Study shows smell checks reveal dementia risk in older people

Older people with a poor sense of smell have a greater chance of developing Alzheimer’s and other forms of dementia, research has shown.

The discovery raises the prospect of using “sniffing sticks” to flag up individuals needing closer monitoring in the next five years.

The brain’s ability to sort and recognise smells may provide a way of spotting early damage caused by neurodegenerative disease, the research suggests.

But experts warned that impaired smell detection was not always a symptom of early dementia.

Almost 3,000 adults aged 5785 took part in the US study.

Those with a “normal” sense of smell could identify at least four out of five common odours.

Compared with this group, people who failed the test were more than twice as likely to develop dementia five years later.

Five years after the initial test, almost every participant who was unable to name any of the smells had been diagnosed with dementia.

Nearly 80% of those who provided only one or two correct answers had developed the condition.

There was a dose-dependent effect, the study found, with dementia rates rising in step with increasingly poor smell sense.

Lead scientist Professor Jayant Pinto, from the University of Chicago, said: “These results show that the sense of smell is closely connected with brain function and health.

“We think smell ability specifically, but also sensory function more broadly, may be an important early sign, marking people at greater risk for dementia.”

The findings are reported in the Journal of the American Geriatrics Society.