A failing nose: the unexpected predictor of dementia and Alzheimer’s

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The human sense of smell provides more than just alerts to potential dangers like fire or culinary delights.

Researchers at the University of Chicago Medicine have found that a decline in one’s sense of smell over time could predict cognitive decline and structural brain changes linked to Alzheimer’s disease and dementia.

The Study and its Significance

The team’s study, published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, suggests that smell tests could help identify cognitive impairment earlier in patients.

Over 6 million Americans suffer from Alzheimer’s, a disease characterized by memory loss and other symptoms such as mood changes and difficulty with everyday tasks.

Early detection could be crucial in managing the disease more effectively.

The Findings

The researchers utilized anonymized patient data from the Memory and Aging Project (MAP), a long-term study focused on chronic conditions and neurodegenerative diseases.

The participants were tested annually for their ability to identify certain smells, cognitive function, and signs of dementia.

The study discovered that a rapid decline in a person’s sense of smell during a period of normal cognition could predict several features of Alzheimer’s disease, including smaller gray matter volume in areas of the brain associated with smell and memory, worse cognition, and a higher risk of dementia.

The risk associated with smell loss was found to be similar to carrying the APOE-e4 gene, a known genetic risk factor for developing Alzheimer’s.

Looking Ahead

The researchers aim to validate their findings by examining brain tissue for markers of Alzheimer’s and assessing the effectiveness of smell tests as a method of early dementia detection.

Future research would also need to include a more diverse population to determine if underrepresented groups are affected in the same way.

The importance of the sense of smell to brain health and aging has been a key area of research for the team.

Earlier work had revealed that older adults with no sense of smell were three times more likely to die within five years—a stronger predictor of death than lung disease, heart failure, or cancer.

If you care about brain health, please read studies about how the Mediterranean diet could protect your brain health, and blueberry supplements may prevent cognitive decline.

If you care about Alzheimer’s, please read studies about vitamin D deficiency linked to Alzheimer’s and vascular dementia, and blood pressure problem at night may increase Alzheimer’s risk.

The study was published in Alzheimer s & Dementia.

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