According to a recent study, individuals with the gene variant associated with the highest risk of Alzheimer’s disease may experience a loss of their sense of smell earlier than those without the gene. This olfactory impairment could potentially serve as an early indicator of future memory and cognitive issues.
The study, which was published in the online edition of Neurology, focused on the gene variant known as APOE e4, which is linked to an increased risk of Alzheimer’s.
Matthew S. GoodSmith from the University of Chicago, one of the researchers involved, emphasized that assessing a person’s ability to detect odours could be a valuable method for predicting future cognitive problems. He also noted that further research is needed to confirm the findings and determine the extent of smell loss that might indicate future risk. Nevertheless, these findings hold promise, especially in the context of identifying individuals at risk for dementia in its early stages.
The research involved an at-home survey in which the sense of smell of over 865 participants was tested. This testing included both the ability to detect an odour and the ability to identify what the odour was. Participants underwent tests at five-year intervals, and their thinking and memory skills were evaluated twice, five years apart.
By analyzing DNA samples, researchers could identify individuals carrying the gene variant associated with a higher Alzheimer’s risk. Results showed that people with this gene variant were 37% less likely to have good odour detection compared to those without the gene, beginning at the ages of 65 to 69.
The gene carriers did not exhibit differences in their ability to identify odours until they reached ages 75 to 79. Once this ability started declining, it happened at a faster rate among gene carriers than in those without the gene.
At the start of the study, thinking and memory skills were similar between the two groups. However, as anticipated, those carrying the gene variant experienced more rapid declines in their cognitive abilities over time compared to those without the gene.
GoodSmith stated that understanding the mechanisms behind these relationships could provide valuable insights into the role of smell in neurodegeneration.
It’s important to note that the study’s limitation lies in the exclusion of individuals with severe dementia from the research. Further investigations are necessary to build upon these findings and gain a comprehensive understanding of the relationship between olfactory impairment and Alzheimer’s risk.