Significant variations in survival times of early onset dementia by clinical subtype

The survival rates of people with early onset dementia—diagnosed before the age of 65—vary considerably by clinical type, with sex, age, family history and co-existing conditions contributory, but not specific, factors, finds research published online in the Journal of Neurology Neurosurgery & Psychiatry. The study was carried out by researchers from the University of Eastern Finland and the University of Oulu.

Although the survival of those afflicted by dementia in older age is shorter, the overall impact on the risk of death from any cause is even greater in those with early onset disease than it is in the general public of comparable age, say the researchers.

Around 5% of dementia cases globally are categorised as early onset. But while dementia is widely recognised as a life-limiting condition among elderly people, few studies have assessed survival times and the factors associated with prognosis specifically in those with early onset disease, explain the researchers.

To explore this further and help inform the treatment and care provision of those diagnosed with early onset dementia, the researchers reviewed and reassessed all 12,490 visits made to dementia outpatient clinics in two university hospital districts in Finland between 2010 and 2021.

Some 794 confirmed cases of early onset dementia were identified, to include Alzheimer’s disease, frontotemporal dementia, alpha-synucleinopathies (especially dementia with Lewy bodies), and other early onset dementia which included vascular and mixed dementia.

Each of these cases was compared with 10 people without neurodegenerative disease, matched for age, and sex, and geographical region, from general population data registers (7930 people in total) to compare survival times.

During the study period, 215 people with early onset dementia died. Their median survival time was 8.7 years, but varied according to clinical subtype of disease.

The shortest survival of 6.9 years was seen among those with frontotemporal dementia or dementia with Lewy bodies (7 years), although those with both frontotemporal dementia and amyotrophic lateral sclerosis (ALS) lived for just over 2 years (median). Those with Alzheimer’s disease had longer survival (9.9 years, median), and the survival of those with vascular cognitive impairment was longest being over 10 years (median).

Compared with those without neurodegenerative disease the death rate from any cause among those with early onset dementia was more than 6.5 times as high. And when categorised by disease subtype, it was nearly 14 times as high in those with frontotemporal dementia, while being more than 4 times as high among those with vascular dementia, for example.

While male sex, older age, several co-existing conditions, and lower educational attainment were all associated with an increased risk of death in the whole study population, including controls, these weren’t specific to early onset dementia. The early onset dementia diagnosis itself had independently the strongest effect on survival, say the researchers.

Only diabetes, which is a known risk factor for dementia, was associated with shorter survival among those with early onset dementia.

“Overall, although the survival time in years appears shorter in older patients, the impact of dementia diagnosis on all-cause mortality is more significant in the early onset dementia age group than in the late onset patients when compared with the general population,” comment the researchers.

This is an observational study, and no definitive conclusions can be drawn about cause and effect. The researchers also acknowledge various limitations to their findings, including that most of the study participants had no genetic or neuropathological confirmation of their dementia. The numbers in each clinical subgroup were also small.

“Our study provides up-to-date early onset dementia survival rates in a validated population-based early onset dementia cohort, and highlights the substantial effect caused by its diagnosis on patients’ mortality,” conclude the researchers.

“Accurate up-to-date data on the survival and mortality rates of early onset dementia are crucial in designing healthcare structures, comprehensive patient care, and clinical trials,” they add.

The research was funded by Jane and Aatos Erkko Foundation, Wihuri Research Institute, Uulo Arhio Memorial Foundation, Päivikki and Sakari Sohlberg Foundation, the Research Council of Finland, Roche, Sigrid Jusélius Foundation, the Finnish Brain Foundation, the Finnish Cultural Foundation, the Finnish Medical Foundation, and the Finnish Parkinson Foundation.

Press release: Journal of Neurology Neurosurgery & Psychiatry

Research article:

Katisko K, Aaltonen M, Aho K, et al. Survival and mortality rates in early onset dementia. Journal of Neurology, Neurosurgery & Psychiatry Published Online First: 04 November 2025.