Poor smell linked to dementia risk

Drew Patchell

7 years ago

A new study has found a direct link between a poor sense of smell and a greater chance of developing Alzheimer’s and other forms of dementia.

Our ability to recognise specific smells could provide a way of spotting early damage to the brain caused by neurodegenerative disease, according to the research.

The long-term study of almost 3000 adults aged 57 to 85 involved waving sniffing sticks with various smells in front of participant’s noses to determine if they could identify the odour.

The majority of those tested, which was 78 per cent, had a normal sense of smell and could accurately identify at least four out of five common odours. The remaining 14 per cent were able to recognise three; five per cent could only identify two; two per cent could only recognise one; and one per cent couldn’t identify a single smell.

The research found that 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 failed to name a single smell had been diagnosed with dementia, while 80 per cent of those who failed to name more than one or two correct answers had developed the condition.

As reported The Australian, the study’s lead scientist Professor Jayant Pinto from the University of Chicago believes the results show that our sense of smell is 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,” she said.

“Loss of the sense of smell is a strong signal that something has gone wrong and significant damage has been done. This simple smell test could provide a quick and inexpensive way to identify those who are already at high risk.”

The five odours, in order of increasing difficulty, were peppermint, fish, orange, rose and leather.

Find out more at Journal of the American Geriatrics Society