New research indicates that individuals carrying the APOE e4 gene variant, which is strongly linked to a higher risk of Alzheimer’s disease, may experience an early decline in their ability to detect odors. This finding suggests that testing a person’s odor detection capability could be a potential method to predict future cognitive problems and identify those at risk of dementia at an earlier stage.
A recent study published in Neurology, the medical journal of the American Academy of Neurology, examined over 865 people through an at-home survey to evaluate their sense of smell, both in terms of odor detection and odor identification. The participants were tested at five-year intervals, and their thinking and memory skills were also assessed twice, five years apart. DNA samples were used to determine who carried the APOE e4 gene variant associated with an increased risk of Alzheimer’s.
The study revealed that people carrying the gene variant were 37% less likely to have good odor detection compared to those without the gene, starting at around age 65 to 69. However, the ability to identify specific odors did not differ until age 75 to 79. From that point, the gene carriers’ ability to detect odors declined more rapidly than those without the gene. As expected, the carriers of the gene variant experienced more rapid declines in their thinking skills over time compared to the non-carriers.
While further research is needed to confirm these findings and determine the exact level of smell loss that could predict future cognitive risk, the results hold promise, particularly for studies aiming to identify individuals at risk of dementia early on in the disease.
It’s worth noting that the study’s limitation is that it did not include people with severe dementia. The research was supported by the National Institutes of Health, National Institute on Aging, and National Institute of Diabetes and Digestive and Kidney Diseases. Understanding the underlying mechanisms of these relationships will be crucial to comprehend the role of smell in neurodegeneration, according to study author Matthew S. GoodSmith from the University of Chicago.
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Frequently Asked Questions (FAQs) about Alzheimer’s risk
What does the research reveal about the APOE e4 gene variant and Alzheimer’s risk?
The research indicates that individuals carrying the APOE e4 gene variant, which is strongly correlated with Alzheimer’s risk, may experience an early loss of their ability to detect odors. This diminished odor detection ability could serve as an early warning sign of future cognitive and memory difficulties.
How could testing odor detection help in predicting cognitive problems?
Testing a person’s ability to detect odors may be a useful way to predict future cognitive problems. The study found that individuals with the APOE e4 gene variant, who are at a higher risk for Alzheimer’s, showed reduced smell detection at an earlier age compared to those without the gene. Monitoring odor detection could potentially identify people at risk for dementia earlier in the disease progression.
What did the study involve?
The study involved an at-home survey of over 865 participants, evaluating their sense of smell at five-year intervals. Participants were tested for their ability to detect odors and identify specific smells. Their thinking and memory skills were also assessed twice, five years apart. DNA samples were used to determine the presence of the APOE e4 gene variant associated with Alzheimer’s risk.
Were other factors considered in the study?
Yes, researchers accounted for other factors that could affect the results, such as age, sex, and educational level, to ensure the accuracy of their findings.
What limitations were identified in the study?
A limitation of the study is that people with severe dementia were not included, which may have influenced the overall findings. However, the study provides valuable insights into the relationship between odor detection, the APOE e4 gene variant, and cognitive decline.
What is the significance of these findings?
The research sheds light on the potential role of smell loss as an early indicator of Alzheimer’s risk. Identifying individuals with reduced odor detection, especially those carrying the APOE e4 gene variant, could help in developing strategies to detect and address cognitive problems at an earlier stage, potentially improving outcomes for those at risk of dementia.
Who supported the study?
The study was supported by the National Institutes of Health, specifically the National Institute on Aging and the National Institute of Diabetes and Digestive and Kidney Diseases.
More about Alzheimer’s risk
- Neurology study: Association of APOE ε4 Status With Long-term Declines in Odor Sensitivity, Odor Identification, and Cognition in Older US Adults
- University of Chicago: Matthew S. GoodSmith
- American Academy of Neurology: Neurology Journal
- National Institutes of Health: NIH
