Advanced imaging technologies have enabled scientists to higher understand the pathophysiology and outcomes of varied disease conditions more accurately by tracing the sequence of events in goal organs.
A brand new paper in Alzheimer’s & Dementia utilizes imaging findings to elucidate how a standard condition like Alzheimer’s dementia (AD) can present considerable variations depending on the sex of the person.
Study: Sex differences in risk aspects, burden, and outcomes of cerebrovascular disease in Alzheimer’s disease populations. Image Credit: Inside Creative House / Shutterstock.com
Introduction
The presence of white matter hyperintensities (WMH) is a marker of cognitive decline, which results in mild cognitive impairment (MCI) and, in a proportion of affected individuals, dementia. These pathologies could be visualized on magnetic resonance imaging (MRI) and arise because of cerebral small vessel disease (CSVD).
VMH could also be present without cognitive impairment. Nonetheless, its presence increases the danger of decreased cognition and MCI in older people without other health issues.
The small vessels of the brain undergo damage in various disease states starting from hypertension and diabetes to obesity, smoking, or drinking. Nonetheless, these aspects operate in a different way depending on the sex of the person, such that heavier females with hypertension usually tend to have a stroke than males.
This will likely be attributed to older females often being more hypertensive than males but less more likely to have well-controlled blood pressure. Menopause may trigger potentially detrimental changes in risk in females, reminiscent of a sudden rise in blood pressure that is still above desirable levels more often than males of the identical age. A history of pre-eclampsia or diabetes in pregnancy could further enhance the danger.
Earlier research has failed to offer conclusive evidence of a difference in WMH burden between the sexes. Nevertheless, some researchers imagine that these risk aspects don’t affect each sexes equally.
The present study reports sex-based differences in observed WMH progression and the differential impact of varied risk aspects on this progression, in addition to how these relate to the cognitive final result.
What did the study show?
A vascular composite rating was developed, which included the presence of self-reported diabetes, alcoholism, smoking, hypertension, and obese or obesity, in a binary format. The Hachinski rating, which is a tool employed to find out the presence of vascular disease and vascular dementia, was also assessed.
The participants were also evaluated by cognitive testing. These test results were correlated with WMH burden on the newest MRI throughout the last six months.
The mean age of males within the study was 74, whereas the common age of females was about 72. More males than females were hypertensive at 10% and 5%, respectively. Over 50% of males were hypertensive as in comparison with about 45% of females. Likewise, a greater proportion of males were smokers than women at 40% and lower than 30%, respectively, whereas 6% and a couple of% abused alcohol, respectively.
About 40% of males and 30% of females had a diagnosis of MCI. Furthermore, about 55% of females and 40% of males were considered cognitively normal.
WMH burden
The MRI findings showed age-dependent increases in WMH progression in just about all regions of the brain amongst women. Notable exceptions were observed within the temporal and parietal regions, through which each sexes exhibited equal rates of progression.
The occipital region in males exhibited more WMH. The best differences were seen within the deep brain and the occipital region.
In each sexes, WMH progression in all regions except the deep brain was related to MCI and AD. In women, the occipital region was not affected by WMH.
Men with apolipoprotein E (APOE) risk alleles exhibited greater WMH burden within the occipital and parietal regions. Comparatively, women with this genetic risk factor only exhibited greater WMH burden within the occipital region.
A better vascular composite rating was related to a greater higher total WMH burden, in addition to increased WMH in several regions for men but in all regions for ladies. Hypertension was related to more frontal WMH in males than females.
Systolic hypertension was related to greater occipital WMH in males and deeper WMH in females. Importantly, frontal WMH has been higher correlated with vascular disease as in comparison with parietal WMH with AD.
Amongst males, crucial risk factor for WMH occurrence and progression was hypertension. Amongst females, no single vascular risk factor may very well be identified; nevertheless, the vascular composite rating correlated with WMH burden.
Overall, nevertheless, there are few significant differences within the contribution of the varied risk aspects examined on this study to the WMH differences between the sexes.”
Cognitive decline
Each sexes were affected to the identical extent by WMH. As in comparison with males, females exhibited a disproportionate loss of world cognition for the WMH level. Females also experienced a greater impact on memory and functional status with the identical WMH burden.
This corroborates earlier studies reporting that AD manifests in females at lower levels of brain pathology and deteriorates faster with greater brain atrophy than males. Thus, the feminine brain could also be less resilient when affected by WMH, thereby making it more vulnerable to any future strokes or vascular pathology. This increased vulnerability may very well be the results of decreased estrogen levels that protect cognitive function.
What are the implications?
The study findings indicate that multiple cardiovascular risk aspects that would potentially be avoided or mitigated are essential in modifying the danger of further cognitive decline and WMH progression. Nonetheless, the differential contributions of varied aspects differed between men and women. This could result in further sex-specific research on cognitive decline.
Future interventions should goal hypertension in males but many risk aspects in female to assist reduce cognitive decline and progression to dementia.”
Journal reference:
- Morrison, C., Dadar, M., & Collins, D. L. (2023). Sex differences in risk aspects, burden, and outcomes of cerebrovascular disease in Alzheimer’s disease populations. Alzheimer’s & Dementia. doi:10.1002/alz.13452.