Frontiers in Human Neuroscience (2024)
DOI: https://doi.org/10.3389/fnhum.2024.1509223
Summary
Allostatic Load (AL) is a way to describe the damage to your body that happens when you are constantly stressed for a long time. This study looked at how different types of stress over your life, as well as having a healthy lifestyle, can affect Allostatic Load.
The researchers studied information from 620 people who were part of the PREVENT dementia program. They found that doing sports and having a healthy diet directly helped reduce Allostatic Load. They also found that playing sports could help a person handle stress better, but sleep was really important for this to work. Both stress and how well you deal with it affected sleep, which in turn played a big role in how Allostatic Load changed. Using healthy habits, like eating well and getting good sleep, to manage stress is likely to be good for our health.
Human Brain Mapping (2024)
DOI: https://doi.org/10.1002/hbm.26798
Summary
In this study we investigated if subtle changes on MRI scans were associated with a risk gene for late-onset Alzheimer’s disease. The Apolipoprotein e4 (APOE4) gene, can be detected by analysing the texture of brain images. One of the most well established changes in people in the early stages of dementia is that they have lower brain volumes in some brain areas such as the hippocampus. This is typically detected using structural MRI scans. However, changes on the MRI scan might be very subtle in early stages of the disease and the analysis of brain volumes might not capture them.
Therefore this study analysed the texture of structural MRI scans in both the PREVENT and the ALFA studies. Data from 1585 participants from these studies was analysed (mean age of 56 years). There were no textural or volumetric differences found in this middle-aged cohort between carriers and non-carriers of the APOE4 gene. These results suggest that structural changes in people at higher risk of dementia based on the APOE4 gene cannot be detected at this stage with simple volume analysis or even with more advanced computational methods.
Brain Communications (2024)
DOI: https://doi.org/10.1093/braincomms/fcae392
Summary
‘This study looked at “Brain Age Gap” (BAG) in middle-aged people. BAG is the difference between a person’s actual age and the age their brain appears to be based on MRI scans. A bigger gap means the brain appears older than it is.
We found that in middle-aged people, a larger BAG was linked to high blood pressure and drinking alcohol, but not to APOE4 genotype, amyloid plaques (a hallmark of Alzheimer’s disease), or how well people did on cognitive tests.
This means that some things that make your brain look older on scans are related to lifestyle factors that we can change. The study is important because it helps us understand how brain aging works in middle age, which could be the best time to start treatments to prevent dementia.
Qi Q, Deng F, Sammon R, Ritchie K, Muniz-Terrera G, Koychev I, Hutchinson S, Robinson D, Malhotra P. O’Brien J, Ritchie CW, Lawlor B, Naci, L.
Alzheimer’s Research & Therapy (2024)
DOI: https://doi.org/10.1186/s13195-024-01610-9
Summary
Building cognitive reserve through stimulating activities and occupational attainment represents a crucial yet under-explored approach to dementia prevention in mid-life. However, it remains unclear whether modifiable lifestyle factors can protect against Alzheimer’s disease (AD) processes from mid-life, differentially for females and males who carry inherited risk for late-life dementia.
This study found that engagement in stimulating activities was positively associated with episodic and relational memory, regardless of sex and APOE4 genetic status. Notably, among APOE4 carriers, this study found significant sex differences in the association between occupational attainment and episodic and relational memory: APOE4 carrier females with higher occupational attainment showed better cognition, whereas APOE4 carrier males showed the opposite effect.
These findings indicate that occupational attainment in mid-life may enhance cognitive reserve against inherited dementia risk in females but not in males. They underscore the necessity for high-precision approaches that account for biological sex and APOE4 carrier status to better inform AD prevention strategies and clinical trials.
Feng Deng, Karen Ritchie, Graciela Muniz-Terrera, Suzanne Hutchinson, Paresh Malhotra, Craig W Ritchie, Brian Lawlor, Lorina Naci.
Neurobiology of Ageing (2024)
DOI: https://doi.org/10.1016/j.neurobiolaging.2024.09.00610.1016/j.neurobiolaging.2024.09.006
Summary
This study examined whether Alzheimer’s Disease (AD) risk factors were associated with cognition and functional connectivity (FC) between two key brain structures involved with the development of AD, the Locus Coeruleus (LC) and the hippocampus.
The study found evidence that in midlife, the role of functional connectivity between the LC and the hippocampus in supporting cognition is disrupted, in individuals with a high dementia risk score. When genetic risk (APOE ε4) or family history were considered on their own, no alterations of brain–behaviour relationships were found. It was only when a risk score (CAIDE) incorporating genetic risk in combination with lifestyle factors, sex and age was considered, that such alterations were unraveled.
These results provide evidence that brain–behaviour changes in individuals with higher dementia risk scores may be driven by lifestyle factors included in the CAIDE score (i.e., blood pressure, cholesterol, physical activity, body mass index, years of education). These findings highlight the importance of modifying cardiovascular factors for the early prevention of dementia.
