A group of researchers at Mayo Clinic found that declining sense of smell may be tied to higher dementia risk. Seniors who reported a fading sense of smell were at a moderately high risk of memory decline in the next three and a half years.
Plus, those that had the worst sense of smell, according to laboratory tests, were at the highest risk of Alzheimer’s disease. If the findings are confirmed, a simple sniff test may be enough to assess one patient’s risk of developing dementia or Alzheimer’s later on.
Mayo researchers based their findings on tests that involved 1,430 seniors with the average age of 79. Study participants were asked to take part in the same smell test, which provided them with a dozen different scents – half of the scents were food-related, while the other half were non-food-related such as gasoline, soap, and flowers.
All participants displayed no signs of dementia or Alzheimer’s disease when the study began. After the tests, they were followed for three and a half years. About 250 participants of 1,430 developed slight signs of cognitive impairment, which usually signals dementia onset.
About 64 people from the latter group eventually were diagnosed with dementia; of them, 54 were diagnosed with Alzheimer’s.
Researchers published their study in the journal JAMA Neurology.
In their paper, they wrote that participants who had a declining sense of smell were more likely to develop memory loss in the coming years, while seniors with the worst sense of smell were very likely candidates for Alzheimer’s disease
Still, the research team didn’t performed brain scans to back their hypothesis, so their link is only preliminary and needs to be confirmed. Yet, they do have a theory why loss of sense of smell and cognitive impairment may be linked.
Scientists believe that the two parts of the brain that are responsible for smell and memory coincide. So when one part is affected by aging-related degeneration, so is the other part.
On the other hand, study authors caution that a fading sense of smell does not mean that you will certainly get Alzheimer’s. There are other causes for it. Plus, most seniors face sensory loss as they age, so not all of them should worry about high risk of cognitive decline.
But sniff tests hold great potential to detect dementia and Alzheimer’s before their onset, especially if they are combined with other tests and scans. This could help doctors learn that some of their patients are at high risk of dementia years before symptoms emerge.
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