In women with menopause, low estrogen levels decline the volumes of “gray matter,” a key brain region that is also affected in Alzheimer’s disease.
However, a new study from the researchers of Weill Cornell Medicine and the University of Arizona has suggested that greater cumulative exposure to estrogen in life may counter this brain-shrinking effect, according to Science Daily.
The study, published in the journal Neurology, looked at personal histories, MRI scans, and cognitive tests of 99 women in their late 40s to late 50s.
The researchers confirmed the link between menopause and lower gray matter volume (GMV) in brain areas vulnerable to Alzheimer’s.
They also found the link between indicators of higher overall estrogen exposure and higher GMV in some of these brain areas. The indicators of higher overall estrogen exposure include a longer span of reproductive years (menarche to menopause), more children, and the use of menopause hormone therapy or oral contraceptives.
Although the study was observational, it adds to the evidence that estrogen could have a protective effect on the female brain, reducing the risk of Alzheimer’s.
Senior author Dr. Lisa Mosconi said, “Our findings suggest that while the menopause transition may bring vulnerability for the female brain, other reproductive history events indicating greater estrogen exposure bring resilience instead.”
In the United States, experts estimate that nearly two-thirds of those living with Alzheimer’s are women. They believe that the higher prevalence of the condition in women may be due to women’s greater longevity, and one leading hypothesis is that it could be due to low estrogen.
Estrogen levels start to decline after menopause, and as the study from Dr. Mosconi has shown, women tend to experience significant GMV loss during this transition.
And this volume loss occurs in brain regions that are heavily affected in Alzheimer’s which is why the mid-life loss of estrogen in women may be responsible for increasing the risk of Alzheimer’s.
The findings support the idea that estrogen can be protective in women. The researchers suggest that further investigation could yield medical or lifestyle changes that help women reduce their risk of developing Alzheimer’s
The study’s first author Eva Schelbaum said, “We’re hoping now to get further into the details of these links between estrogen and GMV, for example by comparing the effects of surgical menopause and spontaneous menopause, and by focusing specifically on certain types of estrogen exposure, such as menopause hormone therapy.”
“The goal as always is to understand why Alzheimer’s affects more women than men, and how we can reduce that risk,” she added.
