A recent brain imaging study showed that lower estrogen levels in postmenopausal women may be linked to brain lesions that trigger Alzheimer’s disease, commonly known as Alzheimer’s. The researchers studied many middle-aged subjects with cognitive health in detail, suggesting that this mechanism may be one reason why the proportion of female patients is higher than that of men.
Study author Lisa Mosconi of Weill Cornell Medical School said: “About two-thirds of Alzheimer’s patients are women because women generally live longer than men.”
In recent years, many researchers have begun to explore the underlying physiological causes of this phenomenon to reveal how such a clear gender difference is caused.
A study last year, for example, identified a number of gender-specific genes that may increase a woman’s risk of developing Alzheimer’s disease.
Another study showed differences in brain structure and function, or accelerated the spread of toxic proteins.
The new study builds on what researchers call the “estrogen hypothesis”, in which women appear to be more sensitive to Alzheimer’s disease.
Because postmenopausal estrogen levels drop, it may increase susceptibility to brain changes associated with neurodegenerative diseases.
Based on this new hypothesis, the study recruited 85 women and 36 male subjects between the ages of 40 and 65.
All of the subjects were selected from volunteers who had cognitive health and participated in detailed MRI and PET scans to measure the levels of four biomarkers associated with Alzheimer’s disease.
These markers include the level of amyloid protein accumulation and the incidence of glucose metabolism. The results were 30% higher than the average accumulation of amyloid protein, 22% lower glucose metabolism, and about 11% lower levels of gray matter than in the male control group.
After controlling the variables, the study found that menopausal status was the most consistent predictor of these Alzheimer’s biomarkers, adding a more reliable weight to the estrogen hypothesis.
Details of the study have been published in the recently published journal Neurology.
Originally titled “Sex-driven modifiers of Alzheimer risk, a multimodality brain imaging study.”