia Type

The timing of income decline differed depending on the type of dementia a person later developed.

For people diagnosed with Alzheimer’s disease, productivity losses became apparent about six years before diagnosis. For those with frontotemporal dementia, the decline began 11 years earlier. Among people with alpha-synucleinopathies, losses only showed up around the time of diagnosis itself.

People with other forms of dementia, including vascular and mixed dementias, showed consistently high productivity losses throughout the years studied.

“Our study found productivity loss was strikingly large, averaging around 12,000 Euros, or approximately 13,800 U.S. dollars, per year per person, with losses beginning up to 15 years before diagnosis,” study author Eino Solje, from the University of Eastern Finland, said in a statement.

“These findings may partly be explained by delays in diagnosis, which can prolong the period of unrecognized symptoms, and they underscore the harmful, long-term socioeconomic impact of early-onset dementia.”

Limitations and What Comes Next

The study looked back at existing data rather than following patients forward in time, so it cannot establish that early-onset dementia directly causes reduced productivity—only that the two are linked. Researchers noted the findings do not prove cause and effect.

Solje said future research should incorporate neuropsychological tests to track cognitive changes over time, and that new interventions should be developed to prevent or delay productivity decline in people who go on to develop early-onset dementia.

“For clinicians practicing geriatric medicine, the importance of an earlier diagnosis lies in providing individuals and their families additional time to prepare, reverse contributing factors to the development of cognitive symptoms, optimize cardiovascular risk factor control, investigate emerging treatment options when indicated, and provide access to relevant support services,” Rodriguez-Frias said.

“Future studies that examine both workplace patterns in addition to cognitive assessments and biomarkers should attempt to define whether identifiable functional changes can assist in identifying workers who may be best served by initial evaluations and avoid inducing unnecessary anxiety or over-diagnosis.”

Reference

Solje, E., et al. (2026). Long-Term Income and Productivity Losses in Individuals With Early-Onset Dementia. Neurology. Long-Term Income and Productivity Losses in Individuals With Early-Onset Dementia.

Contact Newsweek editors on this story: Kara Dolman and James Debens