About 78 percent of subjects correctly named at least four out of five scents, about 14 percent could make out three out of five, five percent could recognize two scents, two percent could single out one, and one percent were not able to identify any.
After five years, they found that almost all of those who could not identify any of the items had been diagnosed with dementia, and nearly 80 percent who could only smell one or two had dementia.
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"These results show that the sense of smell is closely connected with brain function and health," lead author Jayant M. Pinto said in a statement. "We think smell ability specifically, but also sensory function more broadly, may be an important early sign, marking people at greater risk for dementia."
Despite their results, scientists say participants could have lost their sense of smell for other reasons, and the sniff test is not a telltale predictor of dementia.
However, their findings could help identify people at risk for the disease.
"Our test simply marks someone for closer attention," Pinto said. "Much more work would need to be done to make it a clinical test. But it could help find people who are at risk. Then we could enroll them in early-stage prevention trials."
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