How having ovaries removed before menopause affects brain structure
Women who have both of their ovaries removed prior to going through menopause show reduced white matter integrity on imaging.
These changes are especially prevalent in women who undergo premenopausal bilateral oophorectomy (PBO) before the age of 40, new research suggests.
“We know that having both ovaries removed before natural menopause causes abrupt endocrine dysfunction, which increases the risk of cognitive impairment and dementia,” Michelle Mielke, PhD, professor and chair of epidemiology and prevention at Wake Forest University School of Medicine, and colleagues explain. “But few neuroimaging studies have been conducted to better understand the underlying mechanisms.”
How menopause affects the brain has been the subject of much discussion, but less is known about the influence of removing the ovaries prior to menopause and whether it has any bearing on neurological health. This latest study offers new evidence to suggest abrupt alterations in hormone production impact the brain on a structural level.
For the study, researchers identified women over the age of 50 in the Mayo Clinic Study of Aging who had undergone bilateral PBO and diffusion tensor MR imaging of the brain. The team divided the more than 1,000 participants into groups based on the age they were when they had their ovaries removed—before 40, between 40 and 45, between 46 and 49, and after 50.
The majority of participants waited until after they turned 50 to have their ovaries removed. The group that underwent PBO prior to the age of 40 showed significantly lower fractional anisotropy and higher mean diffusivity in the white matter of several areas of the brain, including the anterior corona radiata, genu of the corpus collosum, inferior fronto-occipital fasciculus, superior occipital, and superior temporal. The group who had surgery between the ages of 45 and 49 also showed changes, but those were not statistically significant.
Around 80% of the women included in the analysis had received estrogen replacement therapy, but even after adjusting for this, the results did not differ. This could be due, in part, to the decrease in another hormone triggered by menopause—testosterone.
“Having both ovaries removed results in an abrupt decrease in both estrogen and testosterone in women,” the group notes. “Therefore, one possible explanation for our results is the loss of both estrogen and testosterone.”
The team says that although their findings are important in understanding how PBO for noncancerous reasons affects the brain, larger studies are needed to determine whether it also impacts cognitive function in certain women.
Learn more in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She joined Innovate Healthcare in 2021 and has since put her unique expertise to use in her editorial role with Health Imaging.