Alzheimer’s gene risks early onset smell loss, research shows

New research has found people who carry a gene associated with Alzheimer’s are at an increased risk of early onset smell loss.

Yesterday, researchers from Minneapolis announced that individuals who possess the gene variant associated with the strongest risk for Alzheimer’s disease may lose their ability to detect odours earlier than people who do not have it.

According to experts, who published their findings in the July issue of Neurology, the medical journal of the American Academy of Neurology, losing your sense of smell could be an early sign of future memory and thinking problems – symptoms associated with Alzheimer’s.

‘Testing a person’s ability to detect odours may be a useful way to predict future problems with cognition,’ Matthew S. GoodSmith, author of the study, said. ‘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.’

To gather their research, which was supported by the National Institutes of Health, National Institute on Aging and National Institute of Diabetes and Digestive and Kidney Diseases, experts conducted at-home surveys that included testing the sense of smell of over 865 people – both their ability to detect a smell at all and their ability to identify what odour they were experiencing. Tests were given at five-year intervals.

In addition, people’s thinking, and memory skills were also examined twice, five years apart. DNA samples gave researchers information about who carried the gene associated with an increased risk of Alzheimer’s.

For the test to see if people could detect smells, individuals were scored between zero and six based on how many of the different odours they could identify. 

Results from the experiments displayed people who carried the gene variant were 37% less likely to have good odour detection than people without it. Researchers accounted for other factors that could affect the results, such as age, sex, and educational level. The gene carriers started experiencing reduced smell detection at age 65 to 69.

Following this, the tests displayed the people carrying the gene variant did not show a difference in their ability to identify what odour they were smelling until they reached the age of 75 to 79.

However, once they began to lose the ability to detect smells, the gene variant experienced rapid declines in their thinking skills over time than those without the gene.

Commenting on these findings, Mr GoodSmith said: ‘Identifying the mechanisms underlying these relationships will help us understand the role of smell in neurodegeneration.’

News of these experts findings has been published amidst other groundbreaking research that has been taking place for Alzheimer’s. At the end of last year, the first-ever drug was found to help treat the disease. 

Image: Ruslan Zh