Early-onset dementia refers to cases diagnosed before age 65. Survival varies widely by clinical type. Sex, age, family history, and other health conditions do not consistently predict risk. This finding comes from research published online in the Journal of Neurology Neurosurgery & Psychiatry.
Older adults with dementia generally have shorter survival. But for those with early-onset dementia, the risk of death from any cause is even higher than for people of the same age without dementia.
About 5% of global dementia cases are early onset. While dementia is often seen as a condition of older adults, few studies have looked at survival times and prognosis in younger patients. The researchers sought to fill this gap to improve care and treatment for those diagnosed early.
The study analyzed 12,490 visits to dementia outpatient clinics in two Finnish university hospital districts from 2010 to 2021. They identified 794 confirmed cases of early-onset dementia. Diagnoses included Alzheimer’s disease, frontotemporal dementia, alpha-synucleinopathies (especially Lewy body dementia), and “other” or “mixed” dementia, which included vascular cognitive impairment.
For comparison, the researchers matched survival times with 10 general-population peers from registers, matched for age, sex, and region (9,930 people in total).
During the study period, 215 people with early-onset dementia died. Their average survival time was about 9 years, but this varied by subtype.
Frontotemporal dementia or Lewy body dementia had the shortest average survival, near 7 years.
Those with both frontotemporal dementia and motor neuron disease (ALS) lived a little more than 2 years on average.
Alzheimer’s disease patients survived about 10 years on average.
Vascular cognitive impairment patients lived the longest, over 10 years on average.
Compared with people without neurodegenerative disease, those with early-onset dementia had a death rate more than 6.5 times higher. Subtype details showed even larger gaps: nearly 14 times higher for frontotemporal dementia and more than 4 times higher for vascular cognitive impairment.
Certain factors increased the risk of death across the board. Male sex, older age, multiple co-existing conditions, and lower education were linked to higher mortality, but these factors were not specific to early-onset dementia. The diagnosis itself was the strongest, independent predictor of survival time. Diabetes was the only comorbidity linked to shorter survival among those with early-onset dementia.
The researchers note that, while survival years may be shorter for older patients, the impact of an early-onset dementia diagnosis on all-cause mortality is larger when compared with the general population.
Limitations include the observational design and some data gaps. Most participants did not have genetic or neuropathological confirmation, and numbers in some clinical subgroups were small.
The study authors say their work provides up-to-date survival rates for early-onset dementia in a population-based cohort. They emphasize the substantial effect of an early-onset diagnosis on mortality. They also stress the need for accurate, current data to shape healthcare, patient care, and clinical trials for early-onset dementia.
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