Oestrogen may have a protective effect on the female brain
A study of menopausal women suggests that greater cumulative exposure to oestrogen in life, for example from having a longer reproductive span or from having taken hormone replacement therapy (HRT), may potentially reduce the brain-shrinking effects of Alzheimer’s disease.
“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,” said Dr. Lisa Mosconi, an associate professor of neuroscience in neurology at Weill Cornell Medicine, New York, and director of the Women’s Brain Initiative, and associate director of the Alzheimer’s Prevention Clinic at Weill Cornell Medicine and New York-Presbyterian/Weill Cornell Medical Center.
The findings come from an analysis of personal histories, MRI scans and cognitive tests on 99 women in their late 40s to late 50s and a comparison group of similarly aged men. It confirmed that the post-menopausal and peri-menopausal women (starting menopause), compared with the pre-menopausal women and the men, had significantly lower gray matter volume (GMV) – adjusted for age and head size – in areas of the brain which are heavily affected by Alzheimer’s.
Receptors for oestrogen molecules are found in cells throughout women’s brains, and the sex hormone has long been known to help steer brain development and behaviour; and has a nourishing and protecting role in the central nervous system. However, oestrogen levels decline steeply during the transition through menopause as women experience significant GMV loss. It is suspected that women’s mid-life loss of oestrogen may be a key factor behind the higher risk of Alzheimer’s.
The new study showed that having greater oestrogen exposure, in contrast, was associated with greater GMV in certain brain areas to be affected by aging and Alzheimer’s: longer reproductive span, having had more children, and having used HRTs, for example, was each significantly linked to more GMV in different parts of the brain.
The findings support the idea that oestrogen can be protective, the researchers said, and suggest that further investigation of the specific biological pathways underlying this effect could yield medical or lifestyle changes that help women reduce their risk of cognitive decline with aging and Alzheimer’s.
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