Higher Estrogen Exposure Contributes to Better Brain Health

People with higher estrogen exposure throughout their lives may be at a lower risk of developing cerebral small vessel disease.

Cerebral small vessel disease (CSVD), a form of cerebrovascular disease, affects about two million people globally each year. The condition that causes about 25% of strokes and contributes to 45% of dementia cases is more common among women than men.

Previous research has shown an increase in cerebrovascular disease rates after menopause, likely due to the absence of hormones.

The authors of a new study published in the peer-reviewed journal Neurology looked at the link between lifetime hormone exposure, which is the number of pregnancies a person had and their reproductive lifespan, and white matter hyperintensities, a common biomarker of vascular brain health that develops with age.

The study included 9,000 postmenopausal female participants, 64 years on average, living in the United Kingdom who did not have CSVD at the start of the study.

The participants were asked to provide reproductive health information, such as age at first menstruation and start of menopause, number of pregnancies, oral contraceptive use, and hormone therapy. They also underwent brain scans to look for cerebral small vessel disease by estimating white matter hyperintensities, indicating injury to the brain’s white matter.

The researchers then calculated lifetime hormone exposure by adding up the number of years participants were pregnant with the duration of their reproductive lifespan, which is the number of years from first menstruation to menopause.

The participants with higher lifetime hormone exposure had about 0.007 ml smaller volume of white matter hyperintensities than those with lower cumulative hormone exposure.

While the number of pregnancies and the reproductive lifespan affected white matter hyperintensity volumes independently, taking oral contraceptives and undergoing hormone replacement therapy did not have an impact.

Study author Kevin Whittingstall, Ph.D., of the University of Sherbrooke in Quebec, Canada, says that estrogen seems to have an important role in preserving cerebrovascular health and possibly improving response to vascular injury.

"How precisely the absence of estrogen might affect this is unclear. We hope our study highlights the importance of hormones for brain health and promotes further study in this important area of research," he told Healthnews.

The authors emphasize that the study does not prove that lower estrogen exposure causes cerebral small vessel disease; it only shows an association.

Additionally, information on reproductive factors was collected mainly based on participants’ ability to recall events, and participants may not have remembered such events correctly.

What is cerebral small vessel disease?

CSVD is an umbrella term for multiple conditions resulting from damage to small blood vessels in the brain. The disease is usually caused by the narrowing or obstruction of small blood vessels in the brain due to inflammation and/or a buildup of misfolded proteins.

It is linked to vascular dementia and may increase the risk for other types of dementia, including Alzheimer’s disease.

Because each patient has different risk factors, the most effective treatment regimen is personalized.

The most well-established approach for treating CSVD is to control vascular risk factors, notably high blood pressure.

- Whittingstall

Treatment may also include medications to reduce cholesterol and regulate glucose levels, as well as healthy lifestyle habits, including regular exercise, following a nutrient-rich diet, and quitting smoking, according to the American Brain Foundation.

The authors say that the findings emphasize the need to integrate reproductive history into managing brain health in postmenopausal women.