New study says loss of smell in 60+ may be linked to risk of Alzheimer's

New Delhi: A study conducted by the University of Chicago Medicine said found that some people who carry a gene variant - APOE e4 - are at the highest risk of Alzheimer’s disease, according to the study. People who carry this gene may lose the ability to smell or detect odour earlier than those without the gene variant.

The findings showed that people who had this particular gene variant were 37 per cent less likely to detect odour than people who didn't have the gene. The gene carriers began experiencing loss of smell between the ages of 65 and 69. Moreover, people with the gene couldn't identify what odour they were smelling until they reached age 75 to 79, as per the study.

Matthew S GoodSmith from the University of Chicago said that these findings can help predict dementia risk early in the disease. "Testing a person’s ability to detect odours may be a useful way to predict future problems with cognition. While more research is needed to confirm these findings and determine what level of smell loss would predict future risk, these results could be promising, especially in studies aiming to identify people at risk for dementia early in the disease. Identifying the mechanisms underlying these relationships will help us understand the role of smell in neurodegeneration," he said.

The researchers conducted at-home surveys to study the sense of smell of more than 865 people. The test included people's ability to detect an odour and identify what they were smelling.

Tests were given at five-year intervals. People’s thinking and memory skills were also tested twice, five years apart. DNA samples helped researchers identify who carried the gene and were at an increased risk of Alzheimer’s.

The study determined that after the ability to identify odours declined, the people with APOE e4 gene experienced a rapid decline in their overall thinking skills compared to those without the gene.

Published in Neurology journal, the new findings may serve as an early indicator of memory decline and cognitive abilities. However, people with severe dementia were not included in the study.