Over 85 year olds without dementia are almost nine times more likely to go on to develop the disease
if they have had an episode of delirium, a European study finds.

At baseline 77 per cent of the patients who had already experienced delirium had dementia,
while only 33 per cent of those who had never been delirious had dementia, the population-based
cohort study of 553 Finnish people aged over 85 found.

Delirium was also associated with worsening dementia severity, the authors said.

“This means that delirium, or the acute causes of delirium, could be a newly discovered
cause of dementia,” said Dr Davis, although more data was needed to test this hypothesis.

Autopsies carried out on the brains of study participants who died during the decade of the
study showed differences between the brains of typical dementia patients and the brains of those
who had developed dementia after an episode of delirium. Several neuropathological markers known
to be connected with dementia were found in the brains of non-delirium dementia patients, but
in the 10 dementia patients who developed their disease after delirium, these markers were not found.

Although an “intriguing finding,” the study was insufficiently powered to determine whether
delirium was genuinely associated with an altered pattern of dementia pathology,” they wrote.

Up to 30% of delirium was preventable, said the authors.

REFERENCE: 2012.03.015 Brain 2012;
doi: 10.1093/brain/aws190