Pre-Menopausal Ovary Removal Linked to Decreased Brain White Matter: Study

According to a study published in the Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, women who have their ovaries removed before menopause, particularly before the age of 40, have reduced white matter integrity in multiple regions of the brain later in life.

Premenopausal bilateral oophorectomy (PBO) causes abrupt endocrine dysfunction (e.g., loss of estrogen, progesterone, testosterone, and an increase in gonadotropins). Studies suggest that females with PBO are at an increased risk of cognitive impairment and dementia.

Long-term ovarian hormone deprivation in rats is associated with reduced white matter integrity. Among humans, females have lower white matter fractional anisotropy compared to males across multiple brain regions, potentially reflecting differences in sex hormone exposure.

For the study, the research team examined data from the Mayo Clinic Study of Aging to identify women over the age of 50 with available diffusion tensor imaging, a magnetic resonance imaging (MRI) technique that measures white matter in the brain. The cohort was comprised of:

1.22 participants who had premenopausal bilateral oophorectomy (PBO) before age 40

2.43 participants who had PBO between the ages of 40 and 45

3.39 participants who had PBO between the ages of 46 and 49

4.907 participants who did not have PBO before the age of 50.

The results showed that females who had premenopausal bilateral oophorectomy before the age of 40 had significantly reduced white matter integrity in multiple regions of the brain. There were also trends in some brain regions such that women who had PBO between the ages of 40-44 or 45-49 years also had reduced white matter integrity.

“Having both ovaries removed results in an abrupt decrease in both estrogen and testosterone in women. Therefore, one possible explanation for our results is the loss of both estrogen and testosterone. While these findings are important for women to consider before having premenopausal bilateral oophorectomy for non-cancerous conditions, we need a larger and more diverse cohort of women to validate these results,” said Michelle Mielke, the study’s corresponding author.

Reference: Michelle M. Mielke, Ryan D. Frank, Luke R. Christenson, Robert I. Reid, Julie A. Fields, Zhenya E. Knyazhanskaya, Firat Kara, Prashanthi Vemuri, Walter A. Rocca, Kejal Kantarci; Premenopausal bilateral oophorectomy and brain white matter brain integrity in later-life; Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association; https://doi.org/10.1002/alz.13852