July 27, 2022
Menopause, the time in a woman’s life when levels of the female sex hormone estrogen drop and menstrual cycles stop, may affect memory and the brain in ways that increase the risk of Alzheimer’s disease, according to several new reports. The findings add to a growing body of evidence linking menopause with Alzheimer’s, and could help explain in part why women tend to get Alzheimer’s more often than men do. Better understanding of the underlying mechanisms that cause Alzheimer’s could also lead to new, more effective treatments for the devastating brain illness that needs better treatments.
One study, in the journal Neurology, found that women who have gone through menopause tend to have more abnormal brain lesions known as white matter hyperintensities. These minute abnormalities occur in the brain’s white matter, a brain region characterized by its enrichment of brain cell connections, and can be detected on MRI brain scans. Some studies suggest they are linked to an increased risk of Alzheimer’s disease.
“White matter hyperintensities increase as the brain ages, and while having them does not mean that a person will develop dementia, larger amounts may increase a person’s risk,” said study author Dr. Monique M. B. Breteler of the German Center of Neurodegenerative Diseases in Bonn.
For the study, she and her colleagues studied 3,410 men and women whose average age was 54. They found that women who had gone through menopause had more white matter hyperintensities in their brains than men of a similar age. Menopausal women also had more of these brain lesions than women of a similar age who had not gone through menopause.
High blood pressure, a risk factor for Alzheimer’s disease, is also known to increase the likelihood of having white matter hyperintensities. In the present study, women with high blood pressure that was not being effectively treated tended to have more of these lesions.
In another study, presented at the American Heart Association conference, researchers looked at health records from more than 150,000 women who were living in Britain and were part of a large database known as the UK Biobank. They found that women who go through menopause at early ages, before age 45, are at higher risk of developing Alzheimer’s disease in later years. In the United States, most women go through menopause in their early 50s.
“Our study found that women who enter menopause very early were at greater risk of developing dementia later in life” than women who entered menopause at the average age of 50 or 51, said study author Dr. Wenting Hao of Shandong University in China. Women who went through menopause later had similar rates of dementia to women who entered menopause in their early 50s.
One reason for the increased dementia risk may be a reduction of the female sex hormone estrogen. “We know that the lack of estrogen over the long term enhances oxidative stress, which may increase brain aging and lead to cognitive impairment,” Dr. Hao said.
She said that it may be particularly important for women who go through early menopause to take steps to lower their dementia risk. Such steps include getting regular exercise, maintaining a healthy weight, not smoking, and engaging in mentally challenging activities, all of which have been shown to be associated with a lower risk of Alzheimer’s disease.
Finally, a third study looked at how symptoms of menopause may be linked to memory impairment. The study, published in the journal Menopause, looked at 404 women in northern India who ranged in age from 40 to 65. Researchers found that women who had certain symptoms of menopause, especially depression and sexual problems, were at higher risk of memory troubles. The more severe their symptoms, the greater their risk.
Many women report having “brain fog” in the years leading up to and including menopause. Declining levels of estrogen may be in part to blame. Experts note that many women who are experiencing memory troubles, such as having trouble finding the right word or losing their train of thought, may not recognize these symptoms as part of menopause. Menopause can also interfere with sleep, and poor sleep can impact both mood and memory.
The findings add to a large body of evidence linking menopause with Alzheimer’s. Other studies have shown, for example, that menopause is tied to an increase in brain levels of beta-amyloid, a toxic piece of protein that is one of the two main hallmarks of Alzheimer’s. Menopause is also tied to shrinkage of the brain, including areas affected by Alzheimer’s.
Women account for two thirds of the cases of Alzheimer’s disease in the United States. One reason is that women tend to live longer than men, and advancing age is a key risk factor for developing dementia. But as these studies suggest, the hormonal changes of menopause may also play a role, starting in middle age.
More research needs to be done to better understand how the changes of menopause impact the brain and possibly make it more susceptible to Alzheimer’s disease. If menopause is affecting your memory or otherwise interfering with day-to-day activities, you can discuss possible treatment options with your doctor.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Valerie Lohner, MSc; Gökhan Pehlivan, MD; Gerard Sanroma, PhD; et al: “The Relation Between Sex, Menopause, and White Matter Hyperintensities: The Rhineland Study.” Neurology, June 29, 2022
American Heart Association Epidemiology, Prevention, Lifestyle and Cardiometabolic Health Conference, March 1-4, 2022.
Mankamal Kaur, MSc; Maninder Kaur, PhD: “Is cognitive performance of women sensitive to the severity of menopausal symptoms?” Menopause, February 2022.